Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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MECHANISM FOR ~~fIRELESS MODEM POWER CONTROL
BACKGROUND OF THE INVENTION:
Field of the lnvention:
[0001 ] The present invention generally relates to power control for a
computer
peripheral device, and more particularly to a mechanism that simulates the
insertion and removal of a PCMCIA card in order to control power to the card.
Status of the Prior Art
[0002] PCMCIA (Personal Computer Memory Card International Association)
cards are peripheral devices that are inserted into a dedicated slot or port
on
computer devices. The PCMCIA card may be a wireless device such as a modem
or LAN card. The PCMC1A standard includes specifications that require
conformity to features for PCMCIA developers.
[0003] The physical requirements defined by the PCMCIA specification may
define the number of pins in the connector (i.e., sixy-eight), the pin
assignments,
IS the size of the card, the power requirements of the card, etc.... The
standards
ensure that peripheral cards meeting the requirements will function in
different
devices. For instance, a card confirming to a Type 1 PCMC1A specification may
function in a notebook computer, a PDA, a digital camera, or any other
electronic
device equipped with a PCMCIA slot.
[0004) The software requirements ensure that the PCMCIA card will be
operative on the different devices that the card is plugged into. For example,
card
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services provide an interface software requirement that handles communications
between the PCMCIA card and the computer. The primary purpose of the card
services is to inform the computer about the card including the amount of
memory
in the card and the type of data. On the other hand, socket services identify
when
the card is in the slot of the computer and provide a method for the computer
to
access the slot and card. Socket services check each PCMCIA slot of the
computer to determine whether a card is inserted therein.
[0005) Typically, when a user inserts a PCMCIA card into the dedicated slot of
an electronic device, the electronic device detects the presence of a card via
the
socket service with dedicated pins of the slot. If the card is detected, then
the host
device will provide power. to the card. The socket service is enabled such
that the
PCMCIA card may be plug-and-play and hot swappable if needed. The PCMCIA
specification is designed such that power is always applied to the card when
card is
in the socket. Upon insertion of the card into the PCMCIA socket, the card
will
be powered up. It is possible through the operating software of the electronic
device to power down the PCMCIA card into a sleep mode. In the sleep mode,
the card is minimally powered in order to save energy consumption. However,
total cessation of .power is not possible because some circuitry of the card
must
remain on in order to determine when to exit the sleep mode.
[0006] Often times, it is desirable to completely power down the PCMCIA card.
For instance, if the card is a wireless device such as a CDPD wireless modem,
the
modem must be turned off during use on an aircraft in order to avoid
interference.
Additionally, if the card is used in a small portable device such as a PDA,
then the
modem should be completely powered down in order to conserve battery power
when not in use. In the PCMC1A standard, the only way to ensure that the card
is
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completely powered down (i.e., turned off) is to remove the card from the host
electronic device or turn it off via a card. service utility which is
complicated for
normal users and software (OS) dependent. Furthermore, you can only turn the
card off, not turn it on. You have to remove the card from the socket and
insert it
back in to turn on the power.
(0007] Removing the card from the host electronic device can be inconvenient.
Often times, the user of the card does not realize that the device must be
removed
to completely turn the device off. Once removed, the user must find a place to
safely store the card. PCMCIA cards are fragile electronic devices which must
be
properly stored when not used in the host device in order to protect the card.
Accordingly, it can be inconvenient for the user to remove the card in order
to
completely power down the card.
[0008] The present invention addresses the above-mentioned deficiencies in the
power control of PCMC1A cards by providing a mechanism which provides zero
power usage for the PCMC1A card. The present invention allows the card to
remain in the. host device while still completely powering down the card:
Additionally, the mechanism of the present invention allows the card to be
turned
off and on by the user with very little effort. In fact, the mechanism of the
present
invention allows the user to control power to the card via a natural action.
SUMMARY OF THE INVENT10N
[0009] In accordance with the present invention, there is provided a mechanism
for providing zero power control of a peripheral device such as a PCMCIA card
that is insertable into a host device. The mechanism comprises a switch
electrically connected to two card detecting pins of the host device. The
switch is
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operated by a retractable antenna of the card. In this respect, when the
antenna is
in a retracted position, the switch generates an appropriate "removed" signal
to the
card detecting pins. The "removed" signal simulates removal of the PCMCIA
card from the host device such that the operating software of the host device
will
S not supply power to the card. In reality, however, the card has not been
removed
from the host device. On the other hand, when the antenna is in the extended
state, the switch will generate an "inserted" signal to the card detecting
pin. The
"inserted" signal informs the host device operating system that the card is
inserted
and that power should be applied to the card. In this regard, the operating
system
of the host device functions as if the card has been inserted imo the PCMCIA
slot.
[0010] The switch may be a mechanical switch which senses the position of the
antenna. Accordingly, when the antenna is in the retracted position (i.e.,
inserted
within the card), the switch will be positioned to generate the "removed"
signal.
Conversely, when the antenna is moved to the retracted position, the switch
will be
positioned to generate the "inserted" signal.
[0011] The PCMCIA specification requires two pins for the card and the host
device for detecting the presence of the PCMCIA card. When the pins are driven
to a ground potential by the insertion of the card, then the operating system
of the
host system knows that a card has been inserted. In the preferred embodiment
of
the present invention, when the antenna is in the extended position, the
switch
connects the detecting pins to a ground potential thereby simulating the
insertion of
the card. On the other hand, when the antenna is in the retracted position,
the
switch removes the ground potential from the detecting pins thereby simulating
removal of the card eventhough the card has not been removed. Upon sensing the
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simulated.removal of the card, the operating system of the host device will
turn pff
power to the card.
[0012] It will be recognized that the switch may be a mechanical micro switch
or
any other type of non-electrical switchlrelay which connects the card
detection pins
to ground. The operating system is fooled into thinking that the card has
either
been inserted or removed depending on the position of the switch.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] These as well as other features of the present invention will become
more
apparent upon reference to the drawings wherein:
Figure 1 is a block-level diagram of a power control constructed
in accordance with the present invention in the "off" state; and
Figure 2 is a block-level diagram of the power control shown in
Figure 1 in the "on" state.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0014] Referring now to the drawings wherein the showings are for purposes of
illustrating a preferred embodiment of the present invention only, and not for
purposes of limiting the same, Figure 1 illustrates a power control
constructed in
accordance with the present invention for a PCMCIA card 10 that is inserted
into a
PCMClA slot 12 of a host computer or electronic device. The PCMCIA slot 12
may be a port or other type of connecting device conforming to the PCMCIA
specification. The slot 12 is housed within the host computer and is adaptable
to
receive the PCMCIA card 10. The slot 12 has two detecting pins CDl and CD2
which detect the presence of the card 10. Adore particularly, when the card 10
is
inserted into the slot 12, the detecting pins CD1 and CD2 are driven low
(i.e.,
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ground) by the card. The host device detects the pins being driven low and
applies
power to a V + pin of the slot 12. . When the card 10 is removed, the
detecting
pins CD1 and ~ CD2 are driven high and power is removed from the V + pin.
Typically, the operating system of the host device determines the status of
the
detecting pins CDl and CD2 and controls the power to V + .
[0015] The power control of the present device includes a switch 14 connected
to the CD1 and CD2 pins of the card 10. The switch 14 has a first lead 36
connected to the CDl and CD2 pins, and a second lead 18 connected to a ground
potential, as seen in Figures 1 and 2. The first lead 16 is connected to a
lever 20
l0 of the switch 14 that is normally biased in a closed position by a spring
(not
shown). In the normally closed position, the lever 20 will contact the second
lead
18, as seen in Figure 2. When contacting the second lead 18, the lever 20 will
electrically connect the first lead 16 with the second lead 18 thereby
electrically
connecting pins CD1 and CD2 to the ground potential. As such, when the switch
14 is in the normally closed position, the switch 14 will drive the detecting
pins
CDl and CD2 to ground thereby simulating the insertion of the card 10 into the
slot 12. However, when the switch 14 is in the open position, the detecting
pins
CD 1 and connected only to the first lead 16 will not be driven to ground
thereby
simulating the removal of the card 10. Accordingly, it is possible to simulate
the
insertion and removal of card 10 in the slot 12 by opening and closing the
switch
14.
[0016] In the preferred embodiment of the present invention, the switch 14 is
positioned in a location whereat the movement of a retractable antenna 22 will
open and close the switch 14. More specifically, the antenna 22 will slide
within
the card 10 from a retracted position (shown in Figure l ) to an extended
position
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(shown in Figure 2). The antenna 22 slides within the card ID on a track or
other
suitable enclosure. The antenna 22 is in the retracted position when the
antenna 22
will not substantially protrude from the card 10. In the extended position, as
seen
in Figure 2, a majority of the antenna 22 protrudes from the card 10. It will
be
recognized that in the extended position, the antenna 22 will be able to
transmit
and receive signals better than in the retracted position due to less
interference
from the host device into which the card 10 is inserted.
[0017] The extension and retraction of the antenna 22 controls the power to
the
card 10. More specifically, the switch 14 is placed within the card 10 such
that
when the antenna 22 is in the retracted position, an interior end 24 displaces
the
lever 20 to the open position, as seen in Figure 1. The interior end 24
contacts the
lever 20 such that an open circuit is created between the detecting pins CD 1
, CD2
and ground thereby simulating the removal of the card 10. V1'hen the antenna
22 is
moved to the extended position, as shown in Figure 2, the lever 20 closes and
drives the detecting pins CDI and CD2 to the ground potential. As previously
mentioned, the switch 14 closes to the normally closed position due to the
biasing
action of the spring (not shown). When the switch 14 .is in the closed
position, the
detecting pins CDl and CD2 are driven to the ground potential thereby
simulating the insertion of the card 10.
[0018] By opening and closing the switch 14, it is possible to simulate the
insertion and removal of the card 10 without physically removing the same. In
this sense, the switch 14 generates a "removed" signal to the detecting pins
CD1
and CD2 when the antenna 22 is retracted and the switch 14 is in the open
position. Conversely, when the antenna 22 is in the extended position and the
switch 14 is closed, an "inserted" signal is generated by the switch 14 to the
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detecting pins CD1 and CD2. Accordingly, it is possible to simulate the
insertion
and removal of the card i0 within the slot 12 through the movement of the
antenna
22. It will be recognized that moving the antenna 22 is a natural act for a
user
wishing to use the card 10 such that the card 10 can be easily powered on and
off.
[0019] The switch 14 has been described as being a mechanical micro switch
which is activated from movement of the antenna 22 via the lever 20. However,
it
will be recognized that the switch 14 may be a non-electrical switchlrelay
which
connects the, card detection pins CD1 and CD2 to ground. Any device which
detects the position of the antenna 22 rnay be used to drive the detecting
pins CDl
and CD2 to the proper voltage. For instance, an optical sensor may be used to
determine the position of the antenna 22 within the card 10. The optical
sensor
will open and close the switch 14, as necessary. On the other hand, a magnetic
device may be used to determine the position of the antenna 22.
[0020] Additional modifications and improvements of the present invention may
also be apparent to those of ordinary shill in the art such as adapting the
power
control for different card standards. For instance, even though the present
invention has been described for PCMCIA cards, it will be recognized that the
power control for other formats of cards may utilize the present invention.
Thus,
the particular combination of parts described and illustrated herein is
intended to
represent only a certain embodiment of the present invention, and is not
intended
to serve as a limitation of alternative devices within the spirit and scope of
the
invention.
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