Apparatus and method for discharging and charging a multiple battery arrangement

• US 6,081,096 A
• Filed: 08/29/1997
• Issued: 06/27/2000
• Est. Priority Date: 10/31/1995
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Barkat, Shakil H., Ng, Richard, Mottier, Matthew D.
• Primary Examiner(s): Berhane, Adolf Deneke
• Assistant Examiner(s): TIBBITS, PIA FLORENCE
• Application Number:
  US08/920,408
• Time in Patent Office: 1,033 Days
• Field of Search: 320/124, 320/125, 320/126, 320/160, 320/162, 320/163, 320/DIG. 11, 307/64, 307/66, 307/56
• US Class Current: 320/124
• CPC Class Codes: G06F 1/26 Power supply means, e.g. regulation thereof for memories G11C
• CPC Class Codes: H02J 7/0024 Parallel/serial switching of connection of batteries to charge or load circuit
• CPC Class Codes: H02J 9/061 for DC powered loads
• CPC Class Codes: H04B 1/3883 Arrangements for mounting batteries or battery chargers

Abstract

A device (100) includes detachable main and auxiliary batteries (101, 102) and a circuit (310) for discharging and charging the batteries (101, 102). Discharging is accomplished by an auxiliary switch (420) that connects the auxiliary battery (102) to power the device (100), a detector (422), and a main switch (424) that connects the main battery (101) to power the device (100), without interruption, when the auxiliary battery (102) drops below a predetermined voltage (508) as determined by a detector (422). Charging is performed by switches (440, 442, 446), an internal charger (444), and a controller (306). When both batteries (101, 102) are attached, the controller (306) uses the switches (440, 442, 446) to select and couple charging current generated by the internal charger (444) to the main battery (101). Once charged, the controller (306) switches to charge the auxiliary battery (102).

Claims

1. An electronic device comprising:

a charger to generate a charging current;

a first contact to couple to a first battery;

a second contact to couple to a second battery;

a third contact to couple to the first battery, the third contact to communicate a first voltage level when the first battery is attached thereto;

a fourth contact to couple to the second battery, the fourth contact to communicate a second voltage level when the second battery is present;

a first switch comprising a first output, a second output and an input, the first output coupled to the first contact, the second output coupled to the second contact, and the input coupled to the charger, the first switch to selectively couple the input to one of the first output to supply the charging current to the first contact and the second output to supply the charging current to the second contact;

a second switch coupled to the third contact and the fourth contact; and

a controller coupled to the first switch and the second switch, the controller to control the second switch to couple one of the third contact to the controller to determine presence of the first battery from detection of the first voltage level and the fourth contact to the controller to determine presence of the second battery from detection of the second voltage level.

2. An electronic device according to claim 1 further comprising the first battery and the second battery, the first battery having a first electrochemical cell and a first thermistor, the first thermistor having a first end coupled to the first electrochemical cell and a second end coupled to the third contact, the second battery having a second electrochemical cell and a second thermistor, and the second thermistor having a first end coupled to the second electrochemical cell and a second end coupled to the fourth contact.

3. An electronic device according to claim 1

further comprising a coupler to connect to an external power supply, the coupler coupled to the charger;

and

wherein the charger comprises a current regulator and a charging controller having a current source, the current source is coupled to the coupler and the current regulator, the current regulator is coupled to the first switch.

4. An electronic device according to claim 1 wherein the electronic device is a radiotelephone.

5. An electronic device comprising:

a charger to generate a charging current;

a first contact to couple to a first battery;

a second contact to couple to a second battery;

a third contact coupled to the first battery, the third contact to communicate a first set of charging characteristics;

a fourth contact coupled to the second battery, the fourth contact to communicate a second set of charging characteristics;

a first switch comprising a first output, a second output, and an input, the first output coupled to the first contact, the second output coupled to the second contact, and the input coupled to the charger, the first switch to selectively couple the input to one of the first output to supply the charging current to the first contact and the second output to supply the charging current to the second contact;

a second switch coupled to the third contact and the fourth contact; and

a controller coupled to the second switch and the charger, the controller to control the second switch to couple one of the third contact to the controller to read the first set of charging characteristics and the fourth contact to the controller to read the second set of charging characteristics.

6. An electronic device according to claim 5 further comprising the first battery and the second battery, the first battery having a first memory containing the first set of charging characteristics, the first memory coupled to the third contact, the second battery having a second memory containing the second set of charging characteristics, and the second memory coupled to the fourth contact.

7. An electronic device according to claim 5

further comprising a coupler to connect to an external power supply, the coupler coupled to the charger;

and

wherein the charger comprises a current regulator and a charging controller having a current source, the current source is coupled to the coupler and the current regulator, the current regulator is coupled to the first switch.

8. An electronic device according to claim 5 wherein the electronic device is a radiotelephone.

9. An electronic device according to claim 5 wherein the second switch comprises a multiplexer/demultiplexer.

10. A method of charging a plurality of batteries detachably coupled to an electronic device, the method comprising the steps of:

charging a first battery of the plurality of batteries when the first battery is attached to the electronic device and one of the first battery is attached and not fully charged, a second battery of the plurality of batteries is detached, and the second battery is attached and fully charged;

charging the second battery when the second battery is attached to the electronic device and one of the second battery is attached and not fully charged, the first battery is detached, and the first battery is attached and fully charged.

11. A method according to claim 10 further comprising the step of:

interrupting charging of the first battery and the second battery when the first battery and the second battery are detached.

12. A method according to claim 10 wherein the steps of charging further comprise the substeps of:

maintenance charging the first battery when the first battery is attached and fully charged and the second battery is detached;

maintenance charging the second battery when the second battery is attached and fully charged and the first battery is detached; and

maintenance charging the first and second batteries when the first and second batteries are attached and fully charged.

13. An electronic device comprising:

a first battery and a second battery, the first battery having a first capacity, the second battery having a second capacity, the second capacity differing from the first capacity;

a first contact to couple to the first battery;

a second contact to couple to the second battery;

a charger to generate a charging current; and

a first switch comprising a first output, a second output, and an input, the first output coupled to the first contact, the second output coupled to the second contact, and the input coupled to the charger, the first switch to selectively couple the input to one of the first output to supply the charging current to the first contact and the second output to supply the charging current to the second contact.

14. An electronic device according to claim 13

further comprising a coupler to connect to an external power supply, the coupler coupled to the charger;

and

wherein the charger comprises a current regulator and a charging controller having a current source, the current source is coupled to the coupler and the current regulator, the current regulator is coupled to the first switch.

15. An electronic device according to claim 13 wherein the electronic device is a radiotelephone.

16. An electronic device according to claim 13 wherein the first switch comprises a plurality of MOSFETs.

17. An electronic device according to claim 13 wherein the first and second batteries are detachable.

18. An electronic device comprising:

a first detachable battery having a first electrochemical cell, a first thermistor, and a first memory containing a first set of characteristics;

a second detachable battery having a second electrochemical cell, a second thermistor, and a second memory containing a second set of characteristics;

a first switch having an input, a select port, a first output coupled to the first electrochemical cell, and a second output coupled to the second electrochemical cell, the first switch controllable via its select port to connect its input to one of its first and second outputs;

a second switch having an output, a select port, a first input coupled to the first thermistor, and a second input coupled to the second thermistor, the second switch controllable via its select port to connect its output to one of its first and second inputs;

a third switch having an output, a select port, a first input coupled to the first memory, and a second input coupled to the second memory, the third switch controllable via its select port to connect its output to one of its first and second inputs;

a charger coupled to the input of the first switch, the charger to supply charging current; and

a controller coupled to the charger, the outputs of the second and third switches, and the select ports of the first, second, and third switches, the controller performing the following steps;

controlling the second switch to alternate connection of the first and second thermistors to the controller,

controlling the third switch to connect the first memory to the controller in response to detection of a predetermined voltage level across the first thermistor,

reading the first set of characteristics from the first memory,

configuring the charger according to the first set of characteristics,

controlling the first switch to connect the charging current to the first electrochemical cell,

controlling the third switch to connect the second memory to the controller,

reading the second set of characteristics from the second memory,

configuring the charger according to the second set of characteristics, and

controlling the first switch to connect the charging current to the second electrochemical cell.

19. An electronic device according to claim 18 wherein the electronic device is a radiotelephone.

20. An electronic device according to claim 18 wherein one of the second switch and the third switch comprises a multiplexer/demultiplexer.