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Patent 2949709 Summary

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Claims and Abstract availability

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(12) Patent Application: (11) CA 2949709
(54) English Title: SWITCH VALIDATION CIRCUIT AND METHOD
(54) French Title: CIRCUIT ET PROCEDE DE VALIDATION PAR COMMUTATION
Status: Dead
Bibliographic Data
(51) International Patent Classification (IPC):
  • A61M 37/00 (2006.01)
  • G16H 20/17 (2018.01)
  • A61M 5/142 (2006.01)
  • A61M 5/168 (2006.01)
  • G06F 19/00 (2011.01)
(72) Inventors :
  • LEMKE, JOHN (United States of America)
  • SATRE, SCOT (United States of America)
  • CHEN, CORINNA X. (United States of America)
  • READ, BRIAN W. (United States of America)
  • DOUGHERTY, JASON E. (United States of America)
  • JOSHI, NITIN B. (United States of America)
(73) Owners :
  • INCLINE THERAPEUTICS, INC. (United States of America)
(71) Applicants :
  • INCLINE THERAPEUTICS, INC. (United States of America)
(74) Agent: SMART & BIGGAR IP AGENCY CO.
(74) Associate agent:
(45) Issued:
(86) PCT Filing Date: 2015-06-03
(87) Open to Public Inspection: 2015-12-10
Availability of licence: N/A
(25) Language of filing: English

Patent Cooperation Treaty (PCT): Yes
(86) PCT Filing Number: PCT/US2015/033990
(87) International Publication Number: WO2015/187834
(85) National Entry: 2016-11-18

(30) Application Priority Data:
Application No. Country/Territory Date
14/296,085 United States of America 2014-06-04

Abstracts

English Abstract

A switch-operated therapeutic agent delivery device is described. Embodiments of the operated therapeutic agent delivery device include a switch that can be operated by a user, a device controller connected to the switch through a switch input where the device can actuate the device when certain predetermined conditions are met, following performance of both a digital switch validation test and an analog switch validation test.


French Abstract

Cette invention concerne un dispositif de transport d'agent thérapeutique actionné par commutateur. Des modes de réalisation du dispositif de transport d'agent thérapeutique mis en oeuvre comprennent un commutateur qui peut être actionné par un utilisateur, un système de commande du dispositif connecté au commutateur par une entrée de commutateur, le dispositif pouvant actionner le dispositif lorsque certaines conditions prédéterminées sont remplies, à la suite de l'accomplissement d'un test de validation de commutateur numérique et d'un test de validation de commutateur analogique.

Claims

Note: Claims are shown in the official language in which they were submitted.



CLAIMS

WHAT IS CLAIMED IS:

1. An iontophoretic drug delivery device adapted to validate the operation
of a user-selectable activation
switch to deliver a dose of drug using both digital and analog validation, the
device comprising:
a battery having a battery voltage;
a switch configured to be activated by a user to deliver a dose of drug, the
switch having a low voltage
side and a high voltage side;
a first input line on the high side and a second input line on the low side,
wherein the first and second
input lines are connected to the battery;
a first analog test input line on the high side and a second analog test input
line on the low side;
a first digital test input line on the high side and a second digital test
input line on the low side;
a controller configured to perform both a digital validation of the switch
following a release event of
the switch and to perform an analog validation of the switch following the
release event, wherein
the controller is further configured to initiate a failure mode for the drug
delivery device if the
analog validation of the switch fails.
2. The device of claim 1, further comprising a circular buffer configured
to store a plurality of sequential
samples from an input line on the high voltage side of the switch, wherein the
newest sample replaces the
oldest sample.
3. The device of claim 1, wherein the controller is configured to
sequentially sample an input line on the high
voltage side of the switch, store a window of sequential samples, and compare
a plurality of more recent
sequential samples to a plurality of older sequential samples within the
stored window of samples to detect
the release event.
4. The device of claim 1, wherein the first and second analog test input
lines are connected to the controller,
and further wherein the controller configured to fail the analog validation if
a voltage on the first analog
test line is below a first predetermined fraction of the battery voltage or if
a voltage on the second analog
test line is greater than a second predetermined fraction of the battery
voltage.
5. The device of claim 1, wherein the first and second analog test input
lines are connected to the controller,
and further wherein the controller configured to fail the analog validation if
a voltage on the first analog
test line is less about 0.8 times the battery voltage or if a voltage on the
second analog test line is greater
than about 0.2 time the battery voltage.
6. The device of claim 1, wherein the first and second digital test input
lines are connected to the controller,
and further wherein the controller is configured to fail the digital
validation if a value of the first digital test
input line does not match a value of the first input line or if a value of the
second digital test input line does
not match a value of the second input line.

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7. The device of claim 1, wherein the first and second digital test input
lines are connected to the controller,
and further wherein the controller is configured to fail the digital
validation if the first digital input line is
low or if the second digital input line is high.
8. The device of claim 1, wherein the controller is further configured to
perform the analog validation of the
switch and the digital validation of the switch following a second release of
the switch within less than
about 100 msec.
9. An iontophoretic drug delivery device adapted to validate the operation
of a user-selectable activation
switch to deliver a dose of drug using both digital and analog validation, the
device comprising:
a battery having a battery voltage;
a switch configured to be activated by a user to deliver a dose of drug, the
switch having a low voltage
side and a high voltage side;
a first input line on the high side and a second input line on the low side,
wherein the first and second
input lines are connected to the battery;
a first analog test input line on the high side and a second analog test input
line on the low side,
wherein the first and second analog test inputs lines are connected to a
controller; and
a first digital test input line on the high side and a second digital test
input line on the low side, wherein
the first and second digital test input lines are connected to the controller;
wherein the controller is configured to perform a digital validation of the
switch, following a second
release of the switch within a predetermined time period, and to perform an
analog validation of
the switch following the second release of the switch within the predetermined
time period, further
wherein the controller is configured to fail the analog validation if a
voltage on the first analog test
line is below a first predetermined fraction of the battery voltage or if a
voltage on the second
analog test line is greater than a second predetermined fraction of the
battery voltage, and to fail
the digital validation if the first digital input line is low or if the second
digital input line is high;
and wherein the controller initiates a failure mode for the drug delivery
device if the analog validation
of the switch fails.
10. A method of validating operation of a switch of an iontophoretic device
using both digital and analog
validation, wherein the switch is user-activated to deliver a dose of a drug
from a drug delivery device, the
method comprising:
monitoring the switch to determine a release event;
performing a digital validation of the switch following the release event
using a dose switch circuit and
failing the digital validation if a secondary digital input on a high side of
the switch is low or if a
secondary digital input on a low side of the switch is high;
performing an analog validation of the switch if the digital validation passes
and failing the analog
validation if a measurement of a high side voltage is less than a first
predetermined fraction of a
battery voltage for the drug delivery device or if a measurement of a low side
voltage is greater
than a second predetermined fraction of the battery voltage; and
initiating a failure mode for the drug delivery device if the analog
validation of the switch fails.

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11. The method of claim 10, wherein monitoring the switch comprises
sequentially sampling a switch input,
storing a window of sequential samples, and comparing a plurality of more
recent sequential samples to a
plurality of older sequential samples within the stored window of samples to
detect the release event.
12. The method of claim 10, wherein monitoring the switch comprises
sequentially sampling a switch input,
storing a window of sequential samples, and comparing three or more recent
sequential samples to three or
more older sequential samples within the stored window of samples to detect
the release event.
13. The method of claim 10, wherein initiating the failure mode comprises
turning off the delivery device.
14. The method of claim 10, wherein initiating the failure mode comprises
inactivating the delivery device.
15. The method of claim 10, further comprising re-starting a button sampling
process of the drug delivery
device if the digital validation of the switch fails.
16. The method of claim 10, wherein performing the digital validation
comprises failing the digital validation if
a secondary digital input on a first side of the switch does not match a
primary digital input on the first side
of the switch, or a secondary digital input on a second side of the switch
does not match a primary digital
input on the second side of the switch.
17. The method of claim 10, wherein performing the analog validation comprises
failing the analog validation
if a measurement of a high side voltage is less about 0.8 times a battery
voltage for the drug delivery
device, or a measurement of a low side voltage is greater than about 0.2 time
the battery voltage.
18. The method of claim 10, wherein performing the analog validation comprises
sequentially measuring a
high side voltage and a low side voltage using an analog to digital converter
(ADC) and failing the analog
validation if the high side voltage is below a first predetermined threshold
or the low side voltage is above a
second predetermined threshold.
19. The method of claim 10, wherein the release event comprises a second
release of the switch within a
predetermined time period.
20. The method of claim 10, wherein the release event comprises a second
release of the switch within less
than about 100 msec.

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Description

Note: Descriptions are shown in the official language in which they were submitted.


CA 02949709 2016-11-18
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SWITCH VALIDATION CIRCUIT AND METHOD
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit to U.S. pat;,nt application no.
14/296,085, filed on 6/4/2014
(published as US-2014-0288526-A1) and tilted "SWITCH VALIDATION CIRCUIT AND
METHOD," herein
incorporated by reference in their entirety.
BACKGROUND
[0002] A switch-operated therapeutic agent delivery device can provide
single or multiple doses of a
therapeutic agent to a patient by activating a switch. Upon activation, such a
device delivers a therapeutic agent to a
patient. A patient-controlled device offers the patient the ability to self-
administer a therapeutic agent as the need
arises. For example, the therapeutic agent can be an analgesic agent that a
patient can administer whenever sufficient
pain is felt.
[0003] One means of patient controlled analgesia is patient controlled
intravenous infusion, which is carried
out by an infusion pump, which is pre-programmed to respond to the
instructions of a patient within certain pre-
determined dosing parameters. Such intravenous infusion pumps are commonly
used for control of postoperative
pain. The patient initiates infusion of a dose of analgesic, which is
typically a narcotic, by signaling a control unit.
The unit receives the signal and, if certain conditions are met, begins
infusion of the drug through a needle that has
been inserted into one of the patient's veins.
[0004] Another form of patient controlled analgesia is electrotransport
(e.g., iontophoresis, also referred to as
iontophoretic drug delivery). In electrotransport drug delhe.y, a therapeutic
agent is actively transported into the
body by electric current. Examples of electrotransport include iontophoresis,
electroosmosis and electroporation.
Iontophoresis delivery devices typically comprise at least two electrodes
connected to reservoirs, a voltage source,
and a controller that controls delivery of the therapeutic agent by applying
the voltage across the pair of electrodes.
Usually at least one of the reservoirs contains a charged therapeutic agent
(drug), while at least one reservoir
contains a counter-ion and no therapeutic agent. The therapeutic agent, which
is a charged species, is driven from
the reservoir containing the therapeutic agent and into and across the skin
into the patient to whom the reservoirs are
attached.
[0005] In addition to therapeutic agent, the reservoirs may contain
other charged and uncharged species. For
example, the reservoirs are often hydrogels, which contain water as a
necessary constituent. The reservoirs may also
contain electrolytes, preservatives, antibacterial agents, and other charged
and uncharged species.
[0006] For safety reasons, it is essential that any patient-controlled
drug delivery device, and particularly an
electrotransport device delivering a therapeutic agent (e.g., an opoid
analgesic such as fentanyl) be tightly regulated
to prevent the inadvertent delivery of agent to a patient. For example, short
circuits in the device may result in
erroneous, additional delivery of drug. Since patient-activated dosing systems
must include a dose switch that is
selected, e.g., pushed, by a patient to deliver a dose, one particularly
vulnerable aspect is this switch. A short circuit
in the dose switch circuit could be interpreted by control logic (e.g.,
processor) of the device as valid dose switch
presses, and potentially cause the system to deliver a dose even without a
valid patient request. Such short circuits
could be caused by contamination or corrosion.
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[0007] Described herein are methods and apparatuses (e.g., system and
devices) that validate the integrity of a
dose switch circuit and signal characteristics prior to initiating a dose. In
particular, the apparatuses and methods
described herein perform validation before each dose initiation, and the
validation process (e.g., measurements used
to determine if the switch is properly functioning) do not interfere with
normal operation, including in particular
actual presses of the dose switch. Finally, the apparatus and methods
described herein are demonstrably reliable to a
high degree of certainty. These apparatus and methods may therefore address
the issues raised above.
SUMMARY OF THE DISCLOSURE
[0008] The present invention addresses a need in the art of patient-
controlled drug administration devices,
especially those devices that are subject to humidity and other contaminants
during storage and use, such as
iontophoresis devices. The inventors have identified contaminants present in
storage and use of iontophoresis
devices, as being particularly problematic, as they can cause the device to
malfunction. For example, in
electrotransport, such as iontophoresis ¨ and on-demand drug delivery in
general ¨ faulty circuitry can be especially
problematic, as it can, in some instances, cause the device to fail to deliver
a full dose, to deliver more than the
desired dose, to deliver one or more doses during storage, to deliver one or
more doses in the absence of a patient
instruction, etc. The potential for contamination of electronic circuitry is
especially present in iontophoretic drug
delivery systems, as the reservoirs employed contain water as well as other
charged and uncharged species ¨ such as
charged therapeutic agent, electrolytes, preservatives and antibacterial
agents ¨ which can contaminate circuitry,
such as activation switches, circuit leads, circuit traces, etc. (Other drug
delivery methods, such as patient-activated
pumps, can present similar potential for contamination, especially with
environmental humidity and airborne
contaminants.) In combination with voltages and currents applied to the
circuitry during drug delivery (and in some
cases storage), contaminants can cause current leaks, short circuits
("shorts", including intermittent shorts) and other
spurious signals that can interfere with the proper operation of the device.
Other causes of circuit malfunction can
also be introduced during manufacturing or in the use environment. The
inventors have identified a particular part of
the circuitry¨the activation switch, as a point that is in some cases
especially vulnerable to contamination and
malfunction. The inventors have further identified the activation switch as a
part of the circuitry that is a focal point
for detecting and averting potential and actual circuit faults before they
negatively impact device performance, and
ultimately, patient health.
[0009] Embodiments of the device and methods described herein address
the issues raised above by providing
means to actively seek out and detect circuit faults and precursors to faults.
The means employed involve
performing active checks of the device circuitry while the device is powered
on, e.g. before, during or after drug
delivery. Some embodiments of the device and methods described herein provide
for active detection of circuit
faults and/or precursors to faults after any button push or after any event
that mimics a button push, such as a
spurious voltage. Some embodiments provide for active detection of circuit
faults or precursors to faults, for
instance, between button pushes in an activation sequence, during drug
delivery, and between drug delivery
sequences (i.e. after one dose has been delivered and before commencement of
delivery of another dose).
[00010] In some embodiments, the active testing during use of the device
is in addition to testing during or
following device manufacturing.
[00011] Thus there is described herein are therapeutic agent delivery
devices, such as electrotransport device
(e.g. an iontophoresis device), which may include a housing and components
adapted for containing and delivering
the therapeutic agent to a patient, a processor for controlling delivery of
the therapeutic agent to the patient, and
circuitry and/or control logic for detecting one or more faults and/or
precursors to faults during device operation,
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and for disabling the device upon detection of a fault or a precursor to a
fault. In some embodiments, the device is
an iontophoresis device or other electrotransport device. In some embodiments,
the device further comprises an
alarm for alerting a patient and/or caregiver that the device has detected a
fault and/or precursor to a fault. In some
embodiments, the device further comprises an alarm for alerting a patient
and/or caregiver that the device is being
disabled. In some embodiments, the either or both alarms are at least one of:
an audible tone (or tones), at least one
visual indicator, or a combination of two or more thereof. In some
embodiments, the means for containing and
delivering therapeutic agent to the patient includes one or more therapeutic
agent reservoirs connected to one or
more electrodes for applying a current to the reservoirs and actively
transporting therapeutic agent across an outer
surface of a patient, such as the skin. In some embodiments, the means for
detecting a fault or a precursor to a fault
is configured to detect a fault in a switch, such as an activation switch, or
other circuit component, such as a trace, a
connector, a power supply, an integrated circuit, a lead, a chip, a resistor,
a capacitor, an inductor or other circuit
component. In some embodiments the means for controlling delivery of the
therapeutic agent comprises a pre-
programmed or programmable integrated circuit controller, such as an ASIC.
[00012] In some embodiments, the circuitry described herein is
incorporated into a device for delivery of a
therapeutic agent (drug) to a patient. In some embodiments, the device is a
patient-activated drug delivery device. In
some embodiments, the device is an electrotransport drug delivery device. In
some embodiments, the drug delivery
device is an iontophoretic drug delivery device. In some embodiments, the drug
to be delivered is an opioid
analgesic. In some embodiments, the opioid analgesic is a pharmaceutically
acceptable salt of fentanyl or sufentanil,
such as fentanyl hydrochloride.
[00013] In some embodiments, the methods described herein are executed by a
device processor, which may
include or be referred to as a controller, especially a controller of a device
for delivery of a therapeutic agent (drug)
to a patient. In some embodiments, the methods are carried out by the
controller during one or more stages of drug
delivery ¨ e.g., during the period of time between pushes of an activation
button, during delivery of the drug,
between delivery sequences, etc. In some preferred embodiments, the testing is
carried out after any button push or
anything that appears to be a button push. In particularly preferred
embodiments, the methods are under active
control of the controller, meaning that the controller initiates detection of
faults and precursors to faults in the
circuitry, e.g. after a button push or anything that appears to be a button
push. In some embodiments, upon detection
of a fault or precursor to a fault, the controller takes appropriate action,
such as setting a fault detection flag, logging
the fault in memory for retrieval at a later time, setting a user warning
(such as an indicator light and/or audible
tone), and/or disabling the device. In this regard, methods for disabling a
device upon detection of a fault are
described in United States Patent No. 7,027,859 to McNichols et al., which is
incorporated herein in its entirety; in
particular column 6, line 65 through column 11, line 35 are specifically
incorporated by reference as teaching
various ways to disable a circuit.
[00014] Described herein are switch operated devices, such as a drug
delivery device (e.g., a drug delivery
pump or iontophoresis device) comprising: (a) a device switch configured to be
operated by a user, which provides
a switch signal to a switch input of a device controller when operated by a
user; (b) the device controller, having
said switch input operatively connected to the switch, and configured to
receive the switch signal from the switch,
the device controller being configured to actuate the device when the switch
signal meets certain predetermined
conditions and to control and receive signals from a switch integrity test
subcircuit; and (c) the switch integrity test
subcircuit, which is configured to detect a fault or a precursor to a fault in
the switch and provide a fault signal to the
controller. When the controller receives a fault signal from the switch
integrity test subcircuit, it executes a switch
fault subroutine when a fault or a precursor to a fault is detected. In some
embodiments, the switch integrity test
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subcircuit is configured to check for and detect a fault or a precursor to a
fault in the switch. In some embodiments,
the switch integrity test subcircuit is configured to test for and detect at
least one fault or precursor to a fault such as
contamination, short circuits, (including intermittent short circuits),
compromised circuit components (including
malfunctioning resistors, integrated circuit pins, and/or capacitors), etc.
[00015] In some embodiments, the switch integrity test subcircuit is
configured to test for and detect a voltage
(or change in voltage) between the switch input and ground or some
intermediate voltage above ground, a short
between the switch input and a voltage pull up or some intermediate voltage
below the pull up voltage. In some
preferred embodiments the switch integrity test subcircuit is configured to
test for and detect a voltage (or change in
voltage) between the switch input and some intermediate voltage above ground
(a low voltage, VI) and/or a short
between the switch input and a some intermediate voltage below the pull up
voltage (high voltage VH). Thus, the
switch integrity test subcircuit is able to detect a non-determinant signal
that indicates contamination (e.g. moisture
and/or particulates), corrosion, a damaged circuit resistor, a damaged
integrated circuit pin, etc. In some
embodiments, the switch fault subroutine includes at least one of: activating
a user alert feature, logging detection of
faults or precursors to faults, deactivating the device, or one or more
combinations thereof. In some embodiments,
the controller is configured to measure a voltage or a rate of change of
voltage at the switch input and execute the
switch fault subroutine when the voltage or rate of change of voltage at the
switch input fails to meet one or more
predetermined parameters. In some embodiments, the device is an iontophoresis
delivery device comprising first and
second electrodes and reservoirs, at least one of the reservoirs containing
therapeutic agent to be delivered by
iontophoresis. In some embodiments, the predetermined conditions for actuating
the device include the user
activating the switch at least two times within a predetermined period of
time. In some embodiments, the switch
input is pulled up to a high voltage when the switch is open and the switch
input is a low voltage when the switch is
closed.
[00016]
Some embodiments described herein provide a method of switch fault detection
in a switch operated
device, said device comprising: (a) a device switch connected to a switch
input of a device controller; (b) the device
controller comprising said switch input; and (c) a switch integrity test
subcircuit, said method comprising said
controller: (i) activating the switch integrity test subcircuit; (ii)
detecting a voltage condition at the switch input; and
(iii) activating a switch fault subroutine if the voltage condition at the
switch input fails to meet one or more
predetermined conditions. In some embodiments, the steps of activating the
switch integrity test subcircuit and
detecting a voltage condition at the switch input are executed continuously or
periodically throughout use of the
device. In some embodiments, the switch fault subroutine includes, for
example, activating a user alert feature,
logging detection of faults or precursors to faults, deactivating the device,
or one or more combinations thereof. In
some embodiments, the voltage condition is a voltage, a change in voltage or
both. In some embodiments, the
controller detects the voltage at the switch input under conditions in which
the voltage should be zero or nearly zero
if the switch integrity is within operating norms, and activates the switch
fault subroutine if the voltage is
significantly higher than zero. In some embodiments, the controller detects
the voltage at the switch input under
conditions in which the voltage should be equal to a pull up voltage or nearly
equal to the pull up voltage if the
switch integrity is within operating norms, and activates the switch fault
subroutine if the voltage is significantly
lower than the pull up voltage. In some embodiments, the controller detects a
change in voltage at the switch input
under conditions in which the voltage is expected to fall to zero or nearly to
zero after within a predetermined period
if the switch integrity is within operating norms, and activates the switch
fault subroutine if the voltage fails to fall
to zero or nearly to zero within the predetermined period. In some
embodiments, the controller detects a change in
voltage at the switch input under conditions where, the voltage should rise to
a pull up voltage or nearly to the pull
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up voltage within a predetermined period if the switch integrity is within
operating norms, and activates the switch
fault subroutine if the voltage fails to rise to the pull up voltage or nearly
to the pull up voltage within the
predetermined period.
[00017] Some embodiments described herein provide a switch operated
iontophoresis therapeutic agent
delivery device, comprising: (a) a power source; (b) first and second
electrodes and reservoirs, at least one of the
reservoirs containing the therapeutic agent; (c) a device switch, which
provides a switch signal to a switch input of a
device controller when operated by a user, the device controller, having said
switch input operatively connected to
the switch, whereby the controller receives the switch signal from the switch,
the device controller being
operatively connected to a power source that provides power to the first and
second electrodes for delivering
therapeutic agent to a patient; and (d) a switch integrity test subcircuit,
which is configured to detect a fault in the
switch and cause the controller to execute a switch fault subroutine when a
fault is detected. In some embodiments,
the therapeutic agent is an opioid analgesic as described herein, such as
fentanyl or sufentanil or a pharmaceutically
acceptable salt, analog or derivative thereof.
[00018] A method of switch fault detection in a user operated
iontophoresis therapeutic agent delivery device,
said device comprising: (a) a power source; (b) first and second electrodes
and reservoirs, at least one of the
reservoirs containing the therapeutic agent; (c) a device switch connected to
a switch input of a device controller; (d)
the device controller comprising said switch input and configured to control
power to the first and second electrodes,
thereby controlling delivery of the therapeutic agent; and (e) a switch
integrity test subcircuit, said method
comprising said controller: (i) activating the switch integrity test
subcircuit; detecting a voltage condition at the
switch input; and (ii) activating a switch fault subroutine if the voltage
condition at the switch input fails to meet
one or more predetermined conditions. In some embodiments, the switch fault
subroutine includes, for example,
activating a user alert, deactivating the device, or both.
[00019] Also described herein are methods of validating the operation of
a switch including a user-activated to
deliver a dose of a drug from a drug delivery device. Any of the drug delivery
devices described herein may be
transdermal drug delivery devices. A method of validating the operation of a
switch (e.g., a user-activated switch)
to deliver a dose of drug from a (e.g., transdermal) drug delivery device may
include: monitoring the switch to
determine a release event; performing a digital validation of the switch
following the release event; performing an
analog validation of the switch following the release event; and initiating a
failure mode for the drug delivery device
if the analog validation of the switch fails.
[00020] In general, the methods of validating the operation of a switch and
apparatus configured to validate the
operation of a switch may include button sampling when monitoring the switch.
For example, monitoring the
switch may generally include sequentially sampling a switch input, storing a
window of sequential samples, and
comparing a plurality of more recent sequential samples to a plurality of
older sequential samples within the stored
window of samples to detect the release event. Sequential sampling may refer
to periodically sampling an input to
the switch (e.g., the low or high side of the switch) at regular intervals,
e.g., every 1 ms, 2 ms, 3 ms, 4 ms, 5 ms, 6
ms, 7 ms, 8 ms, 9 ms, 10 ms, etc. The plurality of more recent sequential
samples may refer to 2 or more, 3 or
more, 4 or more, 5 or more, etc., samples taken sequentially in time. The
window of stored sequential samples may
be a circular buffer, storing a rolling window of samples (e.g., any
appropriate number of samples may be stored,
with the most recent sample replacing the oldest sample in a continuous
manner). Thus, in general, a group of
newer sequential samples may be compared to a group of older sequential
samples and if the state change is made
(e.g., when the older samples all indicate the switch is closed, and the newer
samples all indicate the switch is open,
a release event may be confirmed. For example, monitoring the switch to
determine a release event may include
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sequentially sampling a switch input, storing a window of sequential samples,
and comparing three or more recent
sequential samples to three or more older sequential samples within the stored
window of samples to detect the
release event, e.g., when the three or more recent samples indicate an open
switch and the three or more older
samples indicate a closed switch. The older samples and the more recent
samples are generally non-overlapping.
[00021] In general, the failure mode, as discussed above, may include
suspending operation of the device,
shutting the device off, or restarting the device. For example, the failure
mode may include preventing delivery of
drug by the device, including (but not limited to) turning off the drug
delivery device, and/or locking (e.g.,
inactivating) the drug delivery device.
[00022] In general, both digital and analog validation tests may be
performed on the switch, typically during a
period when the switch is reliable predicted to be in the "open" (inactivated)
state. The inactivated state is known
most reliably immediately or shortly (e.g. within micro- to mill- seconds)
following user activation, as it may be
impossible for a user to more quickly activate the switch immediately after
one (or better yet, a series) of "pushes"
or other activating input. Thus, in variations in which the user pushes a
button (activates the switch) multiple times,
e.g., twice, within a predetermined activation period (e.g., two quick
'clicks' in succession), during the period (e.g.,
between about 8 sec and 500 msec, between about 8 sec and 400 msec, between
about 8 sec and 300 msec,
between about 8 sec and 200 msec; less than about 500 msec, less than about
400 msec, less than about 300 msec,
less than about 200 msec, less than about 150 msec, less than about 100 msec,
etc.) it is unlikely that the user would
validly activate the switch, and therefore the state of the switch should be
in the open state. Thus, both the analog
and digital validation may be performed within this period, which may be
referred to as a test period or test window.
[00023] Analog validation of the switch typically means determining the
actual voltage value of one or both
sides of the switch and comparing them to one or more thresholds to confirm
that they are within acceptable
parameters. For example, performing the analog validation of the switch may
comprise performing an analog
validation of the switch if the digital validation passes. Either or both
digital and analog validation may include
performing the analog validation using a dose switch circuit. The dosing
switch circuit may be part of the
processor/controller.
[00024] In general, method or apparatus may perform the digital validation
and analog validation sequentially
or in parallel. For example, the digital validation step may be performed
before the analog validation step; the
analog validation step may be performed only if the digital validation passes
(e.g., does not fail digital validation);
the drug delivery apparatus may be re-started (e.g., the button sampling
process may be re-started) if the digital
validation of the switch fails.
[00025] The digital validation generally includes a comparison of the
logical values of digital validation lines
from one or both sides of the switch to expected values based on the inputs
from the power source (e.g., battery) to
the switch. For example, digital validation may "fail" (e.g., failing the
digital validation) if a secondary digital input
on a first side of the switch does not match a primary digital input on the
first side of the switch, or a secondary
digital input on a second side of the switch does not match a primary digital
input on the second side of the switch.
The primary digital input may be a first input line connected to the battery
and the high side of the switch and the
secondary digital input may be a second input line connected to the battery
(e.g., a negative terminal of the battery)
and the low side of the switch. The secondary digital input line may be a
first digital test input line also connected
on the high side of the switch. Similarly, the analog validation may be
performed using a first and second analog
input line; the first analog test input line may be on the high side of the
switch and the second analog test input line
may be on the low side of the switch.
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[00026] Performing the digital validation may include failing the digital
validation if a secondary digital input
on a high side of the switch is low or if a secondary digital input on a low
side of the switch is high.
[00027] Performing the analog validation may include failing the analog
validation if a measurement of a high
side voltage is less than a first predetermined fraction (e.g., 90%, 85%, 80%,
75%, 70%, 65%, etc.) of a battery
voltage for the drug delivery device, or a measurement of a low side voltage
is greater than a second predetermined
fraction (e.g., 90%, 85%, 80%, 75%, 70%, 65%, etc.) of the battery voltage.
For example, performing the analog
validation may include failing the analog validation if a measurement of a
high side voltage is less about 0.8 times a
battery voltage for the drug delivery device, or a measurement of a low side
voltage is greater than about 0.2 times
the battery voltage. Performing the analog validation may include sequentially
measuring a high side voltage and a
low side voltage using an analog to digital converter (ADC) and failing the
analog validation if the high side voltage
is below a first predetermined threshold or the low side voltage is above a
second predetermined threshold.
[00028] As mentioned, digital validation of the switch may be performed
before the analog validation of the
switch. Alternatively, analog validation of the switch may be performed before
the digital validation of the switch.
[00029] In general, a release event may include a second release of the
switch within a predetermined time
period. For example, a release event may comprise a second release of the
switch within less than about 400 msec,
300 msec, 200 msec, 100 msec, etc.
[00030] For example, a method of validating operation of a switch, wherein
the switch is user-activated to
deliver a dose of a drug from a drug delivery device, may include: monitoring
the switch to determine a release
event; performing a digital validation of the switch following the release
event using a dose switch circuit and
failing the digital validation if a secondary digital input on a high side of
the switch is low or if a secondary digital
input on a low side of the switch is high; performing an analog validation of
the switch if the digital validation
passes and failing the analog validation if a measurement of a high side
voltage is less than a first predetermined
fraction of a battery voltage for the drug delivery device or if a measurement
of a low side voltage is greater than a
second predetermined fraction of the battery voltage; and initiating a failure
mode for the drug delivery device if the
analog validation of the switch fails.
[00031] Any of the drug delivery devices described herein may be adapted
to validate the operation of a user-
selectable activation switch to deliver a dose of drug. For example a drug
delivery device may include: a battery
having a battery voltage; a switch configured to be activated by a user to
deliver a dose of drug, the switch having a
low voltage side and a high voltage side; a first input line on the high side
and a second input line on the low side,
wherein the first and second input lines are connected to the battery; a first
analog test input line on the high side and
a second analog test input line on the low side; a first digital test input
line on the high side and a second digital test
input line on the low side; and a controller configured to pe-form a digital
validation of the switch following a
release event of the switch and to perform an analog validation of the switch
following the release event, wherein
the controller is further configured to initiate a failure mode for the drug
delivery device if the analog validation of
the switch fails.
[00032] In general, any of these devices may include a circular buffer
configured to store a plurality of
sequential samples from an input line on the high voltage side of the switch,
wherein the newest sample replaces the
oldest sample.
[00033] Further, the controller may be configured determine a release
event on the switch by being configured
to sequentially sample an input line on the high voltage side of the switch,
store a window of sequential samples,
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and compare a plurality of more recent sequential samples to a plurality of
older sequential samples within the
stored window of samples to detect the release event.
[00034] The first and second analog test input lines may be connected to
the controller, and further wherein the
controller configured to fail the analog validation if a voltage on the first
analog test line is below a first
predetermined fraction of the battery voltage or if a voltage on the second
analog test line is greater than a second
predetermined fraction of the battery voltage. For example, the first and
second analog test input lines may be
connected to the controller, and further wherein the controller configured to
fail the analog validation if a voltage on
the first analog test line is less about 0.8 times the battery voltage or if a
voltage on the second analog test line is
greater than about 0.2 time the battery voltage.
[00035] The first and second digital test input lines may be connected to
the controller, wherein the controller is
configured to fail the digital validation if a value of the first digital test
input line does not match a value of the first
input line or if a value of the second digital test input line does not match
a value of the second input line. For
example, the first and second digital test input lines may be connected to the
controller, wherein the controller is
configured to fail the digital validation if the first digital input line is
low or if the second digital input line is high.
[00036] The controller may be configured to perform the analog validation
of the switch and the digital
validation of the switch following a second release of the switch within less
than about 500 msec (e.g., less than
about 400 msec, less than about 300 msec, less than about 200 msec, less than
about 100 msec, etc.).
[00037] For example, a drug delivery device adapted to validate the
operation of a user-selectable activation
switch to deliver a dose of drug may include: a battery having a battery
voltage; a switch configured to be activated
by a user to deliver a dose of drug, the switch having a low voltage side and
a high voltage side; a first input line on
the high side and a second input line on the low side, wherein the first and
second input lines are connected to the
battery; a first analog test input line on the high side and a second analog
test input line on the low side, wherein the
first and second analog test inputs lines are connected to a controller; and a
first digital test input line on the high
side and a second digital test input line on the low side, wherein the first
and second digital test input lines are
connected to the controller; wherein the controller is configured to perform a
digital validation of the switch,
following a second release of the switch within a predetermined time period,
and to perform an analog validation of
the switch following the second release of the switch within the predetermined
time period, further wherein the
controller is configured to fail the analog validation if a voltage on the
first analog test line is below a first
predetermined fraction of the battery voltage or if a voltage on the second
analog test line is greater than a second
predetermined fraction of the battery voltage, and to fail the digital
validation if the first digital input line is low or if
the second digital input line is high; and wherein the controller initiates a
failure mode for the drug delivery device if
the analog validation of the switch fails.
[00038] For example any of the apparatuses described herein may be
configured as are iontophoretic drug
delivery devices adapted to validate the operation of a user-selectable
activation switch to deliver a dose of drug
using both digital and analog validation. These iontophoretic drug delivery
devices may be configured (and
particularly useful) for delivery of fentanyl or sufentanil. An iontophoretic
drug delivery device may include: a
battery having a battery voltage; a switch configured to be activated by a
user to deliver a dose of drug, the switch
having a low voltage side and a high voltage side; a first input line on the
high side and a second input line on the
low side, wherein the first and second input lines are connected to the
battery; a first analog test input line on the
high side and a second analog test input line on the low side; a first digital
test input line on the high side and a
second digital test input line on the low side; a controller configured to
perform both a digital validation of the
switch following a release event of the switch and to perform an analog
validation of the switch following the
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release event, wherein the controller is further configured to initiate a
failure mode for the drug delivery device if the
analog validation of the switch fails.
[00039] Any of the apparatuses (e.g., iontophoretic devices) described
herein may include a circular buffer
configured to store a plurality of sequential samples from an input line on
the high voltage side of the switch,
wherein the newest sample replaces the oldest sample. That is, the controller
may sample and analyze the high side
of the switch and start validation when the high side goes low (indicating a
press event) and then return to high
(indicating a release event).
[00040] Any of the controllers described herein may be configured to
sequentially sample an input line on the
high voltage side of the switch, store a window of sequential samples, and
compare a plurality of more recent
sequential samples to a plurality of older sequential samples within the
stored window of samples to detect the
release event. Detecting a 'release event' may including detecting a preceding
'press event'.
[00041] In any of the apparatuses described herein, the first and second
analog test input lines may be
connected to the controller, and the controller may be configured to fail the
analog validation if a voltage on the first
analog test line is below a first predetermined fraction of the battery
voltage or if a voltage on the second analog test
line is greater than a second predetermined fraction of the battery voltage.
The device of claim 1, wherein the first
and second analog test input lines are connected to the controller, and
further wherein the controller configured to
fail the analog validation if a voltage on the first analog test line is less
about 0.8 times the battery voltage or if a
voltage on the second analog test line is greater than about 0.2 time the
battery voltage. For example, the first and
second digital test input lines may be connected to the controller, and the
controller may be configured to fail the
digital validation if a value of the first digital test input line does not
match a value of the first input line or if a value
of the second digital test input line does not match a value of the second
input line. The first and second digital test
input lines may be connected to the controller, and the controller may be
configured to fail the digital validation if
the first digital input line is low or if the second digital input line is
high.
[00042] The controller may be further configured to perform the analog
validation of the switch and the digital
validation of the switch following a second release of the switch within less
than about 100 msec.
[00043] An iontophoretic drug delivery device adapted to validate the
operation of a user-selectable activation
switch to deliver a dose of drug using both digital and analog validation may
include: a battery having a battery
voltage; a switch configured to be activated by a user to deliver a dose of
drug, the switch having a low voltage side
and a high voltage side; a first input line on the high side and a second
input line on the low side, wherein the first
and second input lines are connected to the battery; a first analog test input
line on the high side and a second analog
test input line on the low side, wherein the first and second analog test
inputs lines are connected to a controller; and
a first digital test input line on the high side and a second digital test
input line on the low side, wherein the first and
second digital test input lines are connected to the controller; wherein the
controller is configured to perform a
digital validation of the switch, following a second release of the switch
within a predetermined time period, and to
perform an analog validation of the switch following the second release of the
switch within the predetermined time
period, further wherein the controller is configured to fail the analog
validation if a voltage on the first analog test
line is below a first predetermined fraction of the battery voltage or if a
voltage on the second analog test line is
greater than a second predetermined fraction of the battery voltage, and to
fail the digital validation if the first digital
input line is low or if the second digital input line is high; and wherein the
controller initiates a failure mode for the
drug delivery device if the analog validation of the switch fails.
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[00044] Any of the methods described herein may be methods of validating
operation of a switch of an
iontophoretic device using both digital and analog validation, wherein the
switch is user-activated to deliver a dose
of a drug (e.g., fentanyl or sufentanil) from a drug delivery device. For
example, any of these methods may be
methods of validating operation of a switch of an iontophoretic device using
both digital and analog validation for
iontophoretic delivery of fentanyl or sufentanil. Such methods may include:
monitoring the switch to determine a
release event; performing a digital validation of the switch following the
release event using a dose switch circuit
and failing the digital validation if a secondary digital input on a high side
of the switch is low or if a secondary
digital input on a low side of the switch is high; performing an analog
validation of the switch if the digital
validation passes and failing the analog validation if a measurement of a high
side voltage is less than a first
predetermined fraction of a battery voltage for the drug delivery device or if
a measurement of a low side voltage is
greater than a second predetermined fraction of the battery voltage; and
initiating a failure mode for the drug
delivery device if the analog validation of the switch fails.
[00045] In any of these methods, monitoring the switch may include
sequentially sampling a switch input,
storing a window of sequential samples, and comparing a plurality of more
recent sequential samples to a plurality
of older sequential samples within the stored window of samples to detect the
release event. Monitoring the switch
may include sequentially sampling a switch input, storing a window of
sequential samples, and comparing three or
more recent sequential samples to three or more older sequential samples
within the stored window of samples to
detect the release event. As discussed above, initiating the failure mode may
include turning off the delivery device,
and/or inactivating the delivery device. Further, any of these methods may
include re-starting a button sampling
process of the drug delivery device if the digital validation of the switch
fails.
[00046] Performing the digital validation may include failing the digital
validation if a secondary digital input
on a first side of the switch does not match a primary digital input on the
first side of the switch, or a secondary
digital input on a second side of the switch does not match a primary digital
input on the second side of the switch;
and/or failing the analog validation if a measurement of a high side voltage
is less about 0.8 times a battery voltage
for the drug delivery device, or a measurement of a low side voltage is
greater than about 0.2 time the battery
voltage. Performing the analog validation may include sequentially measuring a
high side voltage and a low side
voltage using an analog to digital converter (ADC) and failing the analog
validation if the high side voltage is below
a first predetermined threshold or the low side voltage is above a second
predetermined threshold.
[00047] In general, a release event may include a second release of the
switch within a predetermined time
period. For example, a release event may include a second release of the
switch within less than about 100 msec.
INCORPORATION BY REFERENCE
[00048] All publications and patent applications mentioned in this
specification are herein incorporated by
reference in their entirety to the same extent as if each individual
publication or patent application was specifically
and individually indicated to be incorporated by reference.
BRIEF DESCRIPTION OF THE DRAWINGS
[00049] The novel features of the invention are set forth with
particularity in the appended claims. A better
understanding of the features and advantages of the present invention will be
obtained by reference to the following
detailed description that sets forth illustrative embodiments, in which the
principles of the invention are utilized, and
the accompanying drawings of which:
[00050] FIG. 1 illustrates an exemplary therapeutic agent delivery system;
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[00051] FIG. 2 shows an embodiment of iontophoretic therapeutic agent
delivery mechanism;
[00052] FIG. 3 shows an exemplary embodiment of a controller as connected
to an activation switch;
[00053] FIG. 4 shows exemplary timing of an activation sequence;
[00054] FIG. 5 is an exemplary embodiment of a therapeutic agent delivery
device having switch integrity
testing;
[00055] FIG. 6 is an exemplary embodiment of a therapeutic agent delivery
device with switch integrity
testing;
[00056] FIG. 7 shows exemplary timing of an activation sequence with
switch integrity testing;;
[00057] FIG. 8 shows an equivalent circuit configuration of therapeutic
agent delivery device 500 during a
short interval switch grounding integrity test;
[00058] FIG. 9 shows signaling during the short interval switch grounding
integrity test;
[00059] FIG. 10 shows an equivalent circuit configuration of therapeutic
agent delivery device 500 during a
short interval power switch integrity test;
[00060] FIG. 11 shows signaling during the short interval power switch
integrity test;
[00061] FIG. 12 shows an equivalent circuit configuration of therapeutic
agent delivery device 500 during a
long interval analog switch grounding integrity test;
[00062] FIG. 13 shows signaling during the long interval analog switch
grounding integrity test;
[00063] FIG. 14 shows an equivalent circuit configuration of therapeutic
agent delivery device 500 during a
long interval analog power switch integrity test;
[00064] FIG. 15 shows signaling during the long interval analog power
switch integrity test;
[00065] FIG. 16 shows a flow chart of the dosing operation of an
embodiment of a therapeutic agent delivery
device with switch integrity testing; and
[00066] FIG. 17 shows an exemplary embodiment of a switch integrity
testing process.
[00067] FIG. 18A shows a schematic illustration of one variation of a
switch and control circuitry for
performing both digital and analog validation.
[00068] FIG. 18B is a table describing connections of the nodes from the
example in FIG. 18A.
[00069] FIGS. 19A, 19B and 19C illustrates variations of the timing of
dose switch activation sequences for an
apparatus or method in which both analog and digital switch validation is
performed within the predetermined time
period immediately following a second manual switch actuation. FIGS. 19A, 19B
and 19C show analog switch
validation followed by digital switch validation, digital switch validation
followed by analog validation and
concurrent analog and digital switch validation, respectively.
DETAILED DESCRIPTION
[00070] Embodiments described herein provide circuitry and methods for
actively detecting faults and
precursors to faults in devices, such as drug delivery devices, and more
particularly iontophoretic drug delivery
devices.
[00071] In some embodiments, there is provided a switch operated device,
such as a drug delivery device (e.g.
a drug delivery pump, electrotransport device or iontophoresis device). The
device comprises (a) a device switch
configured to be operated by a user, which provides a switch signal to a
switch input of a device controller when
operated by a user; (b) the device controller, having said switch input
operatively connected to the switch, and
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configured to receive the switch signal from the switch, the device controller
being configured to actuate the device
when the switch signal meets certain predetermined conditions; and (c) a
switch integrity test subcircuit, which is
configured to detect a fault or a precursor to a fault in the switch, whereby
the controller executes a switch fault
subroutine when a fault or a precursor to a fault is detected. When the device
is an iontophoretic drug delivery
device, the device further comprises other circuitry components, such as
electrodes, one or more drug also called
active reservoirs and one or more counter ion reservoirs which are capable of
delivering drug to a patent in response
to patient input. An iontophoretic drug delivery device (iontophoresis
devices) is illustrated below, though
iontophoresis is well-characterized and is described in detail in US 7027859,
for example.
[00072] In some embodiments, the switch integrity test subcircuit is
configured to check for and detect a fault
or a precursor to a fault in the switch or connecting circuitry. In some
preferred embodiments, the act of checking
for a fault or precursor to a fault includes setting a circuit condition to
evoke a response in the circuit (for example,
change in voltage, change in current) which is expected to fall within
predetermined parameters if the circuit and its
components are free of faults or precursors to faults. In some embodiments,
the switch integrity test subcircuit is
configured to test for and detect at least one fault or precursor to a fault,
such as a member of the group selected
from the group consisting of contamination, shorts, (including intermittent
short circuits), compromised circuit
components (including malfunctioning resistors, integrated circuit pins or
interfaces, and/or capacitors), etc. Among
the advantages of the device and methods described herein, there may be
mentioned the ability to detect and respond
to precursors to faults before they manifest in such a manner as to cause the
device to malfunction in a way to
compromise patient comfort, safety and/or compliance. This aspect of device
and methods is described in more
detail herein, but includes the ability to actively test for and detect subtle
deviations in circuit characteristics from
predetermined normal circuit characteristics.
[00073] In some embodiments, the switch integrity test subcircuit is
configured to test for and detect a voltage
or change in voltage in between a short between the switch input and ground or
some intermediate voltage above
ground (low voltage, VL), a short between the switch input and a voltage pull
up or some intermediate voltage below
a pull up voltage (high voltage, VH). In some preferred embodiments, the
switch integrity test subcircuit is
configured to test for and detect a voltage or change in voltage in between a
short between the switch input and
some intermediate voltage above ground (low voltage, VL) and/or a short
between the switch input and intermediate
voltage below a pull up voltage (high voltage, VH) Thus, the switch integrity
test subcircuit is configured to test for
and detect a damaged circuit resistor, contamination (e.g., humidity,
particulates), corrosion and/or a damaged
integrated circuit pin or integrated circuit interfaces, etc.. In particular
embodiments, the switch integrity test
subcircuit includes the controller and additional circuit components under
control of the controller, which the
controller is capable of placing in certain states to cause certain effects in
the circuit. By detecting the effects that
arise when the controller places the circuit components in those predetermined
states, and comparing the effects to
those which are considered normal for the device, the controller can detect
faults and precursors to faults in the
device circuitry. It is a particular advantage of the instant device and
methods that precursors to faults may be
detected before they have manifested in such a way that their effects would be
experienced by a patient.
[00074] When the switch integrity test subcircuit detects a fault or a
precursor to a fault, it provides a fault
signal to the controller, which in turn executes a switch fauit subroutine,
which includes, for example, at least one
of: activating a user alert feature, logging detection of faults or precursors
to faults, deactivating the device, or one
or more combinations thereof. The user alert feature can include a variety of
means to alert a user that operation of
the system is considered compromised. Since the device is configured, in some
embodiments, to detect precursors to
faults, the device may activate the user alert even before a fault has been
detected that would cause an effect that
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would be experienced by the patient. The user alert may be an indicator light,
such as a colored light emitting diode
(LED), an audible tone (such as a repeating "beep"), a readable display (such
as a liquid crystal display (LCD)),
other user observable indicator (such as a text message, email, voicemail, or
other electronic message sent to a
device that is observable by the patient, the caregiver or both), or
combinations of two or more thereof.
[00075] As used herein, unless otherwise defined or limited, the term
"when" indicates that a subsequent event
occurs at the same time as or at some time after a predicate event. For the
sake of clarity, "switch integrity test
subcircuit detects a fault or a precursor to a fault, it provides a fault
signal to the controller, which in turn executes a
switch fault subroutine ..." is intended to indicate that the subsequent act
of executing the switch fault subroutine
happens as a consequence of (e.g., at the time of, or at some time after) the
predicate event of detection of the fault
or precursor to the fault. The term "when" is intended to have analogous
effect throughout this disclosure unless
otherwise indicated.
[00076] In some embodiments, the controller can also log detection of
faults or precursors to faults in memory,
such as flash memory. In some such embodiments, the controller detects a
certain type of fault, assigns it a fault
code, and records the fault code in memory for retrieval at a later time. For
instance, the controller may detect and
record one of the following conditions: a low voltage at a point and under
conditions where a high voltage would be
expected for a normally operating circuit; a voltage at a point and under
conditions that is higher or lower than the
voltage that would be expected for a normally operating circuit; a voltage
rise time that is longer or shorter than
would be expected for a normally operating circuit; a voltage fall time that
is longer or shorter than would be
expected for a normally operating circuit; or combinations of two or more
thereof.
[00077] In some embodiments, the switch fault subroutine includes
deactivating the device. Methods of
deactivating a device, e.g. by irreversibly decoupling the voltage supply from
the drug delivery circuit, shorting a
power cell to ground, fusing a fusible link in the circuit, etc., are known.
In some embodiments, the circuitry and
methods employed in United States Patent No. 7,027,859, which incorporated
herein by reference, especially those
recited between line 65 of column 6 and line 12 of column 8 of United States
Patent No. 7,027,859 (and the
accompanying figures) may be adapted to disable the circuit when the
controller detects a voltage or current, or
change thereof, that is outside of predetermined parameters.
[00078] In some preferred embodiments, devices and methods taught herein
will be capable of performing two
or more of the functions of activating a user alert feature (e.g. activating a
light and/or audible sound), logging the
detected fault or precursor to a fault, and/or deactivating a device. In some
preferred embodiments, the devices and
methods taught herein are capable of activating a user alert feature,
deactivating the device and optionally logging
the detected fault or precursor to a fault.
[00079] In some embodiments, the controller is configured to measure a
voltage or a rate of change of voltage
at the switch input and execute the switch fault subroutine when the voltage
or rate of change of voltage at the
switch input fails to meet one or more predetermined parameters. In some
embodiments, the device is an
iontophoresis delivery device comprising first and second electrodes and
reservoirs, at least one of the reservoirs
containing therapeutic agent to be delivered by iontophoresis. It is to be
understood that the terms "higher" and
"lower" are relative. Especially in embodiments in which the device is capable
of detecting and responding to
precursors to faults, the terms "higher" and "lower" may express deviations of
as little as 10%, 5%, 2% or 1% of the
expected values. For example, in terms of voltages, a voltage that is higher
than expected may be greater than from
10-200 mV, 10-100 mV, 10-50 mV, 20-200 mV, 20-100 mV, 20-50 mV, 50-200 mV, 50-
100 mV, or 100-200 mV
higher than the nominal voltage expected at the point and under the conditions
tested. In particular, the "higher"
voltage may be greater than 10 mV, 20 mV, 50 mV, 75 mV, 100 mV, 125 mV, 150
mV, 175 mV, 200 mV or 250
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mV than would be expected at the same point under the conditions tested. Also
in terms of voltages, a voltage that is
lower than expected may be at least from 10-200 mV, 10-100 mV, 10-50 mV, 20-
200 mV, 20-100 mV, 20-50 mV,
50-200 mV, 50-100 mV, or 100-200 mV lower than the voltage expected at the
point and under the conditions
tested. In particular, the "lower" voltage may be at least 10 mV, 20 mV, 50
mV, 75 mV, 100 mV, 125 mV, 150 mV,
175 mV, 200 mV or 250 mV less than would be expected at the same point under
the conditions tested. Voltage rise
and fall times may be characterized in the amount of time necessary (e.g.,
measured in ms or [is) for a point under a
condition tested to achieve an expected voltage state. In terms of rise or
fall times, the difference in rise or fall time
from the expected rise or fall time may be as little as 1 ms or as much as 20
ms, e.g. 1, 2, 5, 10, 12.5, 15 or 20 ms,
depending upon the point tested under the particular conditions. Voltage and
current rise times may also be
characterized by measuring a change in voltage or current between two selected
time points and comparing them to
the change in voltage or current that would be expected for a normally
operating circuit at the point and under the
condition tested.
[00080] In some preferred embodiments, the device is capable of detecting
subtle differences in circuit states ¨
whether voltages, currents, changes in voltages or changes in currents. These
subtle changes may indicate that the
circuit board has been contaminated with one or more contaminants, is
experiencing intermittent shorts between
circuit components, has one or more compromised circuit components, or
combinations thereof. Such embodiments
permit the device to identify precursors to faults before they manifest as
circuit faults that can affect delivery of a
drug and in particular before they are noticed by, or affect, a patient.
[00081] In some embodiments, the predetermined conditions for actuating
the device include the user
activating the switch at least two times within a predetermined period of
time. This feature permits the device to
distinguish between purposeful activation of the switch by a user (patient or
caregiver, preferably a patient) and
spurious or accidental button pushes, e.g. those that occur during shipping or
storage, those that occur from
contamination, or those that may accidentally occur during placement of the
device on the patient or during
movement of the patient after the device has been applied to the patient.
Activation of the switch by multiple button
pushes or the like is described with reference to the figures herein. The time
between button pushes ¨which is
typically on the order of at least a few hundred milliseconds (ms) ¨ affords
one time window during which the
device controller can actively test the switch circuit. In some embodiments,
the device is configured such that the
device will initiate drug delivery when it receives two distinct button pushes
of a predetermined separation in time ¨
e.g. on the order of 100 ¨400 ms, preferably about 300 ms. During this period,
which may be referred to as the test
period, the controller can actively set certain circuit parameters (using the
switch integrity test subcircuit), test
voltages or changes in voltages at certain points and compare them to
predetermined values that are indicative of
what a normally operating circuit ¨ i.e. a circuit that is not manifesting a
fault or a precursor to a fault ¨ would
manifest. For example, the controller may set a switch input to a low state
and remove a high supply voltage (VDD),
then check whether the switch input achieves a true low (expected) of 0 mV
above the low supply voltage (Vss, e.g.,
ground or some voltage above ground), or if it fails to achieve such a true
low (indicating a fault or precursor to a
fault) of at least 5 mV to at least 250 mV above Vss (e.g. at least 5, 10, 15,
20, 25, 30, 35, 40, 45, 50, 75, 100, 125,
150, 200, 225 or 250 mV above Vss). If a fault or precursor to a fault is
detected, the device controller will then
initiate a switch fault subroutine, as described elsewhere herein.
[00082] As used herein, VDD refers to any predetermined high voltage
(VH), and need not be the highest voltage
available from the power supply. Likewise, Vss refers to any predetermined low
voltage (VL) and need not indicate
"ground". Among other advantages, one advantage of the device and method
described herein is that intermediate
voltages may be used to test switch integrity, which allows for detection of
spurious voltages that indicate
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contaminants (e.g. humidity, particulates, corrosion, etc.) and other faults
and precursors to faults. The precise
values of VDD and Vss are selected by the artisan during device design.
[00083] In other exemplary embodiments, for example, the controller may
set a switch input to a VDD (e.g. a
value of from 2 V to 15 V, such as 5 V or 10 V) and connect the switch input
to Vss (e.g. a value of 0 V to 1 V
above ground), then check whether the switch input achieves VDD (as expected),
or if it fails to achieve VDD
(indicating a fault or precursor to a fault) by at least 5 mV to at least 250
mV lower than VDD (e.g. at least 5, 10, 15,
20, 25, 30, 35, 40, 45, 50, 75, 100, 125, 150, 200, 225 or 250 mV lower than
VDD).
[00084] In some embodiments, the switch input is pulled up to VDD when the
switch is open and the switch
input is Vss when the switch is closed. Other configurations are possible. For
example, with a change in the logic of
the controller, the switch input could be biased to Vss, meaning that upon a
button push the switch input would be
pulled high. The person of skill in the art will recognize that other
configurations, including those requiring three,
four or more sequential button pushes may be employed, though in general the
inventors consider two to be
sufficient for most purposes.
[00085] Some embodiments described herein provide a method of switch fault
detection in a switch operated
device, said device comprising: (a) a device switch connected to a switch
input of a device controller; (b) the device
controller comprising said switch input; and (c) a switch integrity test
subcircuit, said method comprising said
controller: (i) activating the switch integrity test subcircuit; (ii)
detecting a voltage condition at the switch input; and
(iii) activating a switch fault subroutine if the voltage condition at the
switch input fails to meet one or more
predetermined conditions. These methods may be carried out using for example
those circuits and devices described
herein.
[00086] In some embodiments, the steps of activating the switch integrity
test subcircuit and detecting a voltage
condition at the switch input are executed continuously or periodically
throughout operation of the device. Without
limitation, such a method may include digital or analog testing. Digital
testing is relatively fast and is well-suited to
performance during the test period between button pushes. Analog testing may
be either fast or slow, depending
upon how many data points are collected. Analog testing may be, and in some
embodiments is, more sensitive and is
well-adapted for detection of very subtle deviations from expected device
parameters which are symptomatic of
precursors to faults. Fast analog testing is well-suited for detection after
any button bounce or anything (any voltage
signal) that looks like (could be interpreted by the controller as) a button
push. Analog testing is also well-suited for
the period when drug is being delivered to a patient (that is after the second
button press in the case where the device
is activated by two distinct button presses) or even during the period between
drug delivery intervals (that is when
the device is still attached to the patient but is not currently delivering
drug). In the latter case, the device may
administer a very small amount of current for a brief period of time (e.g. 500
ms to 10 seconds, more preferably 500
ms to 5 seconds, even more preferably 500 ms to 1 second) during which time
the controller carries out its active
checking. As described herein, analog checking, whether between button pushes,
during the dosing period or
between dosing periods, is very sensitive and may detect subtle changes in
circuit properties before they develop
into full-fledged faults, thus permitting avoidance of untoward events before
they can manifest. In some
embodiments, testing may include a combination of digital and analog testing.
In some preferred embodiments, a
fast analog test is conducted after any button push (including detection by
the controller of any voltage signal that it
interprets as a button push) and/or a digital test is conducted after a second
button push. In some preferred
embodiments, a fast analog test is conducted after any button push (including
detection by the controller of any
voltage signal that it interprets as a button push) and a digital test is
conducted after a second button push. In some
embodiments, a slow analog test is conducted in addition to the digital test
sometime after the second button push.
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[00087] Some embodiments described herein provide a switch operated
iontophoresis therapeutic agent
delivery device, comprising: (a) a power source; (b) first and second
electrodes and reservoirs, at least one of the
reservoirs containing the therapeutic agent; (c) a device switch, which
provides a switch signal to a switch input of a
device controller when operated by a user; the device controller having said
switch input operatively connected to
the switch, whereby the controller receives the switch signal from the switch,
the device controller being operatively
connected to a power source that provides power to the first and second
electrodes for delivering therapeutic agent
to a patient; and (d) a switch integrity test subcircuit, which is configured
to detect a fault in the switch and cause the
controller to execute a switch fault subroutine when a fault is detected. In
some embodiments, the therapeutic agent
is fentanyl or sufentanil. For the sake of clarity, "fentanyl" includes
pharmaceutically acceptable salts of fentanyl,
such as fentanyl hydrochloride and "sufentanil" includes pharmaceutically
acceptable salts of sufentanil.
[00088] Some embodiments described herein provide a method of switch
fault detection in a user operated
iontophoresis therapeutic agent delivery device, said device comprising: (a) a
power source; (b) first and second
electrodes and reservoirs, at least one of the reservoirs containing the
therapeutic agent; (c) a device switch
connected to a switch input of a device controller; (d) the device controller
comprising said switch input and
configured to control power to the first and second electrodes, thereby
controlling delivery of the therapeutic agent;
and (e) a switch integrity test subcircuit, said method comprising said
controller: (i) activating the switch integrity
test subcircuit; detecting a voltage condition at the switch input; and (ii)
activating a switch fault subroutine if the
voltage condition at the switch input fails to meet one or more predetermined
conditions. In some embodiments, the
switch fault subroutine includes activating a user alert, deactivating the
device, or both.
[00089] The present invention relates generally to apparatus (e.g.,
electrical circuits) which are used to enhance
the safety of electrophoretic drug delivery. Drugs having particular potential
for use iontophoretic drug delivery
include natural and synthetic narcotics. Representative of such substances
are, without limitation, analgesic agents
such as fentanyl, sufentanil, carfentanil, lofentanil, alfentanil,
hydromorphone, oxycodone, propoxyphene,
pentazocine, methadone, tilidine, butorphanol, buprenorphine, levorphanol,
codeine, oxymorphone, meperidine,
dihydrocodeinone and cocaine. In the context of iontophoresis, it is to be
understood that when reference is made to
a drug, unless otherwise stated, it is intended to include all
pharmaceutically acceptable salts of the drug substance.
For example, where reference is made to fentanyl, the inventors intend that
term to include fentanyl salts that are
suitable for delivery by iontophoresis, such as fentanyl hydrochloride. Other
exemplary pharmaceutically acceptable
salts will be apparent to the person having ordinary skill in the art.
[00090] For the sake of clarity, as used herein, the terms "therapeutic
agent" and "drug" are used
synonymously, and include both approved drugs and agents which, when
administered to a subject, are expected to
elicit a therapeutically beneficial effect. For the sake of further clarity,
where a particular drug or therapeutic agent is
recited, it is intended that that recitation include the therapeutically
effective salts of those therapeutic agents.
[00091] Reference is now made to the figures, which illustrate particular
exemplary embodiments of the device
and methods taught herein. The person having skill in the art will recognize
that modifications and various
arrangements of the illustrated circuits and methods are within the scope of
the instant disclosure and claims.
[00092] FIG. 1 illustrates an exemplary therapeutic agent delivery
system. Therapeutic agent delivery system
100 comprises activation switch 102, controller 104 and therapeutic agent
delivery mechanism 106. Activation
switch 102 can be selected from a variety of switch types, such as push
buttons switch, slide switches and rocker
switches. In some embodiments, a push button switch is used. Though either a
"momentary on" or "momentary off"
push button switch can be used, for the sake of clarity, a momentary on push
button switch is given in each example.
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Controller 104 controls the administration of drugs to the patient as to the
specific rate and amount a drug is
dispensed. It can also be used to regulate the dosing interval. For example,
for a pain medication, the controller
could allow a patient to receive a dose at most once in a predetermined time
period, e.g. once every five minutes, ten
minutes, 15 minutes, 20 minutes, one hour or two hours. Controller 104 can
also comprise a power source, such as a
battery, or can simply regulate a power source external to the controller.
Typically, the power source controlled by
controller 104 is used to drive the delivery of the therapeutic agent through
therapeutic agent delivery mechanism
106. Controller 104 can be implemented in a number of ways known in the art.
It can comprise a microprocessor
and memory containing instructions. Alternatively, it can comprise an
appropriately programmed field-
programmable gate array (FPGA). It can be implemented in discreet logic or in
an application specific integrated
circuit (ASIC).
[00093] Therapeutic agent delivery mechanism 106 call be selected from a
variety of dosing mechanisms
including iontophoresis and IV-line pumps. In the former case, a small
electric charge which is controlled by
controller 104 is used to deliver a drug through a patient's skin. In the
latter case, the controller 104 controls a pump
which introduces the drug into an intravenous line. For the sake of clarity,
the examples herein refer to an
iontophoretic drug dispenser.
[00094] FIG. 2 shows an embodiment of iontophoretic therapeutic agent
delivery mechanism. Iontophoretic
therapeutic agent delivery mechanism 200 comprises active electrode 202,
active reservoir 204, return electrode
212, counter ion reservoir 214. Active electrode 202 and return electrode 212
are electrically coupled to controller
104. Iontophoretic therapeutic delivery agent delivery mechanism 200 often
takes the form of a patch which is
attached to the skin of a patient (220). Active reservoir 204 contains ionic
therapeutic agent 206, which can be a
drug, medicament or other therapeutic agent as described herein and has the
same polarity as the active electrode.
Counter ion reservoir 214 contains counter ion agent 216, which is an ionic
agent of the opposite polarity as the
ionic therapeutic agent which can be saline or an electrolyte. In other
embodiments, iontophoretic therapeutic
delivery mechanism 200 can further comprise additional active and/or counter
ion reservoirs.
[00095] When controller 104 applies a voltage across active electrode 202
and return electrode 212, the
patient's body completes a circuit. The electric field generated in this
fashion conducts ionic therapeutic agent 206
from active reservoir 204 into the patient. In this example, controller 104
comprises power supply 240 which can be
a battery. In other embodiments controller 104 controls an external power
source. Therapeutic agent delivery
mechanism 200 often comprises a biocompatible material, such as textiles or
polymers, which are well known in the
art as well as an adhesive for attaching it to a patient's skin.
[00096] In some embodiments, controller 104 and iontophoretic therapeutic
agent delivery mechanism 200 are
assembled together at the time of application of the therapeutic agent. This
packaging permits ready application and
insures the integrity of the therapeutic agent, but can also introduce
addition points of failure of the delivery device.
[00097] Therapeutic agent delivery system 100 is often used in
circumstances which allow a patient to self-
administer drug. For example, an analgesic agent (such as fentanyl or
sufentanil, especially in form of a
hydrochloride or other deliverable salt) may be self-administered using such a
device. In such a circumstance, a
patient can self-administer the analgesic agent whenever he feels pain, or
whenever the patient's pain exceeds the
patient's pain tolerance threshold. Numerous safeguards and safety features
are incorporated into controller 104, in
order to ensure the patient's safety. In order to ensure proper delivery in an
iontophoretic therapeutic agent delivery
system, the device may be configured to take into account the varying
resistance of the patient's skin among other
elements in the circuit. Thus, controller 104 can regulate the amount of
current delivered to the patient in order to
permit consistent delivery of the therapeutic agent, by monitoring the current
(e.g., by measuring the voltage across
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a current sensing resistor) and adjusting the voltage up or down accordingly.
Furthermore, if the condition of the
voltage supply prevents proper operation (e.g., weak battery), the device can
shut down.
[00098] In operation, it is often convenient for the patient who is not
acquainted with the particulars of drug
application, and who may also be in painful distress, to allow a button press
to activate the delivery of the
therapeutic agent. Controller 104 upon activation can administer a single dose
at the prescribed rate. To prevent
inadvertent dosing, controller 104 can require the patient to activate
activation switch 102 twice within a
predetermined interval. As previously described, a predetermined test period
interval can be used to insure that a
single switch activation attempt by the patient is not incorrectly interpreted
as two switch activation attempts. As
described herein, this test period interval provides one convenient period
during which a device as described herein
can detect and respond to a fault or a precursor to a fault, e.g. using an
analog or digital fault checking method.
[00099] FIG. 3 shows an exemplary embodiment of a controller as connected
to an activation switch.
Activation switch 302 is shown as a push button momentary "on" switch and is
coupled to the ground plane and to
controller 300 through switch input 308. Controller 300 comprises pull up
resistor 304 and control circuit 306. Pull
up resistor 304 is coupled to a supply voltage VDD and switch input 308.
Control circuit 306 is also coupled to
switch input 308. When activation switch 302 is open, pull up resistor 304
pulls the voltage at switch input 308 to
the level of the supply voltage VDD. When the activation switch 302 is closed,
it pulls the voltage at switch input 308
down to ground.
[000100] Although for the sake of illustration reference is made here to VDD
Vss and "ground" it is to be
understood that wherever reference is made to VDD, unless otherwise specified,
this is intended to include any
predetermined logic level high (VH). Likewise, wherever reference is made to
Vss or "ground", it is intended, unless
otherwise specified, to include any predetermined logic level low (VL). In
some preferred embodiments, the logic
high level is an intermediate voltage below VDD and/or the logic low level is
some intermediate voltage above
ground. In some preferred embodiments, in fact, the logic high level is an
intermediate voltage below VDD and the
logic low level is some intermediate voltage above ground. For the sake of
clarity, in some places herein the logic
high may be referred to as VH and the logic low may be referred to as VL. The
use of VH below VDD and/or VI., above
ground (or Vss) permits the detection of indeterminate voltage signals that
arise out of contamination, corrosion or
other faults and precursors to faults.
[000101] FIG. 4 shows exemplary timing of an activation sequence. Trace 400
shows a plot of voltage at the
switch input as a function of time. At time 402, the push button is depressed
causing the voltage at switch input 308
to drop to the ground potential. At time 404, the push button is released
causing the voltage at switch input 308 to
return to the supply voltage level. To further enhance the robustness of the
activation of the device, controller 300
enforces a predetermined minimum time interval 406 and a predetermined maximum
time interval 412 between the
release of the button after the first button press and the second pressing of
the button. Should a button press occur
before predetermined minimum time interval 406 has elapsed, it is ignored, as
during this period it is not clear as to
whether a second button press was intended or not. This interval is long
enough to avoid an accidental reading, but
sufficiently short that an average patient would have a difficult time
pressing the button faster than the
predetermined minimum time interval. Exemplary predetermined minimum time
intervals are given in the overview
discussed above. At time 408, which occurs after predetermined minimum time
interval has elapsed, a second button
press occurs, followed by a button release at time 410. Upon validating the
second button press after time 410,
controller 300 accepts the sequence as a valid activation sequence and the
delivery of the therapeutic agent can
begin, provided the second button press is completed before the predetermined
maximum time interval has elapsed,
for example within 3 seconds. This ensures that an accidental first button
press does not leave the therapeutic agent
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delivery device armed so a second accidental button press could activate the
delivery of the therapeutic agent. The
activation sequence ensures the therapeutic agent is not delivered
accidentally. In addition to ensuring that the
therapeutic agent is only delivered when the patient desires it, controller
300 can also incorporate logic and/or
circuitry which prevent over-dosing of the therapeutic agent as well as
prevent the dispensing of the therapeutic
agent after a predetermined lifetime. Such logic and circuitry are described
for instance in US 7027859, which is
incorporated by reference in its entirety, especially as described elsewhere
herein. Again, although VDD and Vss are
used for illustrative purposes in FIG. 4, any logical high (VH) can be used
instead of VDD and any logical low (VL)
can be used instead of Vss. In some embodiments VH < VDD or VL > Vss. In some
embodiments VH < VDD and VL >
Vss
[000102] Additional safeguards to ensure the integrity of the switch can also
be implemented into controller 300.
For example, controller 300 can detect whether there is a short (including an
intermittent short) between switch 302
and either the ground plane or a power supply trace, which can result from
contamination or corrosion. The short
circuit can be a "hard" short or an intermittent short. Shorts, including
intermittent shorts, can be caused by, for
example, corrosion or contamination on the circuit. The corrosion or
contamination can provide an electrical
pathway, which may be continuous or spurious. Additionally, controller 300 can
detect whether there is damage to
the switch input, which could be an integrated circuit pin or integrated
circuit interface pad. A short due to
contamination or corrosion, especially an intermittent short, may not
necessarily cause the device to malfunction per
se. Initially, the contamination or corrosion can manifest itself in a high
resistance path between switch 302 and the
ground plane or power supply trace; but over time, as the contamination or
corrosion accumulates, the resistance of
this path may decrease until ultimately the switch may fail. Therefore, the
presence of even a high resistance short is
indicative of a future fault. Accordingly, in some embodiments, the controller
will detect intermittent shorts such as
those described and initiate a suitable switch fault subroutine, as described
herein. For example, the switch fault
subroutine may include setting one or more suitable user alerts (e.g. and
audible tone or a visible indicator) and/or
disabling the device (e.g. by disconnecting the power supply from the
electrodes).
[000103] FIG. 5 is an exemplary embodiment of a therapeutic agent delivery
device embodying switch integrity
testing. Like controller 300, controller 510 comprises control logic 306, pull
up resistor 304, and switch input 308.
Controller 510 further comprises a switch integrity test subcircuit comprising
switch 502 (which can be used to
electrically decouple pull up resistor 304 from switch input 308), switch
integrity test output 506 and integrity test
sublogic 512 within control logic 306. Switch integrity test subcircuit is
activated when switch integrity testing is
performed. Integrity test sublogic 512 is configured to open switch 502 and
set switch integrity output 506 to a
predetermined voltage or sequence of voltages in accordance with a particular
switch integrity test. In an
implementation where controller 510 resides on an integrated circuit, switch
integrity test output 506 can be
implemented with a general purpose I/O port or an analog input pin. Switch
integrity test output 506 is coupled to
switch input 308 with resistor 504 which generally has a high resistance
(e.g., 1 Me). Switch integrity test output
506 can be left floating, can provide a high supply voltage (VD0) or can
provide a low supply voltage (Vss) (e.g.,
ground potential). During testing, switch 502 is opened electrically,
decoupling pull up resistor 304 from switch
input 308. Depending on the desired test, switch integrity test output 506
provides a high supply voltage or a low
supply voltage. Greater detail is given in the following description. For
clarity integrity test sublogic 512 is omitted
from further diagrams. Again, although VDD and ground are used for
illustrative purposes in FIG. 5, any logical high
(VH) can be used instead of VDD and any logical low (VL) can be used instead
of ground. In some embodiments VII <
VDD or VL > ground. In some embodiments VH < VDD and VL > ground
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[000104] FIG. 6 is an exemplary embodiment of a therapeutic agent delivery
device with switch integrity
testing. More specifically, controller 510 and more specifically integrity
sublogic 512 (not shown) comprises switch
604 and switch 606 which are controlled by control logic 602. When switch 604
and switch 606 are open switch
integrity test output 506 is left floating. When switch 604 is closed and
switch 606 is open, switch integrity test
output 506 provides a high supply voltage. When switch 604 is open and switch
606 is closed, switch integrity test
output 506 provides a low supply voltage. Again, although VDD and ground are
used for illustrative purposes in FIG.
6, any logical high (VH) can be used instead of VDD and any logical low (VL)
can be used instead of ground. In some
embodiments VH < VDD or VL > ground. In some embodiments VH < VDD and VL >
ground.
[000105] A variety of tests can be performed in this configuration. Referring
to FIG. 7, due to the double button
press safeguards against accidental dosing, there are several opportunities to
apply switch integrity testing. After a
button release at time 404, switch 302 is ignored until predetermined minimum
time interval 406 has elapsed, during
this period the integrity of switch 302 and its interfaces can be tested. As
long as the test takes less than the
minimum time interval 406, a short test (e.g. a fast analog test or a digital
test) can be performed. In some
embodiments, a fast analog test is performed. Depicted in FIG. 7 is time span
702 which is the time a short test can
be performed. After the second button release at time 410, another test (e.g.
a digital or a fast or slow analog test)
can take place during the delivery of the therapeutic agent, because during
this period of time any signal by switch
302 can be ignored. The second test is depicted in FIG. 7 during time span
704. Again, although VDD and Vss are
used for illustrative purposes in FIG. 7, any logical high (VH) can be used
instead of VDD and any logical low (VL)
can be used instead of Vss. In some embodiments VH < VDD or VL > Vss. In some
embodiments VH < VDD and VL >
vss
[000106] FIG. 8 shows an equivalent circuit configuration of therapeutic agent
delivery device 500 during a
short interval switch grounding integrity test. During the short interval
switch test, switch integrity test output 506 is
forced from a high supply voltage state to a low supply voltage state,
depicted in FIG. 8 as grounding resistor 504.
Additionally switch 502 is opened during the test. During the test resistor
504 acts as a pull down resistor causing
the voltage at switch input 308 to drop from VDD to Vss. The rate at which the
voltage falls is based on the
resistance-capacitance ("RC") time constant. The resistance in the circuit is
furnished by resistor 504 and the
capacitance is the capacitance inherent in switch input 308 and circuitry. For
example, if controller 510 is
implemented in an ASIC mounted to a printed circuit board (PCB), metal traces
in the PCB, interface pins, balls or
lands in the ASIC package can be major sources of capacitance. Due to
experimentation, a nominal capacitance of
controller 510 can be determined. Any deviation in the observed decay rate of
the voltage seen at switch input 308
can result from resistor 504 being bad, contamination, shorts, open circuits
("opens"), missing or bad PCB traces, or
a bad ASIC interface. For example, electrostatic discharge (ESD) during
manufacturing, packaging, storage or use
could damage the ASIC interface. Again, although VDD and ground are used for
illustrative purposes in FIG. 8, any
logical high (VH) can be used instead of VDD and any logical low (VL) can be
used instead of ground. In some
embodiments VH < VDD or VL > ground. In some embodiments VH < VDD and VL >
ground
[000107] FIG. 9 shows signaling during the short interval switch grounding
integrity test. Signal trace 902 is the
signal from integrity switch test output 506 which initially begins at VDD and
drops abruptly to Vss. Signal trace 904
is the signal observed at switch input 308 for a "good" therapeutic agent
delivery device. After predetermined time
interval 910 has elapsed after the drop in the voltage of integrity switch
test output 506, the signal has decayed to a
known value as indicated by arrow 912. However, if the after predetermined
time interval 910, the signal as shown
by signal trace 906 observed at switch input 308 does not decay as rapidly as
expected, to the known value as
indicated by arrow 914, there may be excess capacitance or resistance in the
test circuit which could indicate the
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existence of a fault or a precursor of a fault as described above. Again,
although VD0 and Vss are used for illustrative
purposes in FIG. 9, any logical high (VH) can be used instead of VDD and any
logical low (VL) can be used instead of
Vss. In some embodiments VH < VDD or VL > Vss. In some embodiments VH < VDD
and VL > Vss
[000108] FIG. 10 shows an equivalent circuit configuration of therapeutic
agent delivery device 500 during a
short interval power switch integrity test. During the short interval switch
test, switch integrity test output 506 is
forced from a low supply voltage state to a high supply voltage state,
depicted in FIG. 10. Once again switch 502 is
opened during the test. During the test, resistor 504 acts as a pull up
resistor causing the voltage at switch input 308
to rise from Vss to VDD. The rate at which the voltage rises is based on the
RC time constant, similar to that
described above for the short interval switch grounding integrity test. Once
again, the causes of deviation from the
nominal RC time constant described above can result from resistor 504 being
bad, contamination, shorts, opens,
missing or bad PCB traces, or a bad ASIC interface. Again, although VDD and
ground are used for illustrative
purposes in FIG. 10, any logical high (VH) can be used instead of VDD and any
logical low (VL) can be used instead
of ground. In some embodiments VH < VDD or VL > ground. In some embodiments VD
< VDD and VL > ground
[000109] FIG. 11 shows signaling during the short interval power switch
integrity test. The signal is logically
complementary to that depicted in FIG. 9. Signal trace 1102 is the signal from
integrity switch test output 506 which
initially begins at Vss and rises abruptly to VDD. Signal trace 1104 is the
signal observed at switch input 308 for a
"good" therapeutic agent delivery device. After predetermined time interval
1110 has elapsed after the drop in the
voltage of integrity switch test output 506, the signal has risen to a known
value as indicated by arrow 1112.
However, if the after predetermined time interval 910, the signal as shown by
signal trace 906 observed at switch
input 308 does not rise as rapidly as expected, to the known value as
indicated by arrow 1114, there may be excess
capacitance or resistance in the test circuit which could indicate the
existence of a fault or a precursor of a fault as
described above. It is noted that where testing is conducted after a second
button push, e.g. as in some embodiments
employing digital testing, there need not be any timing element; and in some
such embodiments there is no timing
element. Again, although VDD and Vss are used for illustrative purposes in
FIG. 11, any logical high (VH) can be
used instead of VDD and any logical low (VL) can be used instead of Vss. In
some embodiments VH < VDD Or VL >
Vss. In some embodiments VH < VDD and VL > Vss
[000110] FIG. 12 shows an equivalent circuit configuration of therapeutic
agent delivery device 500 during an
analog switch grounding integrity test. The equivalent circuit configuration
shown in FIG. 12 is essentially the same
configuration as that depicted in FIG. 8. Additionally control logic 306
further comprises a means for measuring the
voltage at switch input 308. In the depicted embodiment, the means for
measuring voltage is analog to digital
converter ("ADC") 1204, however other methods for measuring voltage can be
implemented, such as the use of a set
of comparator circuits in place of the ADC to measure the voltage level of the
analog signal compared to a
comparator threshold. As in FIG. 8, switch integrity test output 506 is forced
down to a low supply voltage state, so
resistor 504 acts as a pull down resistor. If contamination or corrosion
(shown as 1202) exists between switch 302,
switch input 308 or connecting wirings and a high power supply source such as
a power line metal trace, the
contamination or corrosion may act as a resistor pulling up against resistor
504 resulting in a voltage divider. The
result is that resistor 504 would not be able to completely pull down the
voltage at switch input 308 down to Vss. If
the voltage that switch input 308 fails to settle at Vss, then contamination,
corrosion or other corruption of the
apparatus is causing a short between the switch 302 and/or switch input 308
and a high power supply source. Again,
although VDD and Vss are used for illustrative purposes in FIG. 12, any
logical high (VH) can be used instead of VDD
and any logical low (VL) can be used instead of Vss. In some embodiments VH <
VDD or VL > Vss. In some
embodiments VH < VDD and VL > Vss
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[000111] FIG. 13 shows signaling during the long interval analog switch
grounding integrity test. (Although
reference is made to a long interval analog grounding integrity test, the test
may be made short interval by adjusting
the number of data points collected.) Signal trace 1302 is the signal from
integrity switch test output 506 which
initially begins at VDD and drops abruptly to Vss. Signal trace 1304 is the
signal observed at switch input 308 for a
"good" therapeutic agent delivery device. After predetermined time interval
1310 has elapsed after the drop in the
voltage of integrity switch test output 506, the signal has decayed to its
final value. Predetermined interval 1310
differs from predetermined interval 910 shown in FIG. 9. Because the objective
of the short interval test is to
measure the rate of decay, predetermined interval 910 should be short enough
so that any change in the RC time
constant would be observed. In contrast, predetermined interval 1310 should be
long enough so that the signal
observed at switch input 308 should have decayed to a steady state voltage
regardless of the RC time constant (or at
least within a reasonable range of RC time constants). Signal trace 1306 is
the signal observed at switch input 308
for a therapeutic delivery agent when corruption or some other source causes a
short between a high power supply
and switch 302 and/or switch input 308. The discrepancy between the steady
state voltage and Vss is indicated by
arrow 1308. Again, although VDD and Vss are used for illustrative purposes in
FIG. 13, any logical high (VH) can be
used instead of VDD and any logical low (VL) can be used instead of Vss. In
some embodiments VH < VDD or VL >
Vss. In some embodiments V14 < VDD and VL > Vss
[000112] Operationally, after predetermined time interval 1310, control logic
306 measures the voltage at switch
input 308. If the steady state voltage exceeds a given threshold, a fault can
be indicated by controller 510.
Additionally or alternatively, if the steady state voltage exceeds a second
threshold a precursor to a fault can be
indicated and appropriate action can be taken by controller 510.
[000113] FIG. 14 shows an equivalent circuit configuration of therapeutic
agent delivery device 500 during a
long interval analog power switch integrity test. The equivalent circuit
configuration shown in FIG. 14 is essentially
the same configuration as that depicted in FIG. 10. Once again control logic
306 further comprises a means for
measuring the voltage at switch input 308. As in FIG. 10, switch integrity
test output 506 is forced up to a high
supply voltage state, so resistor 504 acts as a pull up resistor. If
contamination or corrosion (shown as 1402) exists
between switch 302, switch input 308 or connecting wirings and a low power
supply source such as a ground trace,
or if contamination or corrosion intrudes between the two poles on switch 302
causing switch 302 to short, the
contamination or corrosion may act as a resistor pulling down against resistor
504 resulting in a voltage divider. The
result is that resistor 504 would not be able to completely pull up the
voltage at switch input 308 up to VDD. If the
voltage that switch input 308 fails to settle at VDD, then contamination,
corrosion or other corruption of the apparatus
is causing a short to a low power supply source. Again, although VDD and Vss
are used for illustrative purposes in
FIG. 14, any logical high (VH) can be used instead of VDD and any logical low
(VL) can be used instead of Vss. In
some embodiments VH < VDD or VL > Vss. In some embodiments VH < VDD and VL >
Vss.
[000114] FIG. 15 shows signaling during the long interval analog power switch
integrity test. Signal trace 1502
is the signal from integrity switch test output 506 which initially begins at
Vss and rises abruptly to VDD. Signal
trace 1504 is the signal observed at switch input 308 for a "good" therapeutic
agent delivery device. After
predetermined time interval 1510 has elapsed after the rise in the voltage of
integrity switch test output 506, the
signal has risen to its final value. Once again, predetermined interval 1510
differs from predetermined interval 1110
shown in FIG. 11, for reasons similar to the difference between predetermined
interval 1310 and predetermined
interval 910. Signal trace 1506 is the signal observed at switch input 308 for
a therapeutic delivery agent when
corruption or some other source causes a short between a low power supply and
switch 302 and/or switch input 308.
The discrepancy between the steady state voltage and VDD is indicated by arrow
1508. Again, although VDD and Vss
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are used for illustrative purposes in FIG. 15, any logical high (V0) can be
used instead of VDD and any logical low
(VL) can be used instead of Vss. In some embodiments VH < VDD or VL> Vss. In
some embodiments VH < VDD and
VL > Vss.
[000115] Operationally, after predetermined time interval 1510, control logic
306 measures the voltage at switch
input 308. If the voltage differential between the steady state voltage and
VDD exceeds a given threshold, a fault can
be indicated by controller 510. Additionally or alternatively, if the voltage
differential exceeds a second threshold a
precursor to a fault can be indicated and appropriate action can be taken by
controller 510.
[000116] FIG. 16 shows a flow chart of the dosing operation of an embodiment
of a therapeutic agent delivery
device with switch integrity testing. At step 1602, the device waits for a
button release. This corresponds to waiting
for event 404 in FIG. 7. At step 1604 after the button has been released one
or more short switch integrity tests can
be performed such as those described above in FIGS. 8-11. At step 1606, the
device waits for a second button
release. After the button has been released, at step 1608, a determination is
made as to whether the second button
press has occurred within the predetermined minimum time interval. If it has
not, the last button release is ignored
and the device returns to step 1606 where it waits for another button release.
If it has, a determination is made as to
whether the maximum time interval since the first button release has elapsed.
If it has, the second button release is
treated as the first hence the device returns to step 1604. If the maximum
time has not elapsed, at step 1612, delivery
of the therapeutic agent begins. (Although not specifically depicted in FIG.
16, it is to be understood that one or
more switch integrity checks may be performed between step 1610 and step 1612,
such as a digital switch integrity
check or a fast analog integrity check.) Concurrently with delivery of
therapeutic agent, the device can perform one
or more optional long switch integrity tests at step 1614. . Concurrently, a
determination is made at step 1616 as to
whether a fault with sufficient severity to warrant the shutdr.wn of the
device has occurred. If so the device shuts
down at step 1618.
[000117] FIG. 17 shows exemplary embodiment of a switch integrity testing
process. The flowchart shown is
representative of typical switch integrity processes which be used in steps
1604 and/or step 1614. At step 1702,
device 500 activates its switch integrity subcircuit. In the examples given
above, this can include opening switch
502, setting the switch integrity test output to a predetermined voltage such
as VDD or Vss and/or optionally
powering on or activating ADC 1204 such as in the configurations shown in
FIGS. 12 and 14. In some
embodiments, the ADC circuitry could be powered off when not testing to save
power. At step 1704, one or more
predetermined voltage conditions are tested for. Examples of these conditions
are described above in FIGS. 8-15.
For example, in the short tests described in FIGS. 8-11, after a predetermined
time interval has elapsed after the
switch integrity test output is set to the predetermined voltage, the voltage
at switch input 308 is measured. If the
measured voltage has risen or decayed to the expected voltage, a voltage
condition is deemed to be detected. In
another example, in the long tests described in FIGS. 12-16, after a
predetermined time interval has elapsed after the
switch integrity test output is set to the predetermined voltage, the voltage
at switch input 308 is measured. If a
discrepancy exists between the predetermined voltage and the measured voltage
then a voltage condition is deemed
to be detected.
[000118] At step 1706 a determination is made as to whether a predetermined
voltage condition was detected, if
so at step 1708 a fault subroutine is activated. More specifically, each
predetermined voltage condition is associated
with a fault or a precursor to a fault. The fault subroutine can take one or
more courses of action depending on the
severity of the fault or precursor to a fault. For example, the patient or
care provider can be alerted by activating a
user alert feature. As previously discussed, the user alert feature can
include a variety of means to alert a user that
operation of the system is considered compromised. In some embodiments, the
device is configured to detect
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precursors to faults, so the device may activate the user alert even before a
fault has been detected that would cause
an effect that would be experienced by the patient. The user alert may be an
indicator light, such as a colored light
emitting diode (LED), an audible tone (such as a repeating "beep"), a readable
display (such as a liquid crystal
display (LCD)), other user observable indicator, communications to an external
monitoring device, (e.g., a wireless
transmission to a central console) or combinations of two or more thereof.
[000119] In another example, the faults and precursors to faults can be logged
in memory. In some such
embodiments, the controller detects a certain type of fault, assigns it a
fault code, and records the fault code in
memory for retrieval at a later time. For instance, the contreller may detect
and record one of the following
conditions: a low voltage at a point and under conditions where a high voltage
would be expected for a normally
operating circuit; a voltage at a point and under conditions that is higher or
lower than the voltage that would be
expected for a normally operating circuit; a voltage rise time that is longer
or shorter than would be expected for a
normally operating circuit; a voltage or current fall time that is longer or
shorter than would be expected for a
normally operating circuit; or combinations of two or more thereof. The logs
can be retrieved in several ways, for
example it may be retrieved by a removable memory medium such as flash memory,
viewed by a care provider by
one or more visual messages on a display device, or transmitted to an external
monitoring device.
[000120] In another example, when the faults have sufficient severity pose a
risk to a patient, the device can be
deactivated such as by irreversibly decoupling the voltage supply from the
drug delivery circuit, shorting a power
cell to ground, fusing a fusible link in the circuit, by means of software
logic, etc., as described herein.
[000121] In another example, the fault subroutine can perform a combination of
the actions described. For
example, initially, precursors to faults are logged, but as the severity of
the potential faults increases, a user alert is
issued. Finally, when potential faults become actual faults and the severity
is sufficiently high, the device shuts
down at step 1618.
[000122] If no voltage condition is found at step 1706 or after the voltage
condition is processed at step 1708,
optionally the switch integrity process can proceed to step 1710 where either
the device prepares for the next test or
prepares to end the final test. In the former case, the device may set the
switch integrity test output to another
voltage. For example, in preparation for one of the grounding tests described
above in FIGS. 8-9, 12-13, the switch
integrity test output could be set to VDD so that when the grounding tests
begins in step 1702 the switch integrity test
output can be driven down to Vss to initiate the test. However, this can be
minimized by proper selection of tests.
For example, if the power tests and the ground tests are alternated, there is
no need to set the switch integrity test
output to another voltage as each tests leaves the switch integrity test
output in the appropriate voltage to initiate the
other test. In the latter case at step 1710, the device can deactivate the
switch integrity subcircuit, for example the
switch integrity test output can be set to its non-test default state which
can be either the high supply voltage or the
low supply voltage. Alternatively, the switch integrity test output could be
left floating. Additionally switch 502 is
closed so that resistor 304 can resume its pull up function.
[000123] As described above, any of the apparatuses and methods described
herein may be configured to
perform both analog and digital switch validation of the dose switch. FIG. 18A
illustrates one example of a circuit
description for a drug delivery device that performs both analog and digital
switch validation.
[000124] For example, a normally-open switch (e.g., a momentary-contact push-
button switch) (SW1) is
located in the circuit. In FIG. 18A, the SW1 switch is located on the IT101
circuit board, and is referred to as the
dose switch. Each side of the switch is directly connected to three separate
lines on the circuit (IC), which contains
the control logic. The Auxl, KPO and GPIO0 lines are on one side of the dose
switch and Aux2, KP3, and GPIO2
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are on the other side of the dose switch. These connections allow the
controller (e.g., "ITSIC") to confirm that the
dose switch is operating properly. Any appropriate dose switch may be used.
For example, the dose switch may be
a mechanical switch configured as a button having a round metal snap dome,
with a characteristically short contact
bounce. No electrical de-bouncing is required for such an example, although
switches with electrical de-bouncing
could be used. FIGS. 18A and 18B show the dose switch connection design and
descriptions of nodes.
[000125] For example, in FIG. 18A, the high side of the switch ("A") includes
nodes for the first power input
line (KPO), the first digital test input line (GPI0_0), the first analog test
input line (AUX1). The low side of the
switch ("B") includes nodes for the second power input line (KP3), the second
digital test input line (GPI0_1), and
the second analog test input line (AUX2). The battery (Vbat) is also shown
connected to the KPO and KP3 lines,
including pull-up resistors (Rpu0 and Rpu3). The analog and digital test input
lines all connect to the controller
(ITSIC) where they be analyzed to perform the digital validation (using GPIOO
and GPI0_1) and analog validation
(using AUX1 and AUX2). In this example the same controller/processor is used;
different processors, including
sub-processors, may be used.
[000126] Three separate techniques (procedures) may provide redundancy and
enable demonstration of the
validation method to a high degree of certainty, particularly when all three
are employed and integrated as part of
the apparatus. Specifically, button sampling, analog switch validation, and
digital switch validation may all be
included.
[000127] Button sampling (including a button sampling procedure) may be used
to detect button pressing and
release. In particular, button sampling may include the use series of
sequential state tests to determine when the
button is in a stable configuration (e.g., pressed or released) by comparing
sequential samples taken over a short
period of time. Rapid changes in the state indicate that the button is not in
a stable ("pushed" or "released") state.
For example, to detect transitions of a button input and to filter out noise
signals caused by switch bounce or other
events, button inputs may be sampled periodically, e.g., every n ms (e.g.,
where n may be 2 ms, 3 ms, 4 ms, 5 ms, 6
ms, 7 ms, 8 ms, 9 ms, 10 ms, between about 1-20 ms, 1-10 ms, 2-10 ms, etc.).
The sampling frequency may provide
responsiveness to user inputs. The sampled data (button input sample data) may
be buffered into a circular buffer
that holds a predetermined number of samples (e.g., 4 samples, 5 samples, 6
samples, 7 samples, 8 samples, 9
samples, 10 samples, 11 samples, 12 samples, 13 samples, etc.). The most
recent samples (e.g., the four most recent
samples) may be used by a button sampling test (which may be implemented in
hardware, software, firmware, or
some combination thereof) to determine the state of the button. The state of
the button is determined (e.g., as open
or closed) when all of the most recent samples (e.g., all four samples) are
the same state. This distinguishes a stable
button state from a mechanical switch bounce or electrical noise. If the
buffer contains a mix of low and high
sample values, the signal may be determined to be a result of switch bounce or
electrical noise and the apparatus
may ignore the signal.
[000128] Press and release transitions may be detected, and upon each
transition, the state of the buttons may be
sampled (e.g., at a rate of approximately 50ms). For example, a release
transition may be confirmed by detection of
four depressed states flowed by four released states, and a press transition
may be confirmed by the opposite
sequence. If the button is sampled every 8 ms and 4 samples are examined
within the rolling window, the result is
approximately 65 ms of sampling time to identify a valid button state
transition.
[000129] Using two separate switch validation techniques/pathways (e.g.,
analog and digital switch validation)
may provide redundancy and enable demonstration of the validation to a high
degree of certainty in a way that is
surprisingly better than a single validation technique/path. The analog switch
validation test and the digital switch
validation test are both performed, or may both be performed; in some
variations both tests are performed only
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when one of the test is performed first and passes (e.g., is true). For
example, the analog switch validation may be
performed only if the digital switch validation is true, or vice/versa.
[000130] The controller, which may include firmware, hardware and/or software,
typically controls and
monitors the dose switch circuit using both digital and analog signals. An
analog portion of the dose switch circuit
may be used to monitor analog voltages on both sides of the dose switch (e.g.,
the high, "A", and low, "B", sides).
A digital portion of the dose switch circuit may be used for switch bias
control and digital monitoring on both sides
of the switch. In the example shown in FIG. 18A, software may configure the
keypad input pull-up KPO and
GPIO[1] to establish a Vbat bias across the switch 1802, as shown. KP3 and
GPIO[0] may be used to monitor the
digital state of the switch.
[000131] An analog switch validation test may measure the voltage levels on
both the high and low sides of the
dose button switch in order to detect potential problems that could lead to
erroneous switch readings. Under normal
conditions with the switch open, voltage on the high side of the switch will
be slightly less than battery voltage, after
accounting for the small voltage drop caused by the electronic components
connected to the switch circuit. Under
normal conditions, the voltage on the low side of the switch will be very
close to ground. Some conditions, such as
contamination or corrosion, can cause the high-side voltage to drop, or the
low-side voltage to rise. If the high-side
voltage falls to less than a predetermined high-side threshold, such as some
predetermined high-side fraction of the
battery voltage (e.g., 0.8 x battery voltage), or the low-side voltage rises
to greater than some predetermined low-
side threshold, such as a predetermined low-side fraction of the battery
voltage (e.g., 0.2 x battery voltage), then the
switch input may fall in a range of indeterminate digital logic level with
respect to the digital switch input. A switch
voltage in this range could result in erroneous switch readings, which could
manifest as false button transitions that
were not initiated by the user, and therefore improper dosage. An analog
switch validation test may therefore detect
a condition before the switch voltage levels reach the point where erroneous
readings could occur.
[000132] The analog switch validation test may be run when the switch is in
its normally-open condition, so that
the high- and low-side voltages can both be measured. Any change in the switch
state while the test is running
could cause the test to falsely fail due to measurement of the high-side
voltage while the switch is closed. Since a
user may press or release the button at any time, the apparatus may be
configured to run the test in such a way to
avoid interference with normal operation, e.g., allowing a button push, or
more likely a pair of button pushes, at any
time without interfering with the analog and/or digital switch validation. The
apparatus and methods described
herein may take advantage of the fact that there are mechanical and human
limits on the minimum time between
button presses, and thus the point where the switch state is known to be open
with the greatest certainty is
immediately following a detected release of the button. Thus the analog and/or
digital switch validation may be
performed following one or more button pushing events, or more likely button
release events.
[000133] For example, an analog switch validation test may be performed
immediately following the second
button release of a double-press that meets the criteria for a dose initiation
sequence. An analog switch validation
may use an analog-to-digital converter (ADC), e.g., part of the
controller/processor (e.g., ITSIC), to make sequential
measurements of the high-side voltage and the low-side voltage. For example,
an ADC may be configured to
sample for 6.25 ms for each measurement. If the voltage on the high side of
the switch is less than or equal to the
high side predetermined threshold (e.g., 0.8 x battery voltage), or if the
voltage on the low side is greater than or
equal to the low side predetermined threshold (e.g., 0.2 x battery voltage),
the test fails. The switch high and low
limits may be calculated and stored each time the battery voltage is measured
for a battery voltage test.
[000134] A digital switch validation test is generally also performed by the
apparatus and methods describe
herein. A digital switch validation test may be similar in purpose to the
analog switch validation test, but is
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generally simpler, faster, and coarser in its measurements. The test may use
secondary digital inputs (e.g., GPIO[0]
and GPIO[1] in FIGS. 18A and 18B), connected to each side of the dose switch
1802, to confirm the digital logic
levels while the switch is open (e.g., button not depressed). These
"secondary" digital inputs (e.g., first and second
digital test input lines) may be of the same type as the primary digital
inputs, and the corresponding values of these
digital inputs are expected to match. For example, the first (high side)
digital input test line should have the same
logical value as the first input line connected to the battery and the second
(low side) digital input test line should
have the same logical value as the second input line.
[000135] The digital switch validation test may be run either before, during
or after an analog switch validation
test. The performance of the analog switch validation test may depend on a
successful digital switch validation test,
or vice versa. For example, an analog switch validation test may be performed
after a successful digital switch
validation test following the second button release of a double-press that
meets the criteria for a dose initiation
sequence. For example, if the secondary digital input on the high side of the
switch is low, or if the secondary
digital input on the low side of the switch is high, the digital switch
validation test fails, and the system may initiate
a failure mode (e.g., a digital switch validation failure mode); if the
secondary digital input on the high side of the
switch is high, and if the secondary digital input on the low side of the
switch is low, the digital switch validation
test passes, and the system may then perform an analog switch validation, as
described above. If the analog switch
validation test fails, then the system may also initiate a failure mode (e.g.,
an analog switch validation failure mode).
The failure mode may include locking the device (to prevent further
activations), shutting the device down,
restarting the device, issuing an alert/warning (e.g., buzzer, alarm, etc.),
disconnecting the battery from the circuit,
or some combination of these. For example, if the analog switch validation
test fails, the apparatus may enter into
an end of life mode.
[000136] FIGS. 19A-19C illustrate variations on the timing of a dose switch
activation sequence for an
apparatus or method that is configured to perform both analog and digital
switch validation tests. In FIGS. 19A-
19C, following a second activation of a dose switch within a predetermined
time period 1902, both the switch
validation tests are performed. In FIG. 19A, the analog switch validation
(ASV) test is performed first, followed by
the digital switch validation (DSV) test. The digital switch validation test
may be performed if the analog switch
validation test is good (e.g., if the high and low sides of the switch are
within the acceptable voltage ranges set by
the predetermined thresholds (e.g., > 0.8xVbat on the high side and <0.2Vbat
on the low side). Both the analog and
the digital switch validation tests may be performed within a window of time
following release of the switch (e.g.,
following the second release within a switching time period'. The window of
time may begin immediately or
shortly after detecting the release of the switch and extend for a period of
time during which it is impossible or
highly unlikely that a subject could push the button again. For example the
switch validation tests may be
performed before the test period (test window) has ended (e.g., 500 ms, 400
ms, 300 ms, 200 ms, 150 ms, 100 ms,
50 ms, etc.).
[000137] In FIG. 19B, the digital switch validation (DSV) test is performed
first, followed by the analog switch
validation (ASV) test. For example, the analog switch validation may be
performed only if the digital switch
validation passes (e.g., the high side is a logical 1 and/or matches the high-
side voltage input from the first input line
connected to the battery, and the low side is a logical 0 and/or matches the
low-side voltage input from the opposite
input line). If the digital switch validation does not pass, the device may
enter a first failure mode (e.g., restarting,
and/or incrementing a counter or flag indicating failure of the digital switch
validation, shutting down, etc.). If the
digital switch validation passes, and the subsequent analog switch validation
passes, then the dose may be delivered;
however, if the digital switch validation passes but the analog switch
validation does not pass, then the device may
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CA 02949709 2016-11-18
WO 2015/187834 PCT/US2015/033990
enter into a second failure mode (e.g., shutting the device down, restarting
the device, issuing an alert/warning,
disconnecting the battery from the circuit, or some combination of these). The
first and second failure modes may
be the same. In some variations, the first and second failure modes are
different. For example, if the digital switch
validation test fails, the software may ignore that dose request and remains
in Ready mode (first failure mode), and
if the analog switch validation test fails, the apparatus may enter into an
end of life failure mode (EOL mode). In
some variations, the analog switch validation test is more sensitive (e.g.,
uses more sensitive circuitry) than the
digital switch validation test. Passing the analog switch validation test may
indicate that the circuitry is intact;
failure of the analog switch validation test may indicate a failure of the
circuitry. In such instances, failure of the
analog switch validation test may therefore cause the apparatus to enter into
EOL (end of life) mode. Passing the
digital switch validation test may also (redundantly) indicate that the
circuitry is intact, but failure of the digital
switch validation test may not necessarily indicate failure of the circuitry.
Failure of the digital switch validation
test may also be a result of temporary electrical noise signals. Performing
the analog switch validation test before
the digital switch validation test may therefore prevent false positive
failures of the digital switch validation test
from disabling the system by entry to EOL mode.
[000138] FIG. 19C illustrates another variation in which the analog and
digital switch validation modes are
performed at the same time, or approximately the same timf, following the
second release of the does switch
detected during the allowable time period (e.g., the time period when to
activations of the does switch indicate a
dose is requested).
[000139] When a feature or element is herein referred to as being "on" another
feature or element, it can be
directly on the other feature or element or intervening features and/or
elements may also be present. In contrast,
when a feature or element is referred to as being "directly on" another
feature or element, there are no intervening
features or elements present. It will also be understood that, when a feature
or element is referred to as being
"connected", "attached" or "coupled" to another feature or element, it can be
directly connected, attached or coupled
to the other feature or element or intervening features or elements may be
present. In contrast, when a feature or
element is referred to as being "directly connected", "directly attached" or
"directly coupled" to another feature or
element, there are no intervening features or elements present. Although
described or shown with respect to one
embodiment, the features and elements so described or shown can apply to other
embodiments. It will also be
appreciated by those of skill in the art that references to a structure or
feature that is disposed "adjacent" another
feature may have portions that overlap or underlie the adjacent feature.
[000140] Terminology used herein is for the purpose of describing particular
embodiments only and is not
intended to be limiting of the invention. For example, as used herein, the
singular forms "a", "an" and "the" are
intended to include the plural forms as well, unless the context clearly
indicates otherwise. It will be further
understood that the terms "comprises" and/or "comprising," when used in this
specification, specify the presence of
stated features, steps, operations, elements, and/or components, but do not
preclude the presence or addition of one
or more other features, steps, operations, elements, components, and/or groups
thereof. As used herein, the term
"and/or" includes any and all combinations of one or more of the associated
listed items and may be abbreviated as
V,.
[000141] Spatially relative terms, such as "under", "below", "lower", "over",
"upper" and the like, may be used
herein for ease of description to describe one element or feature's
relationship to another element(s) or feature(s) as
illustrated in the figures. It will be understood that the spatially relative
terms are intended to encompass different
orientations of the device in use or operation in addition to the orientation
depicted in the figures. For example, if a
device in the figures is inverted, elements described as "under" or "beneath"
other elements or features would then
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CA 02949709 2016-11-18
WO 2015/187834
PCT/US2015/033990
be oriented "over" the other elements or features. Thus, the exemplary term
"under" can encompass both an
orientation of over and under. The device may be otherwise oriented (rotated
90 degrees or at other orientations) and
the spatially relative descriptors used herein interpreted accordingly.
Similarly, the terms "upwardly",
"downwardly", "vertical", "horizontal" and the like are used herein for the
purpose of explanation only unless
specifically indicated otherwise.
[000142] Although the terms "first" and "second" may be used herein to
describe various features/elements,
these features/elements should not be limited by these terms, unless the
context indicates otherwise. These terms
may be used to distinguish one feature/element from another feature/element.
Thus, a first feature/element discussed
below could be termed a second feature/element, and similarly, a second
feature/element discussed below could be
termed a first feature/element without departing from the teachings of the
present invention.
[000143] As used herein in the specification and claims, including as used in
the examples and unless otherwise
expressly specified, all numbers may be read as if prefaced by the word
"about" or "approximately," even if the
term does not expressly appear. The phrase "about" or "approximately" may be
used when describing magnitude
and/or position to indicate that the value and/or position described is within
a reasonable expected range of values
and/or positions. For example, a numeric value may have a value that is +/-
0.1% of the stated value (or range of
values), +/- 1% of the stated value (or range of values), +/- 2% of the stated
value (or range of values), +/- 5% of the
stated value (or range of values), +/- 10% of the stated value (or range of
values), etc. Any numerical range recited
herein is intended to include all sub-ranges subsumed therein.
[000144] Although various illustrative embodiments are described above, any of
a number of changes may be
made to various embodiments without departing from the scope of the invention
as described by the claims. For
example, the order in which various described method steps are performed may
often be changed in alternative
embodiments, and in other alternative embodiments one or more method steps may
be skipped altogether. Optional
features of various device and system embodiments may be included in some
embodiments and not in others.
Therefore, the foregoing description is provided primarily for exemplary
purposes and should not be interpreted to
limit the scope of the invention as it is set forth in the claims.
[000145] The examples and illustrations included herein show, by way of
illustration and not of limitation,
specific embodiments in which the subject matter may be practiced. As
mentioned, other embodiments may be
utilized and derived there from, such that structural and logical
substitutions and changes may be made without
departing from the scope of this disclosure. Such embodiments of the inventive
subject matter may be referred to
herein individually or collectively by the term "invention" merely for
convenience and without intending to
voluntarily limit the scope of this application to any single invention or
inventive concept, if more than one is, in
fact, disclosed. Thus, although specific embodiments have been illustrated and
described herein, any arrangement
calculated to achieve the same purpose may be substituted for the specific
embodiments shown. This disclosure is
intended to cover any and all adaptations or variations of various
embodiments. Combinations of the above
embodiments, and other embodiments not specifically described herein, will be
apparent to those of skill in the art
upon reviewing the above description.
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Representative Drawing

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Administrative Status

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Administrative Status

Title Date
Forecasted Issue Date Unavailable
(86) PCT Filing Date 2015-06-03
(87) PCT Publication Date 2015-12-10
(85) National Entry 2016-11-18
Dead Application 2020-08-31

Abandonment History

Abandonment Date Reason Reinstatement Date
2018-06-04 FAILURE TO PAY APPLICATION MAINTENANCE FEE 2019-01-07
2019-06-03 FAILURE TO PAY APPLICATION MAINTENANCE FEE

Payment History

Fee Type Anniversary Year Due Date Amount Paid Paid Date
Registration of a document - section 124 $100.00 2016-11-18
Application Fee $400.00 2016-11-18
Maintenance Fee - Application - New Act 2 2017-06-05 $100.00 2017-05-29
Reinstatement: Failure to Pay Application Maintenance Fees $200.00 2019-01-07
Maintenance Fee - Application - New Act 3 2018-06-04 $100.00 2019-01-07
Owners on Record

Note: Records showing the ownership history in alphabetical order.

Current Owners on Record
INCLINE THERAPEUTICS, INC.
Past Owners on Record
None
Past Owners that do not appear in the "Owners on Record" listing will appear in other documentation within the application.
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Document
Description 
Date
(yyyy-mm-dd) 
Number of pages   Size of Image (KB) 
Abstract 2016-11-18 1 54
Claims 2016-11-18 3 163
Drawings 2016-11-18 19 377
Description 2016-11-18 29 2,483
Cover Page 2016-12-02 1 30
Patent Cooperation Treaty (PCT) 2016-11-18 2 74
International Search Report 2016-11-18 2 87
National Entry Request 2016-11-18 17 787