Note: Descriptions are shown in the official language in which they were submitted.
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SYSTEM AND APPARATUS WITH SELF-DIAGNOSTIC AND EMERGENCY
ALERT VOICE CAPABILITIES
[0001] Blank
FIELD OF THE INVENTION
[00021 The present invention relates generally to an emergency alert system
that
provides a voice alert when a possible emergency is detected where the voice
alert
includes information to enable the building occupants to quickly locate and
follow the
nearest path of egress out of a building. Additionally, the present invention
relates
generally to a self-diagnostic component of the emergency alert system that
provides
a voice alert when a problem is detected with the emergency alert system and
provides information on the problem detected.
BACKGROUND OF THE INVENTION
[0003] Emergency alert equipment is generally used in buildings, homes, and
other
structures and locations to notify building occupants of emergency conditions
existing
in or around the structure. Conventionally, the emergency alert equipment
includes a
plurality of alert devices located throughout the building with the ability to
provide an
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alert by sounding a loud noise and/or flashing bright lights when emergency
conditions are detected. Emergency conditions may be detected by sensors, such
as a
smoke detector, carbon monoxide detector, or temperature detector, located
throughout the structure or emergency switches that may be triggered by the
building
occupants upon observing an emergency condition. These sensors and triggers
are
typically in electrical communication with the alert device in order to notify
the alert
device when an emergency condition exists.
[0004] Emergency alert systems may also include emergency exit indicators that
are commonly located close to designated emergency exits and include an exit
sign
that illuminates when the emergency alert device is in an alert mode. In a
typical
emergency alert operation, the emergency exit sign flashes at a 1 Hz rate and
provides
a 1 Hz beep or other similar noise giving an audible indication of where the
exit is
located. Conventional emergency alert systems, however, simply emit tones from
buzzers and beepers and provide flashing lights. They do not provide any
useful
information to building occupants relating to the appropriate route to follow
in order
to evacuate the building. If a large amount of smoke or fire prevents building
occupants from seeing an emergency exit sign, the occupants may be unable to
find
an appropriate exit route.
[0005] Emergency alert systems also include a micro-controller for receiving
information concerning possible emergency conditions existing, the charge of
the
battery, condition of any emergency lamps and sound devices, circuitry
connecting
the various components of the emergency alert system, and the voltage level
from the
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building's electrical system. The micro-controller may also perform a self-
diagnostic
test on the emergency alert system's various components, including ensuring
that the
temperature, battery voltage, battery charger voltage, lamp and charge
current, and
the building's electrical power voltage stay within pre-set criteria levels.
If the self-
diagnostic test indicates that one or more of the tested values are outside
the pre-set
criteria levels, the emergency system may alert maintenance personnel or
building
occupants of the problems found during self-diagnostic testing. Conventional
methods for alerting maintenance personnel or building occupants include
displaying
flash codes with a light emitting diode (LED) display that may be correlated
by the
personnel or occupants to indicate the problem or sounding a beeper or buzzer
to
indicate that a problem has been detected by the self-diagnostic system.
[0006] Conventional emergency alert self-diagnostic systems, however, do not
clearly indicate the presence of component failures to personnel or occupants.
For
example, building occupants and building maintenance personnel are often
confused
by codes displayed on the LED display that indicate a problem with the
emergency
alert system. Furthermore, visual indicators, such as an LED display, often go
unnoticed because the emergency alert systems are located in remote areas of
the
building and building maintenance personnel do not perform routine checks of
the
emergency systems. Additionally, emergency alert systems are often located at
height levels that prevent the display from being observed. Beeps or buzzers
that
indicate a problem with the emergency alert system often confuse maintenance
personnel and building occupants since they fail to clearly indicate the type
of
problem being detected by the self-diagnostic system.
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.
[0007] Therefore, a need exists for an emergency alert system that provides
voice
notification and description of the problem detected by the self-diagnostic
component
and a voice alert that is activated during a detected emergency that provides
building
occupants with the ability to quickly locate and follow the nearest path of
egress out
of the building.
SUMMARY OF THE INVENTION
[0007a] In one aspect, the present invention provides an emergency alert
system
comprising a micro-controller configured to receive, through fire alarm
interface
circuitry from at least one emergency sensor of a plurality of emergency
sensors,
emergency condition input data comprising a type of a possible or actual
emergency
condition and a location with respect to the micro-controller of the possible
or actual
emergency condition. A voice alert system is provided in communication with
the
micro-controller and includes a voice storage with stored voice phrase data
comprising a
plurality of voice phrases comprising a first voice phrase including a
description of a
first exist path and a second voice phrase including a description of a second
exit path.
An audio amplifier is provided and is configured to receive voice phrase data
from the
voice storage. A phrase selection switch is configured to provide phrase
information to
the micro-controller. The micro-controller is configured to analyze phrase
information
and the emergency condition input data, select at least one of the plurality
of voice
phrases from the voice phrase data stored in the voice storage based on the
phrase
information and based on the type of the possible or actual emergency
condition and the
location with respect to the micro-controller of the possible or actual
emergency
condition, and command the voice storage to send the selected at least one of
the
plurality of voice phrases to the audio amplifier. The micro-controller is
further
configured to analyze data representing a level of noise in an area and send
commands
to the audio amplifier to control a volume of these selected at least one of
the plurality
of voice phrases based on the level of noise.
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[0007b] In another aspect, there is provided an emergency alert system having
a
plurality of self-diagnostic test points configured to automatically monitor
the
emergency alert system during operation of the emergency alert system and
detect,
based on monitoring the emergency alert system. A voice alert system is
provided and
comprises a plurality of voice phrases. A micro-controller is configured to
analyze the
diagnostic information and, based on the diagnostic information, to select at
least one
voice phrase from the plurality of voice phrases and send a command to the
voice alert
system to output the selected at least one voice phrase. The at least one
voice phrase
selected from the plurality of voice phrases provides information about the at
least one
problem associated with the emergency alert system. The micro-controller is
configured
to analyze data representing a level of noise in an area and send commands to
the audio
amplifier regarding volume of the selected at least one voice phrase based on
the level
of noise.
[0007c] In another aspect, the invention provides a method for providing an
audible
alert associated with an emergency alert system, the method comprising:
automatically
monitoring during operation of the emergency alert system for emergency
condition
input data and diagnostic information associated with the emergency alert
system,
wherein the emergency condition input data comprises a type of a possible or
actual
emergency condition and a location of the possible or actual emergency
condition with
respect to a micro-controller of the emergency alert system, wherein the
diagnostic
information comprises an indication of a possible or actual problem with the
emergency
alert system; detecting emergency condition input data or diagnostic
information;
selecting at least one voice phrase from stored plurality of voice phrases
based on at
least one of (a) the emergency condition input data comprising the type of the
possible
or actual emergency condition and the location of the possible or actual
emergency
condition with respect to the micro-controller; or (b) the diagnostic
information
comprising the indication of the possible or actual problem with the emergency
alert
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system; receiving data representing a level of noise in an area; amplifying
the selected at
least one voice phrase based on the data representing the level of noise in an
area; and
audibly outputting the selected at least one voice phrase, the selected at
least one voice
phrase comprising at least one of (i) directional information to direct
building occupants
away from the location of the possible or actual emergency condition with
respect to the
micro-controller or (ii) information about the possible or actual problem with
the
emergency alert system.
[0008] Certain exemplary embodiments of the present invention provide an
emergency alert system with sensors for detecting dangerous conditions inside
and/or
around a building and manually triggered switches for providing building
occupants
with the ability to provide the emergency alert system with notice that a
dangerous
condition may exist. The sensors may be able to detect the presence of smoke,
abnormally high temperatures, carbon monoxide, or any other condition that
might pose
a danger to life or property. The sensors and manually triggered switches may
be
electrically connected to one or more emergency alert devices and provide the
emergency alert devices an indication that a possible dangerous condition
exists. Once
the emergency alert devices receive the indication, they may provide a visual
and
audible alarm that notifies the building occupants of the possible presence of
a
dangerous condition.
[0009] In certain embodiments of the present invention, the emergency alert
devices include a micro-controller that contains information about the nearest
exit
path for building occupants and/or receives information related to the
presence, type,
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and location of a possible dangerous condition. The micro-controller may also
communicate with a programmable electronic voice storage device and send a
command that is correlated to certain voice audio content based on the
information
obtained concerning the presence, type, and location of a possible dangerous
condition and the nearest exit path. The electronic voice storage sends the
particular
voice audio through an audio amplifier that is controlled by the micro-
controller to a
speaker in order to be heard by the building occupants. The voice audio may
contain
instructions for building occupants concerning the location of the nearest
exit path
and the location and type of possible dangerous condition. The voice audio may
be
provided in addition to flashing lights and/or high volume noises to notify
building
occupants of the possible presence of a dangerous condition.
[00101 In some embodiments of the present invention, the micro-controller
receives information concerning the noise level existing around particular
location of
the emergency alert device. Depending on the noise level around the particular
emergency alert device, the micro-controller may manipulate the audio
amplifier to
ensure that the building occupants will hear the voice audio and/or other
audio
notification signal.
[00111 Certain other embodiments of this invention include emergency alert
devices with self-diagnostic capabilities. The self-diagnostic may be
performed by
self-diagnostic circuitry in the emergency alert devices. The self-diagnostic
circuitry
receives information concerning various measurable aspects of the entire
emergency
alert system, including the sensors and emergency alert devices, and compares
that
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information to pre-set criteria. Measurable aspects may include the
temperature,
battery voltage, battery charger voltage, lamp and charge current, and the
building's
electrical power voltage. A possible problem with the emergency alert system
is
indicated if the measurable information falls outside the pre-set criteria. If
a possible
problem is indicated, the self-diagnostic system provides the micro-controller
with
information concerning the problem. Such information may include the type and
location of the possible problem.
[00121 The micro-controller may convert the information into electrical
signals
representing a voice. The micro-controller may be programmed to send the
electrical
signal to an electronic voice storage device. The electronic voice storage may
convert
the electrical signals into an audible voice signal that relates to the type
and location
of the possible emergency alert system or light fixture problem. In addition,
the
electronic voice storage may receive and convert signals from the micro-
controller
relating to the existence of a possible problem with the emergency alert
system to a
voice audio. The electronic voice storage sends the information through an
audio
amplifier, controlled by the micro-controller, to a speaker in order to notify
building
occupants and maintenance personnel of a problem with the emergency alert
system.
For instance, the voice audio may initially announce that there is a problem
with the
emergency alert system and then indicate the type, such as a dead battery, and
location. Therefore, building occupants and/or maintenance personnel may be
quickly and accurately notified when a problem with the emergency alert system
arises.
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[0013] Advantages of certain aspects and embodiments of the present invention
include providing verbal announcements of possible problems detected by the
self-
diagnostic system. Additionally, certain aspects and embodiments provide
components that announce pre-selected information when the emergency alert
system
detects a possible emergency. Furthermore, certain aspects and embodiments of
the
present invention provide audio instructions and identification of the nearest
exit
and/or exit path during an emergency. Some embodiments may provide a
controllable circuitry that that may be manipulated, based on the surrounding
noise
level, to increase the volume of audio signals and voice messages such that
the
building occupants may hear any messages or audio signals from the emergency
alert
device. Finally, certain aspects and embodiments of the present invention
provide
audio information about a pre-selected path that is the nearest exit for
building
occupants.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure I schematically shows a block diagram of an emergency alert
system
according to one embodiment of the present invention.
[0015] Figure 2 is a simplified schematic illustrating certain features of the
system
shown in FIG. 1.
[0016] Figure 3 is a diagram illustrating the relationship of FIGS. 3A, 3B and
3C.
[0017] Figures 3A, 3B and 3C in combination form a schematic of a charger
circuit
utilized in the system shown in FIG. 1.
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[0018] Figure 4 is a schematic of a self-diagnostic option board.
[0019] Figure 5 is a diagram illustrating the relationship of FIGS. 5A, 5B and
5C.
[0020] Figures 5A, 5B, and 5C in combination form a schematic of a circuit
utilized in another embodiment of this invention.
DETAILED DESCRIPTION OF THE INVENTION
[0024] FIG. 1 shows one embodiment of a voice alert system 12 and self-
diagnostic system 14 along with the other components of an emergency alert
system
10. The emergency alert system 10 generally includes components that sense the
possible existence of emergency conditions, either automatically using sensors
or
manually using a switch operated by a human.
[0025] The emergency alert system 10 includes LED lamps 16 that preferably
form
an array of LED lights arranged in series. The LED lamps 16 are operated under
normal, non-emergency conditions through the power supply 19. One example of
such power supply 19 is a transformer or capacitor network that is used to
change the
building's electric alternating current (AC) power into direct current (DC)
power.
The system may also include normal line voltage circuitry 20 for sensing the
presence
of AC line voltage from the power supply 19 to the LED lights 16 through an
input
signal fed to the normal line voltage circuitry 20 from the power supply 19.
The
normal line voltage circuitry 20 then feeds a signal correlating to the
electric
parameters of the power supply 19 power to a micro-controller 22. The micro-
controller 22 controls boost converter 25 to supply power to the LED lamps 16
upon
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discontinuation of power from the power supply 19. Upon such a discontinuation
of
power from the power supply 19, a battery 26 provides power to the boost
converter
25. The micro-controller 22 also controls a battery charging circuit 28 by
changing
the battery charging circuit 28 between a "charging" state to a "standby"
state. The
micro-controller 22 is normally powered by the power supply 19 through a
regulator
circuit 30 and by the battery 26 through the boost converter 25 upon
discontinuation
of power from the power supply 19.
[0026] The emergency alert system 10 may also include DC lamps 33 for
additional illumination and notification when a possible emergency is
detected. The
DC lamps 33 are powered by the battery 26 and are controlled by the micro-
controller
22.
[0027] The micro-controller 22 receives input status indicator circuitry 34
and fire
alarm interface circuitry 37. The status indicator 34 may include an LED and
circuitry able to detect the operating status (i.e. on/off) of the emergency
alert system
and send the information to the micro-controller 22. The LED may provide
information such as whether the emergency alert system 10 is on or off. In
some
embodiments of the present invention, the fire alarm interface circuitry 37
receives
input signals from emergency sensors, such as a smoke detector, heat detector,
and
carbon monoxide detector, and manually triggered switches, all located
throughout
the building. These input signals may indicate the presence, location, or type
of
possible emergency conditions. The fire alarm interface circuitry 26 may send
the
received signals to the micro-controller 22 where the micro-controller 22 uses
the
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information to control other components of the emergency alert system 10 for
notifying building occupants of the possible emergency.
[0028] As stated above, the emergency alert system 10 also includes a voice
alert
system 12. The voice alert system 12 preferably provides voice information and
commands based on the signals from the fire alarm interface circuitry 37. For
instance, the micro-controller 22 receives a signal from the fire alarm
interface
circuitry 37 indicating a possible emergency. The micro-controller also
receives
information from a phrase selection switch 1202. Upon installation in a
building, the
phrase selection switch 1202 is set to the phrase applicable to the emergency
alert
system 10 placement and the nearest building exit. For instance, if the
nearest exit
requires building occupants to make a "left" at the particular emergency alert
system,
the installer will select the "turn left" phrase with the switch.
[0029] The micro-controller then sends the selected directional phrase and
commands to voice storage 1204, selecting additional phrases based on the
information from the fire alarm interface circuitry 37 and directing the voice
storage
1204 to send the voice phrases to an audio amplifier 1206. The audio amplifier
1206
controls the volume of the appropriate phrases from the voice storage 1204 and
phrase selection switch 1202 and is controlled by the micro-controller 22. The
audio
amplifier 1206 then sends the phrases to a speaker 1208, which broadcasts the
phrases
to the building occupants.
[0030] Examples of the types of voice phrases that may be used to alert
building
occupants include, "fire in the south kitchen, please turn left to exit,"
"smoke in the
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1St quadrant, please go straight ahead to exit," or just "exit right." There
are an
infinite number of phrases and commands that may be broadcast through the
speaker
by the voice alert system 12. Preferably, the voice phrases, except for exit
directional
commands, are stored in a digital format in the voice storage 1204 and sent to
the
audio amplifier 1206 based on commands from the micro-controller 22. The
phrase
selection switch 1202 preferably inputs a pre-determined phrase into the micro-
controller 22 upon the detection of a possible emergency. Alternatively, the
exit
commands are stored in the phrase selection switch 1202 and are accessed by
the
micro-controller upon the presence of a possible emergency. Alternatively, a
computer, based on information from the micro-controller 22, generates the
appropriate phrases.
[0031] The emergency alert system 10 further includes a self-diagnostic system
14
that detects when one or more components of the emergency alert system 10 is
not
operating properly and, along with the voice alert system 12, provides voice
information concerning the defective component. The self-diagnostic system
includes
any number of test points 1402a...1402n. The test points 1402a...1402n obtain
information related to whether the various components of the emergency alert
system
are working properly and may be located anywhere in the emergency alert system
10. For instance, the test points may obtain information concerning the
temperature
of the emergency alert system 10, the battery 26 voltage level, the battery
charging
circuitry 28 voltage level, the LED lamp 16 and battery charger 28 current
level, test
switch, and the AC line voltage level. The obtained information is sent by the
test
points 1402a...1402n to the micro-controller 22. The micro-controller 22
processes
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the information from the test points 1402a... 1402n and sends a command to the
voice
storage 1204 selecting the appropriate phrase with respect to the information
obtained
from the test points 1402a... 1402n and directing the voice storage 1204 to
send the
appropriate phrases to the audio amplifier 1206. The micro-controller 22
controls the
audio amplifier 1206, which can change the volume of the phrases. The audio
amplifier 1206 sends the voice phrases to the speaker 1208 in order for the
building
occupants to hear the information.
[0032] Examples of voice phrases used based on information from the self-
diagnostic system include "dead battery, please replace," "no AC voltage,
check
connection," or "no charging voltage, replace battery charging circuit." The
voice
information allows building maintenance personnel to quickly locate and fix
the
problem with the emergency alert system 10. There are an infinite number of
phrases
and commands related to self-diagnostic notification that may be broadcast
through
the speaker by the voice alert system 12. Preferably, the voice phrases are
stored in a
digital format in the voice storage 1204 and sent to the audio amplifier 1206
based on
commands from the micro-controller 22. The exit commands are stored in the
phrase
selection switch 1202 and are accessed by the micro-controller upon the
presence of a
possible emergency. Alternatively, a computer, based on information from the
micro-
controller 22, generates the appropriate phrases based on the particular
problem
detected by the self-diagnostic system 14.
[0033] In one embodiment of the present invention, the micro-controller 22
receives the level of noise in the area around its particular location. Based
on the
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level of surrounding noise, the micro-controller 22 increases or decreases the
volume
of the emergency or self-diagnostic notification volume with the audio
amplifier
1206. For example, if the noise in the area surrounding area around the
emergency
alert system 10 is high, the micro-controller 22 will adjust the audio
amplifier 1206
such that the emergency voice alerts or detected component problem
notifications are
higher in volume so they will be noticed by building occupants.
[0034] FIGs. 2-5c show components of an emergency alert system that may be
used by certain embodiments of the present invention. FIGs. 2-5c are also
described
in U.S. Patent No. 6,502,044, titled "Self-Diagnostic Circuitry for Emergency
Lighting Fixtures".
[0035] Referring now to FIG. 2, it is seen that a boost converter 24 is
comprised in
FIG. 2 of transistor 36, inductances 38 and 40, diode 42 and resistor 44. The
circuit
elements 36 through 44, coupled with batteries 46 and 48 which are preferably
NiCd
batteries, act to convert a low battery voltage to a higher voltage and are
thus capable
of driving a light emitting diode lamp 50. Such circuitry is disclosed in U.S.
Pat. No.
5,739,639. The light emitting diode lamp 50 comprises an array of light
emitting
diodes 52 configured in any desired manner including as configured in the
aforesaid
patent.
[0036] The transistor 36 is controlled in response to a software program
contained
in the microprocessor 18, this control of the transistor 36 being accomplished
through
the use of a signal at 54 from the microprocessor 18, the microprocessor 18
not being
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seen in FIG. 2. When signal 54 is driven above 0.7 volts, the transistor 36
turns on
and current flows from the batteries 46 and 48 through the inductances 38 and
40, via
the transistor 36 and through the resistor 44, thus completing the circuitry
to ground.
The voltage at 56 therefore rises and is monitored by amplifier 58 with the
gain of the
amplifier 58 being set by resistors 60 and 62 so as to produce a maximum
output, the
output being approximately 4 volts, when no current is flowing. As the voltage
at 56
rises, the voltage on a signal at 64 falls. At a certain point, as defined by
the gain of
the amplifier 58, the voltage at 66 set by a resistor divider formed by
resistors 68 and
70 (the resistor divider being identified at 72), with that certain point
being further
defined by the threshold of the Schmitt trigger interrupt input (not shown) of
a
microprocessor, the certain point being connected to the signal at 64, the
microprocessor being interrupted. The microprocessor then turns off the
transistor 36
for a predetermined "offtime" by setting the signal at 54 to ground allowing
energy
stored in the inductances 38 and 40 to be released via the diode 42 into
capacitor 74
and, via diodes 78 and 80, into capacitor 76. The microprocessor then turns
the
transistor 36 back on again, repeating the energy transfer cycle.
[0037] Operation of the present system as described hereinabove has advantages
over prior art systems employing a simple oscillator in that the peak current
through
the inductances 38 and 40 is a fixed value regardless of the value of the
inductor or
load, the only significant variation being caused by the tolerances of the
resistors 44,
68 and 70 and a five volt power supply voltage which is regulated, the voltage
being
indicated at 82. Total variation is therefore around ten percent. By
regulating the peak
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current, the maximum lamp current is regulated and a more consistent light
output is
maintained.
[0038] Using the signal at 54, the microprocessor can therefore determine
whether
to operate an inverter, that is, the boost converter circuit 20 as required by
software
operating the microprocessor. Further, the microprocessor determines a desired
"OFF
time". By varying the OFF time of the inverter, average lamp brightness can be
controlled to best advantage in the operation of differing lamps and in view
of
differing local regulations or differing product variations where lamp
brightness can
be traded for battery life depending upon relative importance in a given
installation.
In the present system, the "OFF time" and the variation of "OFF time" during a
battery discharge are set by parameters recorded on a product-by-product basis
in the
memory chip (not shown) of the EEPROM 32 during factory calibration. A
software-
controlled battery discharge profile can thus be set as necessary, such
variation in
product capability being achieved essentially at no cost.
[0039] Microprocessor control of the inverter involves use of the two
inductances
38 and 40 rather than a single inductor as is common in the prior art. In the
present
system, the inverter also powers the microprocessor and its support circuitry
when in
emergency mode. The two inductances 38 and 40 form a "split inductor" which
allows a lower voltage to be provided to the input of regulator 84 than the
voltage
which is provided to the lamp 50. As can also be appreciated, the regulator 84
acts to
generate the precise five volts required by the microprocessor. Accordingly,
addition
of two low cost components, that is, the inductance 38 and the diode 78,
results in an
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increase of up to ten percent in overall power conversion efficiency when the
inverter
is operating, thereby allowing a greater proportion of battery energy to be
provided to
the lamp 50 to meet lamp brightness requirements as necessary.
[0040] Once the inverter of the system ceases to operate as determined by the
software of the microprocessor , no power is supplied to the microprocessor or
its
associated support chips (not shown in FIG. 2). The diode 80, which comprises
a
Zener diode, blocks the current path from the batteries 46 and 48 via the
inductance
38 to the regulator 84 which is the five volt regulator. If a voltage of less
than 3.3
volts exists across the Zener diode 80, no current flows. Since the batteries
46 and 48
have a nominal voltage of 1.2 volts each and a realized maximum terminal
voltage of
approximately 1.4 volts, the Zener diode 80 will never conduct unless the
inverter is
operating. If the microprocessor is not powered, then the microprocessor does
not
provide the signals at 54 and at 88 and total power consumption is essentially
zero.
[0041] Accordingly, no need exists to isolate the terminals of the batteries
46 and
48 during shipping to prevent complete discharge or damage caused by a battery
polarity reversal, conditions which can develop with two series cells when one
cell
becomes completely discharged. Prior art lighting systems require battery
isolation by
disconnection or addition of a temporary insulator. Control of the inverter
through the
microprocessor further reduces cost and reduces the possibility of an
installation
mistake such as by forgetting to remove an insulator (not shown) from an
isolation
position relative to the batteries 46 and 48.
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[00421 Advantages derived through use of the EEPROM 32 have previously been
alluded to. In addition to maintaining a basic timing cycle, the EEPROM 32
provides
additional advantages which include elimination of the use of potentiometers
and the
manual process of setting such potentiometers in a factory environment.
Emergency
systems require accurate calibration to ensure that charge voltages and
currents are
correct, that the system goes into emergency mode at the required mains
voltage (80%
of nominal) and begins charging at the required voltage (85% of nominal).
Calibration software can further be provided to the microprocessor 18, the
calibration
software interacting with software in automated factory test equipment to
store
required thresholds in the EEPROM 32. Storage in the EEPROM 32 of
configuration
parameters allows control of system operation and system features. In addition
to the
features described above relative to the configuration of "OFF time", certain
features
are made available only on certain products and it is desirable to be able to
easily
change the features at the time of manufacture without using differing
versions of
software running in the microprocessor. This ability is particularly desirable
when the
microprocessor is "masked" with predefined code during manufacture. The system
configured according to the present invention contains 52 bytes of
configuration
information which the microprocessor software uses to control operation. The
invention uses 40 bytes of EEPROM storage to count events such as the number
of
brownouts and specified tests for later evaluation should a product be
returned from
the field. Precise evaluation is thus allowed of the performance of the system
under
actual conditions and allows improvement using such knowledge.
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[0043] Prior art self-test/self-diagnostic systems typically use a relay to
connect an
emergency lamp to a battery when power fails and/or to disconnect input power
to a
charger during diagnostic cycles to check transfer switch operation. Due to
the fact
that relays are typically expensive, it is therefore desirable to eliminate
the use of
relays in the first embodiment of the invention if at all possible due in part
to use of
NiCd batteries as the batteries 46 and 48. Further according to the present
invention,
and specifically the first embodiment thereof, a number of diodes are used to
separate
the power to various circuit elements, thereby eliminating the need for a
relay. The
basic circuit topology of the system is similar to the non-diagnostic
emergency system
described in the aforesaid patent. In this basic circuitry, an input of 277
volts or 120
volts to either capacitor 90 or capacitor 92 respectively reduces the AC mains
voltage,
a bridge rectifier 94 converting the mains voltage from AC to DC, the DC
current
passing through light emitting diodes 52 of the lamp 50 through current
measurement
resistor 96 and the batteries 46 and 48 before returning to the rectifier 94.
It should be
understood that a string of the light emitting diodes 52 can be taken to be
any
desirable number and not be limited to the four light emitting diodes shown in
FIG. 2.
[0044] The boost converter 24 described previously herein includes the diode
42 in
its topology and, by adding diode 98 to the path from the normal power supply,
normal power and emergency power can be combined to drive the same lamping,
that
is, the lamp 50. Power for the electronics of the microprocessor 18 is also
derived
from the normal power supply via diode 100 and is combined with the output of
the
inverter, that is, the emergency power, via the diode 78. Accordingly, both
the lamp
18
CA 02578890 2007-02-15
50 and microprocessor electronics are effectively powered by either source
without
the need for a relay. Additionally, microprocessor signal 102 is used to drive
a
transistor 104 to shunt the AC power source to allow software to perform
diagnostic
tests. By using the series battery/light emitting diode lamp technology of the
aforesaid
patent, the total power available from the AC power source can be kept small
with
easy bypass being possible through use of the small low cost Darlington
transistor
104 shown in the circuit. Zener diode 106 is disposed across the transistor
104 for
transient voltage protection.
[00451 FIG. 3 is a block diagram showing the relationship of FIGS. 3A, 3B and
3C, which FIGS. 3A, 3B and 3C illustrate in combination certain circuitry
utilized in
a first embodiment of the invention, the space available on a sheet of
drawings being
insufficient to allow said circuit to be reproduced on a single sheet.
Reference to FIG.
3 herein constitutes a reference to the circuitry shown in the combined
illustrations of
FIGS. 3A, 3B and 3C. As is seen in FIG. 3, a ten-pin connector 108 can be
employed
for providing all essential signals and power from the microprocessor 18 to
one or
more optional circuit boards such as seen in FIG. 4 to provide optional
features. As is
indicated at 30 in FIG. 1 and in relation to FIG. 3, the connector 108
connects to reset
circuitry 120 to provide unregulated DC power for subsystems shown on options
board 122 which regulate their own five volt or higher power supplies. The
connector
108 further provides a reset signal, regulated five volts for circuits which
require five
volts, battery voltage for allowing other circuits to monitor battery voltage,
a buzzer
output seen in FIG. 4 for systems requiring audible alarms and a one-wire
serial data
connection to a low power radio receiver (not shown) thus allowing remote
control
19
CA 02578890 2012-02-14
devices to be used to trigger self-test or other modes. Various daughter
boards
providing options can be plugged into the converter 108. Still further, a pair
of wires
carrying industry standard Lsup.2 C data signals from the EEPROM 32 and the
microprocessor 18 allow intelligent subsystems to communicate with the self-
diagnostic microprocessor. Full charging of a rechargeable battery results in
dissipation as heat all the energy taking the form of electric current flowing
through
the battery cell. Increasing the temperature of a battery cell reduces cell
life.
Microprocessor control of a shunt battery regulator configured as shown herein
in
FIG. 2 has as its purpose the reduction in charge current to the minimum
required to
overcome the effects of self-discharge once the battery is to be charged. The
circuitry
shown in FIG. 2 is similar to the shunt regulated battery charging system of
U.S. Pat.
No. 5,646,502. The system of the patent is essentially identical in most
respects to the
circuitry of FIG. 2 with the exception that the microprocessor 18 controls the
process.
[00461 Referring again to FIG. 2, it is to be understood that a percentage of
the
battery charge current through the lamp light emitting diodes 52 via the
resistor 96
will flow through the resistor 110 and the transistor 112 when the
microprocessor
generates a positive voltage above 0.7 volts at signal 114. A circuit is thus
provided
which allows the microprocessor to reduce the charge current once the
batteries 46
and 48 have been charged for a given time or have reached a given voltage as
measured at 116. Battery life can be extended substantially by providing such
circuitry.
CA 02578890 2007-02-15
[0047] The invention is further understood by reference again to FIG. 3, which
includes the circuitry of FIG. 2 therein. As noted above, FIG. 2 essentially
illustrates a
mains input power circuit section, a boost converter essentially comprising
the
inverter 20 and lamp and battery configurations. The entire circuitry of FIG.
2 is
incorporated into the circuit of FIG. 3. As has been indicated previously, the
reset
circuitry 120 effectively looks at a five volt line and remains inactive
unless a drop
occurs on the five volt line. If a drop occurs, the reset circuitry 120
outputs a low
pulse which resets the microprocessor 18, the microprocessor 18 being brought
back
to a given point in the program controlling the self-diagnostic function.
Transistors
124 and 126 function with Zener diode 128 inter alia to provide the reset
function
within the circuitry 120, manual reset at 130 also being provided.
[0048] As carryover from the description of the circuitry of FIG. 2, it is to
be
understood that the transistor 104 is utilized to simulate power outages
through
turning said transistor on. The transistor 36 essentially comprises the heart
of the
boost converter 20.
[0049] Continuing on with the circuitry of FIG. 3, capacitor 132 is seen to
function
as a filter capacitor and to provide DC offset at 134, the resistors
comprising the DC
offset 134 dividing the network to monitor the power line. Operational
amplifier 136
effectively detects the level of AC line voltage and connects to DC level by
comparison to a reference voltage. At 138, DC level is one/infinity to AC
input.
Integrator 140 comprised of capacitor 142, resistor 144 and diode 146 is
disposed
between the operational amplifier 136 and the microprocessor 18 in order to
provide
21
CA 02578890 2007-02-15
appropriate function. Pull up resistors 148 and 150 are provided between
EEPROM
32 and the microprocessor 18. DC level filtering is provided at 152 by
capacitors 154,
156 and resistor 158, 160. One of the capacitors looking at battery voltage
while the
other looks at load current to provide a leveling filter function. In essence,
the
operational amplifier 136 comprises the heart of a difference amplifier 137.
The
output of the difference amplifier 137 is DC level which is inversely
proportional to
AC output.
[00501 The EEPROM 32 essentially comprises a memory device having a non-
volatile program which stores configuration variables used to make decisions.
Log
variables are also stored by the EEPROM 32 to provide a record of failures and
the
like. Even if power is discontinued to the EEPROM 32, information is kept even
in
the absence of battery power or AC mains power. Capacitors 162 and 164
essentially
comprise decoupling capacitors which suppress noise. The serial connection
between
the EEPROM 32 and the microprocessor 18 allows expansion of functionality with
other plug-in modules.
100511 Remaining portions of the circuitry of FIG. 3 including a crystal clock
166
comprising a two megahertz resonator providing clocking for microprocessor
frequency standards. Timing functions for the analog to digital converter in
microprocessor 18 are provided by capacitor 168. Switch 170 is provided for
test
purposes particularly for testing, rescheduling tests or cancelling tests.
Capacitors 172
and 174 stabilize the five volt power supply and bypass high frequencies.
Diode
22
CA 02578890 2007-02-15
arrangement 176 provides bicolor light emitting diodes functioning with
resistor 178
as an indicator circuit.
[0052] In essence, the microprocessor 18 comprises integrated circuitry having
various control functions. In particular, if the microprocessor 18 detects
loss of
power, data is stored to the EEPROM 32 in order to save operational history.
[0053] Considering now the second embodiment of the invention as is
particularly
shown in FIG. 5, it is to be noted that the differences between the circuitry
of FIG. 5
and FIG. 3 are related as has been described hereinabove to basic load and
battery
chemistry considerations as exist between emergency exit signage utilizing
light
emitting diodes, requiring the circuitry of FIG. 3, and emergency unit
equipment
utilizing incandescent lamping, requiring the circuitry of FIG. 5. In the
circuitry of
FIG. 3, nickel/cadmium batteries are utilized as the emergency power source
while
lead-acid batteries are utilized with the circuitry of FIG. 5.
[0054] Much of the circuitry of FIG. 3 is incorporated into the circuitry of
FIG. 5,
particularly the microprocessor 18 and the EEPROM 32. Further, reset circuitry
120
is essentially identical as are the crystal clock 106 and the connector 108.
D.C. local
filtering at 152 is produced in a similar fashion and the pull-up resistors
operate in a
similar manner. The difference amplification function centering on the
operational
amplifier 136 and associated circuitry is also provided in the same manner as
is the
D.C. offset function at 134. Other similarities exist between the circuits of
FIG. 3 and
FIG. 5.
23
CA 02578890 2007-02-15
[00551 The following description of FIG. 5 is based in part upon differences
between the self-diagnostic circuits of FIG. 3 and FIG. 5 respectively.
[00561 It is to be understood that FIG. 5 is a block diagram showing the
relationship of FIGS. 5A, 5B and 5C, which FIGS. 5A, 5B and 5C illustrate in
combination certain circuitry utilized in a second embodiment of the
invention, the
space available on a sheet of drawings being insufficient to allow said
circuitry to be
reproduced on a single sheet. Reference to FIG. 5 herein constitutes a
reference to the
circuitry shown in the combined illustrations of FIGS. 5A, 5B and 5C. For
those
portions of the circuitry of FIG. 5 which differ from the circuitry of FIG. 3,
a more
detailed discussion will be provided hereinafter.
[00571 The D.C. input capacitors 90 and 92 of FIGS. 2 and 3 comprise an
impedance divider network responsible for reducing input voltage and limiting
input
current to the circuitry of FIG. 3. In FIG. 5, a step-down transformer 200 is
employed
to produce this function. The transformer 200 combines with bridge rectifier
diodes
202, 204, 206 and 208 and voltage regulator 210 to comprise the main current
carrying elements of the charger circuitry of FIG. 5. Transistor 212 controls
the
voltage regulator 210 which is used as a pass element for the charge current
in the
circuitry of FIG. 5. The microprocessor 18 of FIG. 5 provides a control signal
from
pin 9 to turn charge current on and off to battery 216 via the transistor 212
and the
voltage regulator 210. The software program contained in the microprocessor 18
determines whether this "switch" is on or off. In essence, the software
program in the
microprocessor 18 is responsible for regulating charge voltage, via pin 9, to
a
24
CA 02578890 2007-02-15
temperature-compensated voltage level, based on charge current and battery
voltage
that the microprocessor 18 is monitoring, via pins 2 and 3, of the
microprocessor 18.
[0058] Software control in the circuits of the invention for implementation of
charger control is advantageous relative to chargers utilizing hardware for
control of
voltage regulation set points and temperature compensation adjustment factors.
In
particular, these advantages include the fact that software control-allows a
system to
take advantage of the monitoring of battery voltage and current inherent in
the self-
diagnostic system and utilizes this function for the dual purpose of charge
control.
Further, such a system is easily configurable to different battery voltage
levels and
battery chemistries by simply changing configuration variables used by the
software
program contained in the memory of the EEPROM 32, these configuration
variables
containing charge voltage level setpoints and temperature compensation
factors. Still
further, the microprocessor 18 can make use of an internal temperature sensing
diode
to provide a low cost method of measuring the temperature inside of the unit
so that
the charger output voltage can be temperature compensated for ambient
temperature
to maximize battery life at temperature extremes.
[0059] Referring back to FIG. 5 in particular, a lamp output section of the
circuitry
of FIG. 5 consists of a simple relay transfer circuit comprising resistor 218,
transistor
220, diode 222 and relay 224. This relay transfer circuit essentially replaces
the
inverter and peak current detection components of the circuitry of FIG. 3. Pin
8 of the
microprocessor 18 is used to turn on and off the relay 224 via the transistor
220 when
microprocessor software detects AC power failure or for scheduled self-
diagnostics
CA 02578890 2007-02-15
testing. Since the incandescent lamping 226 of FIG. 5 provides a larger DC
load in
the emergency mode, it is necessary to utilize the relay transfer circuit
shown in FIG.
5.
[0060] In the circuitry of FIG. 3, a simple current sensing element is
provided in
the form of the resistor 96. In the circuitry of FIG. 5, a current sensing
circuit is seen
to be provided by processor 18, amplifier 230, resistors 232, 234, 236, 238,
240 and
258; capacitors 242, 246, 248 and 250; and diodes 252, 254 and 256. A voltage
converter circuit is provided by the voltage converter integrated circuit 228
and the
capacitors 246, 248 and 250 and diode 256, this voltage converter circuitry
228
providing a -5V rail for the amplifier circuit which is formed around the
amplifier
230. The amplifier circuit formed around the operational amplifier 230 is a
variation
of an active non-saturating, full-wave precision rectifier circuit such as is
referred to
as an absolute value circuit. The left-hand portion of the circuit is an
active-wave
rectifier circuit while the right-hand portion of the circuit is an inverting
summing
amplifier.
[0061] In operation, the circuitry of FIG. 5 should first be considered to be
in the
emergency mode. In this state, the coil of the relay 224 is energized to
provide a path
for battery current to flow to ground through the lamping 226 which comprise
DC
lamps. This lamp current by design must flow back into the negative terminal
of the
battery 216 through sense resistor 258, thereby creating a negative voltage
potential
with respect to ground at vin. With vin as a negative input voltage, the
output va of
the left-hand rectifier circuit is va=0. Accordingly, one input to the summing
circuit
26
CA 02578890 2007-02-15
has a value of zero. However, vin is also applied as an input to the summing
circuit.
The gain for this input is set up by the resistors 236 and 238 and is equal to
-5 using
the well-know equation for inverting amplifiers -Rf/Ri. Since vin is negative
and the
gain of the circuit is also negative, the output vO=-5-vin and will be
positive for this
condition.
[00621 When emergency unit equipment utilizing the circuitry of FIG. 5 is
powered by alternating current and is charging the battery 216, charge current
flows
through the battery 216 and the sense resistor 258 to ground, thus creating a
positive
voltage at vin. In this condition, the output of the left-hand rectifier
portion of the
circuit va=-vin. The voltage va appears as one input to the summing circuit,
and the
gain for that input is -15. As before, vin also appears directly as an input
to the
summing circuit. The net output is then vO=-5vin-15va=-5vin-15(-vin)=10vin.
The
output of the circuit is therefore positive with a gain of 10 which provides
more
amplification of the smaller input voltages which will occur once the battery
216 is
charged and the current flow is reduced to a trickle charge.
[00631 The circuitry thus described provides a number of benefits for
accomplishment of the self-diagnostic function. In particular, the
microprocessor 18
has the ability to calibrate itself to the output of the circuitry during the
manufacturing
process, thereby avoiding the use of high tolerance components or trim pots
while still
maintaining an accurate measurement of current magnitude. Further, the
transformation of both negative and positive input voltages to positive output
voltages
meets the requirement of the microprocessor Analog to Digital (A/D) input
27
CA 02578890 2007-02-15
requirements for a positive input voltage less than a 3.5V dc. The present
circuit also
provides the ability to provide a higher gain for smaller voltage drops across
the sense
resistor 258 when the unit is charging to allow the circuitry to more
accurately
measure charge current. The ability of the present circuit to provide lower
gain when
operating in the emergency mode and when the voltage drop across the sense
resistor
258 is therefore greater, allows the circuitry to measure the larger currents
which flow
when the lamping 26 is on without exceeding maximum input voltage on the A/D
input of the microprocessor 18. While specific gain values are listed herein,
these gain
values can change with wattage.
[0064] The foregoing description of the exemplary embodiments of the invention
has been presented only for the purposes of illustration and description and
is not
intended to be exhaustive or to limit the invention to the precise forms
disclosed.
Many modifications and variations are possible in light of the above teaching.
The
embodiments were chosen and described in order to explain the principles of
the
invention and their practical application so as to enable others skilled in
the art to
utilize the invention and various embodiments and with various modifications
as are
suited to the particular use contemplated. Alternative embodiments will become
apparent to those skilled in the art to which the present invention pertains
without
departing from its spirit and scope.
28
