U.S. patent application number 10/132364 was filed with the patent office on 2003-10-30 for battery disable/enable control circuitry of a portable computing device.
Invention is credited to Briggs, Scott W., Edwards, Michael W..
Application Number | 20030201755 10/132364 |
Document ID | / |
Family ID | 29248743 |
Filed Date | 2003-10-30 |
United States Patent
Application |
20030201755 |
Kind Code |
A1 |
Briggs, Scott W. ; et
al. |
October 30, 2003 |
Battery disable/enable control circuitry of a portable computing
device
Abstract
A portable computing device includes at least three buttons and
circuitry for sensing the pressing of at least three buttons, one
being recessed, and in response to such sensing provides a battery
disable signal to a non-removable battery. The portable computing
device further includes circuitry for sensing the coupling of the
device to a device cradle, and in response to such coupling, or in
response to the press of the recess button, provides a battery
enable signal to the non-removable battery.
Inventors: |
Briggs, Scott W.; (Cypress,
TX) ; Edwards, Michael W.; (Houston, TX) |
Correspondence
Address: |
AKIN, GUMP, STRAUSS, HAUER & FELD
711 LOUISIANA STREET
SUITE 1900 SOUTH
HOUSTON
TX
77002
US
|
Family ID: |
29248743 |
Appl. No.: |
10/132364 |
Filed: |
April 25, 2002 |
Current U.S.
Class: |
320/135 |
Current CPC
Class: |
G06F 1/24 20130101; H02J
7/0029 20130101; G06F 1/1635 20130101; G06F 1/1632 20130101; G06F
1/26 20130101; G06F 1/1626 20130101 |
Class at
Publication: |
320/135 |
International
Class: |
H02J 007/00 |
Claims
We claim:
1. A portable computing device, comprised of: at least three
buttons wherein at least one button is recessed; and battery
disable control circuitry to generate a battery disable signal in
response to sensing communications from at least three of the
buttons.
2. The portable computing device of claim 1, wherein at least two
buttons are application buttons.
3. The portable computing device of claim 2, wherein the
application buttons are non-adjacent.
4. The portable computing device of claim 1, the device further
comprising: a right side; and a left side; wherein one of the
buttons is near the right side and another of the buttons is near
the left side.
5. The portable computing device of claim 1, wherein at least one
button is a reset button.
6. The portable computing device of claim 1, wherein the battery
disable signal is generated after sensing communication from at
least three of the buttons for a predetermined duration.
7. A portable computing device, comprised of: a button; and battery
enable control circuitry to generate a battery enable signal in
response to the sensing of a communication from the button when the
device is connected to a device cradle.
8. The portable computing device of claim 7, wherein the button is
a recessed button.
9. The portable computing device of claim 7, wherein the button is
a reset button.
10. A method of disable generation for a battery of a portable
computing device, the device comprising at least three buttons, the
method comprising the steps of: sensing button communications from
at least three of the buttons wherein at least one button is
recessed; and generating a battery disable signal to disable the
non-removable battery in response to the sensing step.
11. The method of claim 10, wherein at least one button is the
reset button.
12. The method of claim 10, wherein at least two buttons are
application buttons.
13. The method of claim 12, wherein the two application buttons are
non-adjacent.
14. The method of claim 10, wherein one of the buttons is near a
right side of the device and another of the buttons is near a left
side of the device.
15. The method of claim 10, wherein the battery disable signal is
generated after sensing the communications from at least three of
the buttons for a predetermined duration.
16. A method of enable generation for a battery of a portable
computing device, the device comprising a recessed button,
comprising the steps of: sensing a communication from the recessed
button; and generating a battery enable signal in response to the
sensing step.
17. The method of claim 16, wherein the recessed button is a reset
button.
18. A method of enable generation for a battery of a portable
computing device, comprising the steps of: detecting connection of
the device with a device cradle; and generating a battery enable
signal in response to the detecting step.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to control of enabling and disabling
battery connections of a portable computing device.
[0003] 2. Description of the Related Art
[0004] The advantages of portable computing devices continue to be
recognized in an ever growing variety of personal and work
activities. Being portable, these devices have many design features
and constraints not present in their desktop counterparts. For
example, such portable computing devices must rely on battery power
rather than on the traditional source of power, the electrical
outlet. This dependence on a battery source has introduced many new
design constraints including: battery charge capacity, battery size
requirements, battery under-voltage threats and battery operational
impact. Given these constraints, designers have attempted to
provide portable computing devices that best satisfy the consumer's
needs while balancing the demands inherent in the above identified
constraints.
[0005] The requirement that portable computing devices be able to
function without the tether of a cord plugged into a standard
electrical outlet requires that they operate on batteries. A unique
feature of portable computing devices, not present in many other
battery operated portable electrical devices, is a need for a
continuous supply of power even after being turned off. This power
demand is due to the operational nature of the volatile memory
commonly contained in these devices. Volatile memory requires
continuous power to retain the data stored therein. Because it is
common for portable computing devices to contain volatile memory,
it is important that such devices maintain a constant supply of
power.
[0006] This need for a continuous supply of power presents many
design challenges. For example, because batteries have a limited
storage capacity, and because this capacity can be depleted through
either operational use, or non-use (i.e., the volatile memory
problem), such batteries need to be eventually recharged or
replaced. In the case of replacement, when such batteries are
replaced there is a period, between the removal of the old battery
and insertion of the new battery, where no battery is connected to
the device, and as such, there is a period where the volatile
memory is without power. To prevent this period of non-power, one
solution has been used which incorporates two batteries: a main or
primary battery for supplying the normal operating power for the
device, and a back-up or secondary battery for use as fail-over
power. More specifically, during normal operations, whether turned
on or not, the device draws its power from the main battery. It is
only when the supply of power from this main battery is interrupted
that the back-up battery is drawn upon. This dual battery design
allows for the replacement of a main battery of a portable
computing device without losing power and thus not losing the data
stored in the volatile memory. Although this dual battery approach
solves the problem of replacing replaceable batteries, it does not
solve the problem discussed below relating to the general large
size of replaceable batteries.
[0007] Further, there continues to be a demand for batteries that
can supply continuous power for the longest amount of time before
recharging. Generally, and especially among batteries of similar
components, the larger the battery, the longer it can hold a
charge. Thus, size not being a factor, very large batteries could
be used to provide ever longer periods of charges. However, because
it is almost always advantageous to produce portable computing
devices that are as small as possible, and because the batteries
used in such devices directly impact the ultimate size of such
devices, the batteries need to be as small as possible, while
providing as much power as possible. Further, user replaceable
batteries must be designed with sufficient casing as to protect
anyone handling such batteries from its contents. This
encapsulation requirement means that such replaceable batteries are
inherently larger than their non-replaceable counterparts. Thus,
there is a tradeoff between using replaceable batteries with larger
size and non-replaceable batteries that are smaller. Because of
their smaller size, it is generally preferable to use
non-replaceable batteries in portable computing devices.
[0008] Another design constraint inherent in using batteries is
that batteries generally become damaged when their power is drawn
below a particular level of charge (under-voltage). Therefore, to
prevent permanent battery damage, it is important to prevent
batteries from having their charge drawn down to such levels. It is
not uncommon for circuitry to be included with portable computing
devices which acts to disconnect or disable its battery when the
battery charge level reaches a particular level. This is generally
not an action one wishes to allow to occur on such devices since
the disabling of the battery will cause the loss of data in the
device's volatile memory.
[0009] It is also important to deliver the newly purchased portable
computing device to the purchaser in the most user friendly
condition as possible. Part of this user friendly condition relates
to the batteries. For example, in the dual battery design discussed
above, the most user friendly condition would be with both
batteries installed and the system already powered up when the
shipping box is opened. However, such a level of "user
friendliness" is impractical and/or too costly as leaving the
system fully powered up upon preparation for shipping would result
in the batteries being fully discharged before reaching the
purchaser. And further, without any type of automatic disabling
circuitry, as discussed above, the batteries could suffer permanent
damage. An alternative might be to ship the device with both
batteries installed, but without leaving the system powered up.
This approach would not result in the batteries being discharged as
fast as the previous scenario, but would still likely result in the
battery being fully discharged before reaching the purchaser. In
practice, each of these two scenarios would result in very low user
friendly conditions as both would require the purchaser to both
diagnose the problem and replace or recharge the batteries before
being able to operate the device.
[0010] A more user friendly condition would be to ship the device
without any batteries installed. This would eliminate the need for
the user to both diagnose why the device would not operate and to
either recharge or replace the batteries. However, this would still
require the purchaser to install the batteries before operating the
device. Some manufacturers have devised a more user friendly way to
ship their dual battery computing devices where the devices are
shipped with the back-up battery already installed and requiring
the purchaser to only install the main battery (both replaceable
batteries). This is achieved by installing the back-up battery in
the device where an insulator is placed between this battery and
its electrical contact and where the purchaser is required to pull
the tab connected to the insulator to remove the insulator and to
allow for the electrical connection between the back-up battery and
the device contacts. Although this removes the need to install two
batteries, it still requires two actions by the purchaser before
the device is ready for use. The possibility also exists that the
tab might separate from the insulator leaving all or part of the
insulator between the back-up battery and the electrical contact.
Further, as discussed above, this design is less advantageous than
other designs using non-replaceable batteries since the device
would be required to be larger to accommodate the larger
replaceable batteries.
[0011] Another approach to the shipment of the portable computing
devices has been to ship the devices with the battery(s) installed,
where such devices have circuitry including a battery disabled and
battery enabled modes, and the device is shipped with the device in
the battery disabled mode. For example, such designs as the Compaq
iPAQ 3700 series have included the use of a single non-replaceable
battery with such disabled and enabled modes. As shown in FIG. 3,
such a unit 500 is shipped in the disabled mode and the purchaser
activates the unit, i.e., the user changes the unit from the
battery disabled mode to the battery enabled mode, by locating a
sliding door 522 on the bottom side 530 of the unit 500, and using
the accompanying stylus (not shown), sliding the door 522 open, and
flipping a slide switch 520 to the on position. Note that reset
button 514 is not used in this battery enable procedure. This
approach has its drawbacks as users might be confused as to how to
power up the system. The users might have a problem identifying the
door, or that the switch was behind that door. Another potential
negative aspect of this approach is that the door may potentially
develop a rattle over time.
[0012] Regardless of which of the above approaches involving
shipping the batteries in a disabled state is used to ship the
portable computing device, each has the common feature of an
activation scenario that cannot easily occur accidentally during
shipping. As explained above, one needs the batteries to be
installed, while another needs a plastic tab removed, and finally
another needs a switch behind a door to be thrown.
[0013] Designers have also chosen to include a disable battery
function in their portable computing devices. Designers have
provided different ways, either passive or active, for users to
place the units in a disabled state. The passive designs, where a
physical break between the battery and the device is required,
include those devices where removable batteries are used and the
only way to accomplish a disabled state is to remove the batteries.
For example, the Compaq Aero 1550 Pocket PC required the removal of
both a main battery and a back-up battery. Active designs, where
some form of button pressing or switching throwing is needed,
include devices such as the Compaq iPAQ 3700 series which simply
required the opening of the door at the bottom of the unit and
throwing the switch to the disabled position. Another unit was the
Hewlett Packard Jornada that required that the unit be turned off
using the power button, followed by the simultaneous pressing of
the reset button and the power button. The Casio E115 required the
simultaneous pressing of the power button and reset button for two
seconds which invokes a screen prompt, followed by the pressing of
a control button.
SUMMARY OF THE INVENTION
[0014] A portable computing device includes at least three buttons
and circuitry for sensing the pressing of at least three buttons,
one being recessed, and in response to such sensing provides a
battery disable signal to a non-removable battery. The portable
computing device further includes circuitry for sensing the
coupling of the device to a device cradle, and in response to such
coupling, or in response to the press of the recess button,
provides a battery enable signal to the non-removable battery.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] A better understanding of the present invention can be
obtained when the following detailed description of the disclosed
embodiment is considered in conjunction with the following
drawings, in which:
[0016] FIG. 1 is a component diagram showing the face of a portable
computing device including multiple buttons and a display, and in
phantom, the battery and circuitry located there behind;
[0017] FIG. 2 is a component diagram showing the bottom of the
portable computing device of FIG. 1 including a port and a rest
button, and in phantom, the battery and circuitry located there
behind;
[0018] FIG. 3 is a component diagram showing the bottom of a prior
art portable computing device including a dedicated switch for
controlling the enabling and disabling of the battery; and
[0019] FIGS. 4 is a circuit diagram showing exemplary battery
disable/enable control circuitry of the portable computing device
of FIG. 1 that interprets button activity into battery enable and
disable requests.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
[0020] FIGS. 1 and 2 illustrate an example of a portable computing
device 100 implemented according to the disclosed techniques. The
term "portable computing device" generally refers to a portable
device with a subset or superset of typical computing functions of
a personal computer. For purposes of explanation, specific
embodiments are set forth to provide a thorough understanding of
the present invention. However, it will be understood by one
skilled in the art, from reading the disclosure, that the invention
may be practiced without these details. Moreover, well-known
elements, devices, process steps, and the like, and including, but
not limited to, electronic circuitry components and connections,
are not set forth in detail in order to avoid obscuring the
disclosed system.
[0021] FIG. 1 illustrates an example of a portable computing device
100 with a front surface or face 200, left side surface 210, right
side surface 220, bottom surface 230 and a top surface 240. FIG. 1
also shows the front surface 200 of the device containing a display
screen 290 for text and graphics, application programming buttons
102, 104, 106 and 108, and navigation button 105. Specifically,
button 102, near the left side 210 of the device 100, is the
calendar button. In addition, button 102 is used in conjunction
with buttons 108 and 114 (FIG. 2) in performing a battery disable
function. Buttons 108 and 102 re non-adjacent. Button 104, slightly
further from the left side 210 of the device 100 than button 102,
and adjacent to button 102, is the contacts button. Button 108,
near the right side 220 of device 100, is the task button. As
mentioned above, button 108 is also used in a battery disable
function. Button 106, slightly further from the right side 220 of
the device 100, is the inbox button. Button 105, located centrally
between the left and right sides, 210 and 220, respectfully, is
used as the navigation and scroll through list button. Button 112
is the power button. On the portable computing device's left side
210, and as shown in FIG. 2, is button 110 which is the
record/application button. On the portable computing device's
bottom 230, a reset button 114 and a charging and communications
port 232 is provided. The device bottom 230 is provided without a
battery enable/disable switch or accompanying door. As described
above, button 114 is also used in the battery disable function. It
is contemplated that more or less buttons could be incorporated
into the device 100 and that the functionality of particular
buttons, or button combinations, could vary without departing from
the spirit or scope of the invention. Further, the buttons depicted
in the figures may be sensitive to pressure, light, magnetism or
other like properties. Also, the buttons may be virtual buttons
like those seen in touch screen type devices where either a contact
sensitive membrane covering the screen is used, or where a
coordinate mapping is used, such as where sensors along the sides
of the screen sense the location of an object in contact, or in
approximate contact, with the screen.
[0022] As shown in FIGS. 1 and 2, the portable computing device 100
includes a lithium ion flat cell battery 300, and circuitry 400 to
either enable or disable the battery connection to the device 100
depending on whether an enable or disable signal is generated
within the device 100. The flat cell battery 300 is neither
removable, nor does it having casing typically found with otherwise
replaceable batteries. For a battery protection circuit to disable
the battery connection to the portable computing device 100, the
circuit must receive a battery disable signal with a predetermined
duration such as two or more seconds. The battery protection
circuit includes a timer defining the particular duration.
Concerning the battery enable signal, it is contemplated that the
detection of the coupling between the device 100 and a device
cradle or dock could be performed by a number of mechanisms used to
sense such a coupling including, but not limited to, electrical,
mechanical, optical or magnetic detection mechanisms. It is also
contemplated that the coupling necessary to activate the battery
connection to the device 100 via a battery enable signal could be a
number of devices other than a device cradle or dock, such as a
communications device, an A/C power source, or simply a
dedicator/activator device used solely to perform such
activations.
[0023] As shown in FIG. 4, computing device 100 contains battery
enable/disable control circuitry 400. This circuitry 400, for
example, senses the simultaneous pressing of buttons 102, 108 and
114 and in response provides a battery disable signal. The
circuitry 400 may be part of an Application Specific Integrated
Circuit (ASIC) of an input/output controller of the device 100. In
operation, when all three buttons 102, 108 and 114 are pressed at
the same time, the disable line 602 goes low to indicate a disable
battery request provided to a battery protection circuit or battery
controller such as contained in the Dallas Semiconductor DS2760
battery monitor. Specifically, when each of the buttons 102 and 108
are pressed and these button communications are sensed, the
corresponding lines 102' and 108' go low, and when, and only when
such two lines go low, line 730' also goes low. Further, if button
114 is pressed, corresponding line 114' goes low. When, line 730'
is low, i.e., with buttons 102 and 104 being pressed, and line 114'
is low, i.e., with button 114 being pressed, line 740' also goes
low. When line 740' goes low, so does disable line 602. A low state
of the disable line 602 indicates a battery disable request. To
perform this disable battery sequence one may, with one hand, hold
a stylus 114, or some instrument capable of reaching recessed
button 114, and with it, press the recessed button 114, and with
two fingers on the other hand, press buttons 102 and 108. This sort
of two-handed operation ensures that a battery is being
disconnected intentionally. Generally, to perform this procedure
one may prefer to first place the device 100 on a flat surface
rather than grasping in one hand.
[0024] As shown in FIG. 4, OR gates 730 and 740 are part of the
device circuitry 400. Gate 730 is used to determine if both buttons
102 and 108 are being pressed. Gate 740 is used to determine if
both the reset button 114 is being pressed and the output of gate
730 indicates that the two buttons 102 and 108 are also being
pressed. If this gate arrangement determines that all such buttons
102, 108 and 114 are being pressed, then disable line 602 is set to
low. Further, other combinations of gates, other than what is shown
in FIG. 4, may be used to achieve the desired result. Resistors
810-840 serve as pull-up resistors in the circuitry of FIG. 4. When
line 740' is low, resistor 840 places transistor 880 into an open
collector state, allowing the disable line 602 to go low. Further,
when reset button 114 is pressed the enable line 604 goes low and
it is when the enable line goes low that signals the enables the
battery. The battery has a weak pull up on enable line 604. Diode
890 serves as a protection diode that guards back feeding on the
enable line 604. Further, diode 850 prevents current flow from
enable line 604 to line 114 when the battery is disable. If diode
850 was not there, and current was allowed to pass from enable line
604 to line 114, the battery would enable prematurely. It should be
understood that other circuit configurations may be utilized in
accordance with the disclosed techniques. It should also be
understood that the circuitry of FIG. 4 can be adapted to support
both a primary battery and a secondary battery.
[0025] It is contemplated that there are a variety of reasons for
ensuring that disabling a battery 300 is intentional. For example,
one may want to transfer the device 100 to a new user and may want
a quick and easy way of clearing the volatile memory. Another
example might be where the device 100 was to be put in storage for
an extended period of time without jeopardizing the battery 300 by
causing an under-voltage condition. Yet another example, might be
where the device 100 is not sufficiently responding to a soft reset
and disconnecting the battery 300 is the only option to adequately
reset the system 100. Because of the relative catastrophic results
of a hard reset, namely the loss of all data stored in volatile
memory, it is important that the hard reset procedures be such that
they are not accidentally performed. Further, unlike previous
portable computing devices, the illustrative system 100 provides a
user friendly design, i.e., no batteries to install, no doors to
open, no added switches or buttons, with a button sequence that all
but ensures that the disable battery procedure is not inadvertently
performed. This is done by simultaneous pressing of three buttons
with at least one of them recessed.
[0026] Also as shown in FIG. 4, when the reset button 114 is
pressed, line 114' goes low, as well as enable line 604. When
enable line 604 goes low, this is a signal to a battery protection
circuit, such as the DS2760 mentioned above, to enable the battery
connection. Further, device bottom 230 also contains a charging and
communications port 232. Although not shown, computing device 100
contains circuitry to sense the coupling between itself and a
device cradle. The coupling sensing occurs through recharge and
communications port 232. However, the coupling may occur through
other mechanisms, including, but not limited to, electrical,
mechanical, optical or magnetic detection mechanisms. When the
device 100 is coupled to a device cradle through port 232 the
enable line 604 goes low to indicate a battery enable request. The
recessed button 114 is pressed when the device 100 resides in the
device cradle.
[0027] Because portable computing devices are shipped with their
batteries in the disabled state, it is important to provide users
with a fast and easy method to enable the batteries. The disclosed
enabling techniques make it easier for users to enable the battery.
Since the battery is enabled automatically upon placement of the
device into the device cradle, such techniques allow a user to
enable the battery without having to read the instructions on how
to operate the portable computing device. Further, since users no
longer need to understand how to enable the battery, service calls
regarding battery enablement issues should be reduced.
[0028] The foregoing disclosure and description of the various
embodiments are illustrative and explanatory thereof, and various
changes in the button layout, button functionality, button
sequence, signals, components, devices, circuit elements, circuit
configurations, and signal connections, as well as in the details
of the illustrated circuitry and construction and method of
operation may be made without departing from the spirit and scope
of the invention.
* * * * *