U.S. patent application number 11/908299 was filed with the patent office on 2008-11-20 for portable battery operated power supply.
This patent application is currently assigned to Techtium, Ltd.. Invention is credited to Dror Manor, Guy Weinstein.
Application Number | 20080284370 11/908299 |
Document ID | / |
Family ID | 36953755 |
Filed Date | 2008-11-20 |
United States Patent
Application |
20080284370 |
Kind Code |
A1 |
Manor; Dror ; et
al. |
November 20, 2008 |
Portable Battery Operated Power Supply
Abstract
A portable battery-powered power supply or charger for use with
electronic devices containing a primary or secondary battery. In
order to control the current flow into and out of its battery, the
portable power supply uses a bidirectional charge controller. The
battery is installed in a housing which preferably has a single
connector port to which a flexible current lead may be plugged. The
bidirectional charge controller enables the battery either to
supply current to the electronic device, to charge the device's
internal battery, or it allows the battery, if it is a secondary
battery, to be charged by connection to an externally powered
charger, such as a wall mains adapter. Both of these functions are
achieved through a single connection port.
Inventors: |
Manor; Dror; (Herzliya,
IL) ; Weinstein; Guy; (Neve Monosson, IL) |
Correspondence
Address: |
HESLIN ROTHENBERG FARLEY & MESITI PC
5 COLUMBIA CIRCLE
ALBANY
NY
12203
US
|
Assignee: |
Techtium, Ltd.
Tel Aviv
IL
|
Family ID: |
36953755 |
Appl. No.: |
11/908299 |
Filed: |
March 10, 2006 |
PCT Filed: |
March 10, 2006 |
PCT NO: |
PCT/IL06/00318 |
371 Date: |
March 4, 2008 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60660353 |
Mar 11, 2005 |
|
|
|
Current U.S.
Class: |
320/103 ;
320/137 |
Current CPC
Class: |
H02J 7/342 20200101 |
Class at
Publication: |
320/103 ;
320/137 |
International
Class: |
H02J 7/00 20060101
H02J007/00; H02J 7/02 20060101 H02J007/02 |
Claims
1. A portable power supply for a battery operated electronic
device, comprising: a housing for containing a removable
rechargeable battery; a bidirectional charge controller controlling
current flow into and out of said rechargeable battery; and a
single connecting port for inputting current through said
bidirectional charge controller to said rechargeable battery from
an external power supply, and for outputting current from said
rechargeable battery through said bidirectional charge controller
to said electronic device.
2. A portable power supply according to claim 1 and wherein said
rechargeable battery has a first terminal voltage, and said device
requires a second voltage for operation, and said bidirectional
charge controller converts current output from said rechargeable
battery at said first terminal voltage to said second voltage for
powering said device.
3. A portable power supply according to claim 1 and wherein said
device has an internal rechargeable battery for operation, and
wherein said portable power supply battery has a first terminal
voltage, and said device battery has a second terminal voltage, and
said bidirectional charge controller converts current output from
said portable power supply battery at said first terminal voltage
to said second voltage for charging said device battery.
4. A portable power supply according to claim 2 and wherein said
first terminal voltage is lower than said second terminal
voltage.
5. A portable power supply according to claim 1 and wherein said
bidirectional charge controller determines periodically whether
said connecting port is connected to an external power supply to
receive charge current or to an electronic device to supply
current.
6. A portable power supply according to claim 5 and wherein said
bidirectional charge controller disconnects said rechargeable
battery from said connection port for a predetermined time
interval, and determines whether any voltage appearing on said
connection port remains essentially constant during said
predetermined time interval or shows a drop during said
predetermined time interval.
7. A portable power supply according to claim 6 and wherein said
predetermined time interval is less than 500 milliseconds.
8. A portable power supply according to claim 6 and wherein said
voltage drop during said predetermined time interval is at least
300 millivolts.
9. A portable power supply according to claim 3 and wherein said
first terminal voltage is lower than said second terminal
voltage.
10. A portable power supply according to claim 1 wherein a
rechargeable battery is removably disposed within said housing.
11. A portable power supply according to claim 2 wherein said
rechargeable battery is removably disposed within said housing.
12. A portable power supply according to claim 3 wherein a
rechargeable battery is removably disposed within said housing.
13. A portable power supply according to claim 4 wherein a
rechargeable battery is removably disposed within said housing.
14. A portable power supply according to claim 5 wherein a
rechargeable battery is removably disposed within said housing.
15. A portable power supply according to claim 6 wherein said
rechargeable battery is removably disposed within said housing.
16. A portable power supply according to claim 7 wherein said
rechargeable battery is removably disposed within said housing.
17. A portable power supply according to claim 8 wherein said
rechargeable battery is removably disposed within said housing.
18. A portable power supply according to claim 9 wherein said
rechargeable battery is removably disposed within said housing.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to the field of battery
equipped power supply systems for use with handheld electronic
devices, and especially portable battery operated power supplies
for charging the batteries of handheld electronic devices.
BACKGROUND OF THE INVENTION
[0002] The proliferation of portable battery powered devices, such
as cellular telephones, video cameras, portable laptop computers,
and the like, has increased dramatically in the last several years
and this trend is expected to continue. These devices typically use
a rechargeable battery that is built into the device to provide the
needed power. The length of time that the battery powers the device
is dependent primarily upon the size of the battery and the number
of energy consuming features built into the device. For instance,
in response to consumer demand, cell phone manufacturers often
incorporate into the phones features such as the ability to send
and receive digital pictures and/or text messages, and even
real-time video transmissions. Unfortunately, the inclusion of
these features usually places additional demands on the
rechargeable batteries that power the cell phones. The net result
is that cell phone run times are becoming shorter due to the
increased power demands. At the same time that the electrical
demand placed on the battery is increasing, the size and weight of
cell phones is decreasing. As the size of the cell phone is
reduced, the size of the battery compartment built into the cell
phone is also generally reduced. The combination of these two
trends, i.e. increased electrical demand and reduced battery size,
often causes cell phone users to experience a lost telephone call
or data transmission due to the depletion of the phone battery at
an inopportune moment. An additional trend that complicates
resolution of this problem is that most cell phones require a
battery that has specific size and shape characteristics. In order
to encourage consumers to purchase replacement batteries from the
cell phone manufacturer, the cell phones are made with batteries
that have unique shapes, locking mechanisms, voltage requirements,
etc. Furthermore, the recharging port built into the cell phones
limit the type of charger that can be connected to the cell phone.
Collectively, these factors limit the consumer's ability to readily
replace the depleted battery with another power source.
[0003] Numerous attempts have been made to develop a versatile
portable power supply for cellular telephones. For example, U.S.
Pat. No. 6,127,801 to D. Manor, for "Battery Pack Assembly",
discloses a power supply that includes a battery pack and a base
unit which has bidirectional circuitry. In U.S. Pat. No. 6,479,963
to D. Manor and G. Weinstein, for "Rechargeable Battery Packs",
there is described a rechargeable battery pack for use with
cellular telephones or other portable devices, including a
conventional rechargeable battery for powering the device, and a
user-replaceable primary cell for recharging the rechargeable cell
when desired by the user, thus acting as a built-in charger for the
device. This battery pack uses as its additional energy source a
replaceable primary cell or battery, which when depleted, needs to
be replaced by a fresh battery. In another example, U.S. Pat. No.
6,709,784 to O. Resch, for "Back-up Battery for a Cellular
Telephone" there is disclosed a battery pack that can be plugged
into a cellular phone's contact to recharge the phone's built-in
rechargeable battery and/or to directly power the cell phone. This
invention does not provide any voltage converting circuitry to
match the battery pack output voltage to that required for charging
the phone's rechargeable battery, and relies on the internal charge
control circuits of the phone to ensure correct voltage
compatibility. Furthermore, the battery is preferably packaged with
the plug that allows the battery pack to be connected to the phone.
Consequently, when the battery is depleted, the entire battery
pack, including the plug, must be discarded, increasing consumer
costs.
[0004] Therefore, there exists a need for an auxiliary direct
current power source that uses a commonly available battery that
the consumer can readily insert into and remove from a reusable
housing, and that can be either a readily available primary cell or
battery, or a secondary cell or battery with the added option of
recharging the secondary cell or battery inside the device's
housing, using the device's usual charging method. The power supply
needs to be lightweight, volume-efficient and easily adaptable to a
wide array of cell phones or other handheld electronic devices that
utilize batteries of various shapes and sizes.
[0005] The disclosures of each of the publications mentioned in
this section and in other sections of the specification, are hereby
incorporated by reference, each in its entirety.
BRIEF SUMMARY OF THE INVENTION
[0006] The present invention seeks to provide, according to a first
preferred embodiment of the present invention, a new portable
battery-powered power supply or charger for use with electronic
devices containing a rechargeable battery. In order to control the
current flow into and out of its battery, the portable power supply
uses a bidirectional battery charge control system, as fully
described in co-pending PCT Patent Application by the present
inventors for "Bidirectional Battery Charge Controller", herewith
incorporated by reference in its entirety. The battery is installed
in a separate housing, connected to the portable electronic device
preferably by means of a flexible lead, and plugged thereby into
the external charging input of the portable electronic device. In
such an embodiment, the bidirectional charge controller is
preferably built into the housing containing the battery, usually
on a printed circuit board, and enables the battery either to
supply current to the device like an external battery powered power
supply, or, if it is a secondary battery, allows the battery to be
charged by connection to an externally powered charger, such as a
wall mains adapter or a car cigarette lighter adapter. The battery
can thus be considered to behave as a compact portable external
charger for the device, for use, for instance, in situations when
the main battery of the device is depleted without access to a
mains recharging source of power.
[0007] Control of the current flow into and out of the battery is
performed by the bidirectional charge controller. The battery
powered power supply of the present invention can be powered by one
or more cells, though the most convenient embodiment may be for a
single cell to be used. The bidirectional charge controller is such
that an external charger, such as a mains wall plug charger,
generally used to charge the main rechargeable battery of the
electronic device, can also recharge the battery in the portable
battery powered power supply of the present invention, on condition
that it is a secondary battery.
[0008] The bidirectional charge controller also acts as a voltage
converter, to convert the battery voltage to the voltage generally
required for powering the electronic device, or for charging the
device's rechargeable battery. The device's battery voltage is
usually, though not always, higher than the battery voltage of the
battery powered power supply. The ability of the power supply
battery to charge the electronic device's battery is particularly
useful since readily available primary or secondary cells can be
used in the battery powered power supply, in situations where the
main battery is depleted without any access to mains power supply
for conventional recharging. Furthermore, the bidirectional charge
controller is preferably microprocessor controlled, and is
programmed to be able to detect the battery chemistry of the
battery, and to disable charging current flow into the battery if
primary cell chemistry is detected. Likewise, in the reverse
direction, the microprocessor algorithm is preferably able to
regulate the charging current from the battery to the electronic
device rechargeable battery such that optimal energy transfer is
obtained for every stage of the device battery's state of
charge.
[0009] It should be noted that the terms battery and cell, though
formally distinct (a battery technically being an assembly of more
than one cell), are sometimes used in this application
interchangeably in relation to the power supply's battery, since
the "battery" may either contain a single cell, or several cells.
However, the invention is understood to be applicable regardless of
whether a cell or a battery is used as the "battery", and the
meaning is understood to be sometimes interchanged, as in the
widespread popular use of the term battery, when in fact only a
single cell is intended.
[0010] There is thus provided in accordance with a preferred
embodiment of the present invention, a portable power supply for a
battery operated electronic device, comprising:
(i) a housing for containing a battery, (ii) a rechargeable battery
removably disposed within the housing, (iii) a bidirectional charge
controller controlling current flow into and out of the
rechargeable battery, and (iv) a single connecting port for
inputting current through the bidirectional charge controller to
the rechargeable battery from an external power supply, and for
outputting current from the rechargeable battery through the
bidirectional charge controller to the electronic device.
[0011] The rechargeable battery preferably has a first terminal
voltage, and the device preferably requires a second voltage for
operation, and the bidirectional charge controller is such as to
convert current output from the rechargeable battery at the first
terminal voltage to the second voltage for powering the device.
[0012] In accordance with another preferred embodiment of the
present invention the device preferably has an internal
rechargeable battery for operation, and the portable power supply
battery has a first terminal voltage, and the device battery a
second terminal voltage, and the bidirectional charge controller
converts current output from the portable power supply battery at
the first terminal voltage to the second voltage for charging the
device battery.
[0013] In either of the two previous embodiments, the first
terminal voltage is preferably lower than the second terminal
voltage.
[0014] There is further provided in accordance with still another
preferred embodiment of the present invention, a portable power
supply as described above, and wherein the bidirectional charge
controller determines periodically whether the connecting port is
connected to an external power supply to receive charge current or
to an electronic device to supply current.
[0015] In order to achieve this, the bidirectional charge
controller preferably disconnects the rechargeable battery from the
connection port for a predetermined time interval, and determines
whether any voltage appearing on the connection port remains
essentially constant during the predetermined time interval or
shows a drop during the predetermined time interval. The
predetermined time interval is preferably less than 500
milliseconds, and the voltage drop during the predetermined time
interval is preferably at least 300 millivolts.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The present invention will be understood and appreciated
more fully from the following detailed description, taken in
conjunction with the drawings in which:
[0017] FIG. 1 is a schematic block circuit diagram of a portable,
battery operated power supply, constructed and operative according
to a preferred embodiment of the present invention, when supplying
current to an electronic device, thereby giving an energy boost to
the rechargeable battery in the electronic device when needed;
[0018] FIG. 2 shows the operation of the portable power supply of
FIG. 1, when being charged from an external power source through
the bidirectional charge controller to the power supply's
rechargeable battery;
[0019] FIG. 3 illustrates schematically a portable battery-powered
power supply according to a further preferred embodiment of the
present invention, showing its method of connection to an
electronic device; and
[0020] FIG. 4 is a block circuit diagram of the power control
system of the bidirectional battery charge controller used in the
present invention, showing a preferred architecture which enables
some of the various features of the power supply of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0021] Reference is now made to FIGS. 1 and 2, which are schematic
block circuit diagrams showing the two modes of operation of the
portable battery-powered power supply of the present invention,
using the bidirectional charge controller to control the two modes.
These figures illustrate the overall arrangement of a battery
powered power supply 10 incorporating a bidirectional charge
controller 12, and with its own internal battery power source 14,
constructed and operative according to a preferred embodiment of
the present invention.
[0022] In FIG. 1, the power supply 10 is shown being used to power
or charge a portable electronic device 20, which has its own
built-in rechargeable battery 22, which can preferably be a Li-ion
type of battery, and also circuitry 26 to perform the device's
function. An internal protection circuit 24 is generally provided
to protect the electronic device's built-in rechargeable battery
against harmful conditions, including overcharge, over-discharge
and excessive temperature.
[0023] In FIG. 2, the battery 14 of the power supply 10 is shown
being charged by connection of an external power source 30, such as
a wall mains charger, or an adapter for the power outlet in a car.
An important feature of the present invention is that a single
output port 28, is used both for drawing current from the battery
14 of the portable power supply, and for charging the battery 14 of
the portable power supply by means of an external source. This
feature is rendered possible only by the use of the bidirectional
charge controller 12 built into the portable power supply. The
operation of the bidirectional charge controller circuitry is
therefore described in some detail below.
[0024] The power supply battery 14 preferably comprises a
replaceable, readily available standard-sized cell or cells, for
inputting power to the power system of the electronic device 20.
However, this external charging unit of the present invention
differs in two major aspects from those described in the prior art
mentioned in the Background Section: [0025] (i) Firstly, the
battery 14 can comprise either a primary cell or cells, or a
rechargeable cell or cells. [0026] (ii) Secondly, the battery 14 is
connected to the external environment through the bidirectional
charge controller 12, which monitors and controls the flow of
current both out of the battery to the power system of the
electronic device 20, and also from an external power source such
as a wall charger into the battery 14. In addition, the
bidirectional charger 12 preferably acts as a voltage converter to
convert the generally comparatively low battery voltage to the
higher voltage required by the power system of the electronic
device 20, and conversely to convert the comparatively higher
charging voltage from, for instance, an external wall plug charging
adapter, to a lower voltage for charging the battery 14. If the
battery 14 has a higher terminal voltage than that of the
electronic device's rechargeable battery 22, the converter operates
accordingly. Usually, a charging controller is included as part of
the electronic device circuitry, or within the wall adapter, in
order to control the rate of charging from the external wall
adapter. This function is included at the input 16 to the
bidirectional charge controller of the present invention. This
means that the energy transferred through the bidirectional charge
controller 12 can flow in two directions--hence the term
"bidirectional charger".
[0027] The bidirectional charge controller must be able to
accommodate and accordingly control both of these two possible
operational applications of the battery 14 of the power supply. In
order to fulfill both of these functions efficiently, the
bidirectional charge controller 12 is preferably
microprocessor-based. It provides a current interface between on
the one hand, the single-cell or multiple-cell battery 14, which
preferably contains either a secondary cell such as a Nickel Metal
Hydride (NiMH) or a Nickel Cadmium (NiCd), or a primary battery or
cell, such as an alkaline battery or a fuel cell, and on the other
hand, the single-cell or multiple-cell battery of the electronic
device 20, which preferably contains a Li-ion battery. The power
supply battery side is conveniently called the "low voltage side",
and the rechargeable battery of the electronic device is
conveniently called the "high voltage side", since the nominal
operating voltage of the device battery is generally higher than
that of the power supply battery. The bidirectional charge
controller is able to transfer current and to control battery
charging, either from low-voltage to high-voltage side when current
is drawn from the battery 14, or from high-voltage to low-voltage
side when an external power source such as a wall plug charger 30
is connected as the high voltage side.
[0028] Reference is now made to FIG. 3 which schematically
illustrates a portable battery-powered power supply according to a
further preferred embodiment of the present invention, showing the
battery 50 installed and ready for use with the electronic device
54, which contains its own rechargeable battery. The battery 50 is
shown packaged into a separate housing 52, connected to the
portable device preferably by means of a flexible lead 56, and
plugged thereby into the external charging input 58 of the portable
device. In this embodiment, the bidirectional charge controller is
also built into the housing containing the battery, preferably on a
printed circuit board 60. The power supply preferably has only a
single connector port 28, which is used both for inputting current
to charge the battery 50 and outputting current to the electronic
device 54.
[0029] The bidirectional charge controller of the portable external
charger preferably incorporates all of the functions of the
bidirectional charge controller, as described in co-pending PCT
Patent Application by the present inventors for "Bidirectional
Battery Charge Controller". However, two functions are of
particular importance. Firstly, it is important that the unit
senses the battery chemistry of the battery inserted into the
housing to prevent charging of a primary cell. This is particularly
important for the portable power supply application because of the
exposed nature of the housing 102, which could easily come into
contact with the user's body during charging, or even be held in
the user's hand. Also, it is important that the unit efficiently
converts the voltage of the current being controlled depending on
whether the auxiliary battery is supplying current or is being
charged. This embodiment is important since it involves a portable
power source which can be used to power any device having a
compatible connector. Thus, since the manufacturer has no control
over the type of device the auxiliary battery of the unit is to
power, there may be need for additional functions to be
incorporated into the control circuits, such as checking the status
of the battery of the electronic device to determine that it is
suitable to be charged, or providing a visual signal to the user,
such as by means of a LED, that the unit contains a cell ready to
supply current, and others.
[0030] Furthermore, the battery of a portable external charger has
a number of operational differences from the internal auxiliary
batteries described in the embodiments of the co-pending
application for hybrid battery use. For instance, before the unit
is connected to the electronic device, it has no electrical contact
with the power source of the battery of the electronic device.
Therefore, the bidirectional charge controller has to be completely
self-powered, by means of the cell 14 inserted into the housing.
The bidirectional charge controller circuit 60 is thus designed to
have a very low standby current load, which can be arranged to be
only several tens of microamperes, thus enabling the unit to be
ready for use, after insertion of a battery, for periods of months
without depleting the battery. Furthermore, even under these
conditions, and when not yet connected to a load for charging, it
must generate a higher voltage on its output port 28, suitable for
effecting a charge, so that the electronic device detects the
presence of a charging device the moment the lead is plugged into
the external charging input 58 on the device.
[0031] Furthermore, wall plug and similar external power supply
chargers are generally designed to operate with simpler
characteristics than those of the bidirectional charge controller
of the present invention. Usually, external wall chargers behave as
a constant current source, simply pushing charge current into the
external charging input of the device, and the charging circuits of
the electronic device itself control this inflow of charge current
until the battery is full. The charging algorithm of the
bidirectional charge controller of the portable power supply of the
present embodiment may thus also preferably be constructed to
supply current to the device with similar characteristics. Thus for
instance, it will not have to perform any "stop charging" routine
when the main battery approaches full charge, since the internal
charge control circuitry of the electronic device is designed to
follow the entire charge profile. On the other hand, for charging
current flowing through the bidirectional charge controller from
the wall plug charger to the portable external charger battery,
there is still need for a charge current algorithm which will
properly control the charging profile of the power supply
battery.
[0032] Since the bidirectional charge controller of the portable
external charger enables it to be used either for charging or for
being charged through the same connector, and without any user
intervention to select either of these roles, it is important that
the portable external charger can determine for itself whether it
is connected to a device as a load, or to a wall charger for
recharging of its own battery. A simple voltage test at the
connector is insufficient, since a wall charger and the converted
voltage to power the device may have similar levels. Therefore,
according to another preferred embodiment of the present invention,
the portable external charger is provided with a function checking
routine, whereby the output voltage at the connector 28 is removed
at regular intervals for a short time, typically every few seconds
for a duration of the order of a few tenths of a second, and
typically less than 0.5 sec., and the connector voltage is
measured. If a measurement shows an essentially steady voltage,
then it is clear that the portable power supply is connected to a
wall charger or another external source of power for charging of
its own battery 50. If on the other hand, the voltage falls during
the measurement to a lower level, typically by 0.3 volts or more,
then it is clear that the portable power supply is connected to an
electronic device for recharging the battery of the device, and the
bidirectional charge controller control functions are switched
accordingly.
[0033] The battery 50 is preferably a secondary cell, and the use
of the bidirectional charge controller circuit then also enables
the cell to be charged when desired by connecting the portable
power supply to the output socket of an external charger, such as a
wall plug charger, or to a car dashboard socket. The portable power
supply then has a double and reciprocal function--it can charge the
electronic device by connection to the device's charging input
connector, and it can be charged itself by connection to an
external wall charger output connector. If the device's charging
input connector has the opposite gender to the external wall
charger output connector, as is the usual arrangement, there will
be need for a male-to-female adapter, or alternatively, separate
connection leads for the two operations. If a sexless connector is
used for the charging function, then no such adapter will be
needed.
[0034] Alternatively and preferably, a primary cell can be used as
the battery 50, and the unit then provides all of the advantages of
the control functions of the bidirectional charge controller, such
as voltage sensing, voltage conversion and charge rate control, but
since the battery cannot be recharged, it has to be replaced when
depleted.
[0035] The embodiment shown in FIG. 3 is particularly convenient,
since it allows the use of a single AA-sized cell, which is widely
available and of low cost. The voltage converter circuitry then
ensures that the comparatively low voltage of the auxiliary cell is
boosted to that required by the electronic device circuitry when
the unit is supplying current, and effectively down-converts the
external charger voltage output so as to limit the charging current
when the cell in the power supply is being charged. It is to be
understood though that such an external charger battery can also
preferably contain more than one cell.
[0036] Reference is now made to FIG. 4, which is a block circuit
diagram of the power control system of the bidirectional battery
charge controller used in the battery powered power supply of the
present invention, showing the architecture which enables the
operation of the features of the present invention. Although the
block diagram of FIG. 4 is for a bidirectional charge controller
for use in a hybrid battery application for a portable computer,
for instance, the main features are also relevant for the power
supply application of the present invention, and will be mentioned
hereinbelow.
[0037] The embodiment shown in FIG. 4 is the more common situation
wherein the battery powering the electronic device has a higher
voltage than the power supply battery. However, the reverse
situation can also be found in some devices, wherein the battery
powering the device has a lower voltage than the power supply
battery and in such a case, some of the circuit functions of the
blocks of the embodiment of FIG. 4 need to be reversed, but the
overall functional structure is similar.
[0038] The current to or from the battery 81 flows into the
bi-directional DC-DC Power Stage 84, which is a bidirectional
voltage conversion unit, allowing current flow from the auxiliary
battery 81 to the electronic device battery 85, or vice versa, and
converting the terminal voltage accordingly, depending on the
direction of the current flow.
[0039] The magnitude of the current flow into or out of the battery
81 is preferably measured by the bidirectional current sensor 83,
which senses the current flowing through the inductor in the
bi-directional DC-DC converter 84. Since some designs of current
sensors need to know the direction of flow, the direction in which
the current is sensed is reversed in accordance with the signal
received from the Control block 88.
[0040] The Battery 85 for powering the electronic device 89,
comprising one or more cells, usually contains rechargeable Li-Ion
cells. As is usual in such portable electronic devices, a wall
charger 90 is provided for charging, if so desired, from an
external voltage source, such as a mains power source. The Portable
Electronic Device can also receive energy from the Battery 81. When
used in the portable power supply of the present invention, the
electronic device 89, and its batteries 90 are separated from the
circuit parts of the bidirectional charge controller by the
connection lead 56 of FIG. 3, linking blocks 84 and 85. Likewise,
the external voltage source 90, besides being able to charge the
electronic device's internal battery 85, can also be connected
directly to this lead 56, for charging the battery 81 of the
portable power supply.
[0041] The Control block 88 is the main control unit of the
Bi-Directional Battery Charge Controller, and controls the overall
operation of the entire circuit. It receives inputs corresponding
to the voltage, current, and also preferably temperature of each
cell, and uses the above-mentioned algorithms to control the entire
system, including the desired level and direction of current flow.
The desired level of current is determined by the Control block 88.
Control levels output from the Control Box 88 or the direction of
current flow can be used to shut down the circuit. Data
communication between the portable device 89 and the Control block
88 can be achieved by use of the standard data communication lines
adopted in such devices, and are used to communicate user-generated
commands from the device, and to send control-generated messages
back to the user.
[0042] A number of additional control elements are preferably
operative within the architecture of FIG. 4. A Temperature Sense
Block 86 may preferably be connected to the battery 81, and senses
preferably the temperature of each of the cells in the battery 81.
The Current Controller 87 controls the level of current through the
DC-DC converter by sending PWM pulses of the appropriate duty
cycle, using a current mode control cycle, to the drivers in the
Bi-Directional DC-DC Power Stage 84. The PWM pulses are output
according to the desired current level setting received from the
control block 88. The current controller 87 may also receive inputs
of the system clock from the control block 88, and of the actual
current level from the current sensor 83.
[0043] It is appreciated by persons skilled in the art that the
present invention is not limited by what has been particularly
shown and described hereinabove. Rather the scope of the present
invention includes both combinations and subcombinations of various
features described hereinabove as well as variations and
modifications thereto which would occur to a person of skill in the
art upon reading the above description and which are not in the
prior art.
* * * * *