Dual battery pack charging in a computer system

• US 5,955,867 A
• Filed: 07/29/1997
• Issued: 09/21/1999
• Est. Priority Date: 07/29/1997
• Status: Expired due to Term

• Current Assignee: Dell USA LP (Dell Technologies Inc.)
• Original Assignee: Dell USA LP (Dell Technologies Inc.)
• Inventors: Cummings, John A., Kates, Barry K.
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): TOATLEY, GREGORY J
• Application Number:
  US08/902,097
• Time in Patent Office: 784 Days
• Field of Search: 320/107, 320/119, 320/160
• US Class Current: 320/107
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/0024 Parallel/serial switching of connection of batteries to charge or load circuit

Abstract

A system for charging dual battery packs. The system includes a charger for supplying current to charge a first battery pack when the first battery pack is electrically coupled to the computer system. The charger supplies current to charge a second battery pack when the second battery pack is electrically coupled to the computer system. The system also includes a charge controller, such as a keyboard controller executing a program stored in a memory, for controlling the charging of the first battery pack and the second battery pack such that the charger charges the first battery pack to a first level, the charger charges the second battery pack to a second level, and the charger simultaneously charges the first battery pack and the second battery pack when the first battery pack is charged above the first level and below a third level and the second battery pack is charged above the second level and below a fourth level. Each battery pack includes a processor, an associated memory, back to back FETs, and lithium ion cells.

Claims

1. A computer system comprising:

a processor;

a memory electrically coupled to the processor;

a charger for supplying current to charge a first battery pack when the first battery pack is electrically coupled to the computer system, the charger for supplying current to charge a second battery pack when the second battery pack is electrically coupled to the computer system;

a charge controller for controlling the charging of the first battery pack and the second battery pack such that the charger charges the first battery pack to a first level, the charger charges the second battery pack to a second level, and the charger simultaneously charges the first battery pack and the second battery pack when the first battery pack is charged above the first level and below a third level and the second battery pack is charged above the second level and below a fourth level;

wherein the charger supplies current to the first battery pack via a first switch to charge the first battery pack, the charge controller making conductive the first switch to charge the first battery pack;

wherein the charger supplies current to the second battery pack via a second switch to charge the second battery pack the charge controller making conductive the second switch to charge the second battery pack;

wherein the charge controller makes a third switch and a fourth switch non conductive when the charger is simultaneously charging the first battery pack and the second battery pack, the computer system capable of being powered by current supplied via the third switch from the first batter pack, the computer system capable of being powered by current supplied via the fourth switch from the second battery pack.

2. The computer system of claim 1 wherein:

the first and second levels are of a range of approximately 60 percent to 90 percent of a full charge.

3. The computer system of claim 1 wherein the third and fourth levels are approximately fully charged.

4. The computer system of claim 1 wherein:

the conductivity of the first switch is controlled by a first battery processor included with the first battery pack;

the charge controller makes conductive the first switch by directing the first battery processor to make conductive the first switch;

the conductivity of the second switch is controlled by a second battery processor included with the second battery pack; and

the charge controller makes conductive the second switch by directing the second battery processor to make conductive the second switch.

5. The computer system of claim 1 wherein:

when the computer system is being powered from an alternating current source and when the charger is simultaneously charging the first battery pack and the second battery pack, in response to the computer system ceasing to be powered from the alternating current source, the first switch and the second switch become non conducting and the third switch and the fourth switch become conductive to power the computer system from the first battery pack and the second battery pack,

after the third switch and the fourth switch becoming conductive, the charge controller making one of the third switch or the fourth switch non conductive to cease powering the computer system from one of the first battery pack or the second battery pack, respectively.

6. A computer system comprising:

a processor;

a memory electrically coupled to the processor;

a charger for supplying current to charge a first battery pack when the first battery pack is electrically coupled to the computer system, the charger for supplying current to charge a second battery pack when the second battery pack is electrically coupled to the computer system;

a charge controller for controlling the charging of the first battery pack and the second battery pack such that the charger charges the first batter pack to a first level, the charger charges the second battery pack to a second level, and the charger simultaneously charges the first battery pack and the second battery pack when the first battery pack is charged above the first level and below a third level and the second battery pack is charged above the second level and below a fourth level;

wherein the charge controller includes;

a second memory; and

a second processor electrically coupled to the second memory, the second processor controlling the charging of the first battery pack and the second battery pack according to a program stored in the second memory, the processor monitoring the charge level of the first battery pack, the second processor monitoring the charge level of the second battery pack.

7. The computer system of claim 6 wherein the second memory includes a Basic Input/Output System (BIOS).

8. The computer system of claim 6 wherein the second processor includes a keyboard controller.

9. The computer system of claim 6 wherein:

the second processor directs a first battery processor included with the first battery pack to control the charging of the first battery pack;

the second processor directs a second battery processor included with the second battery pack to control the charging of the second battery pack.

10. The computer system of claim 6 wherein:

the first and second levels are of a range of approximately 60 percent to 90 percent of a full charge.

11. The computer system of claim 6 wherein the third and fourth levels are approximately fully charged.

12. The computer system of claim 6 wherein:

the charger supplies current to the first battery pack via a first switch to charge the first battery pack, the charge controller making conductive the first switch to charge the first battery pack; and

the charger supplies current to the second battery pack via a second switch to charge the second battery pack, the charge controller making conductive the second switch to charge the second battery pack.

13. The computer system of claim 12 wherein:

the conductivity of the first switch is controlled by a first battery processor included with the first battery pack;

the charge controller makes conductive the first switch by directing the first battery processor to make conductive the first switch;

the conductivity of the second switch is controlled by a second battery processor included with the second battery pack; and

the charge controller makes conductive the second switch by directing the second battery processor to make conductive the second switch.

14. A method for charging battery packs comprising:

supplying current to a first battery pack from a charger to charge the first battery pack;

determining that the first battery pack is charged to a first level;

supplying current to a second battery pack from the charger to charge the second battery pack to a second level; and

determining that the second battery pack is charged to a second level;

supplying current simultaneously to the first battery pack and to the second battery pack when the first battery pack is charged above the first and charged below a third level and the second battery pack is charged above the second level and charged below a fourth level;

wherein the supplying of current to the first battery pack includes making conductive a first switch, the current to the first battery pack being supplied via the first switch;

wherein the supplying of current to the second battery pack includes making conductive a second switch, the current to the second battery pack being supplied via the second switch;

wherein the supplying of current simultaneously to the first and the second battery packs includes making conductive the first and second switches;

wherein the first battery pack supplies current to a power input of a computer system to power the computer system via a third switch; and

wherein the second battery pack supplies current to the power input to power a computer system via a fourth switch.

15. The method of claim 14 wherein:

the supplying of current to the first battery pack includes making conductive the third switch; and

the supplying of current to a second battery pack includes making conductive the fourth switch.

16. The method of claim 14 wherein:

the supplying of current simultaneously to the first battery pack and the second battery pack includes making the third and fourth switches non conductive.

17. The method of claim 16 further comprising:

supplying current from an alternating current adapter to the power input of the computer system;

removing the supply of current from the alternating current adapter to the power input of the computer system during the supplying of current simultaneously to the first battery pack and to the second battery pack; and

in response to the removing of the supply of current, making conductive the third and fourth switches and making non conductive the first and the second switches.

18. The method of claim 14 further comprising:

making the first switch non conductive when the first battery pack is determined to be charged to the first level;

determining that the first battery pack is charged to a third level;

making the first switch non conductive when the first battery pack is determined to be charged to the third level; and

determining that the second battery pack is charged to a fourth level; and

making the second switch non conductive when the second battery pack is determined to be charged to the fourth level.

19. The method of claim 14 wherein:

the supplying of current to the first battery pack includes supplying current at a first level;

the supplying current simultaneously to the first battery pack and to the second battery pack includes supplying current to the first battery pack at a second level; and

the second level is less than half of the first level.

20. A computer system comprising:

a system processor;

a memory electrically coupled to the system processor;

a first battery pack capable of powering the computer system including powering the system processor;

a second battery pack capable of powering the computer system including powering the system processor;

a charger supplying current to the first battery pack to charge the first battery pack, the charger supplying current to the second battery pack to charge the second battery pack; and

a charge controller for controlling the charging of the first battery pack and the second battery pack such that the charger charges the first battery pack to a first level, the charger charges the second battery pack to a second level, and the charger simultaneously charges the first battery pack and the second battery pack when the first battery pack is charged above the first level and below a third level and the second battery pack is charged above the second level and below a fourth level;

wherein the charge controller includes;

a second memory; and

a second processor electrically coupled to the second memory, the second processor controlling the charging of the first battery pack and the second battery pack according to a program stored in the second memory, the second processor monitoring the charge level of the first battery pack, the second processor monitoring the charge level of the second battery pack.

21. The computer system of claim 20 further comprising:

a first switch, the charger supplying current to the first battery pack via the first switch to charge the first battery pack, the charge controller making the first switch conductive to charge the first battery pack; and

a second switch, the charger supplying current to the second battery pack via the second switch to charge the second battery pack, the charge controller making the second switch conductive to charge the second battery pack.

22. The computer system of claim 20 wherein the second memory includes a Basic Input/Output System (BIOS).

23. The computer system of claim 20 wherein the second processor includes a keyboard controller.

32. The computer system of claim 21 further wherein:

the first battery pack includes a first battery processor, the first battery processor controlling the conductivity of the first switch;

the second battery pack includes a second battery processor, the second battery processor controlling the conductivity of the second switch;

the charge controller makes conductive the first switch by directing the first battery processor to make conductive the first switch; and

the charge controller makes conductive the second switch by directing the second battery processor to make conductive the second switch.

33. The computer system of claim 20 wherein:

the first and second levels are of a range of approximately 60 percent to 90 percent of fully charged.

34. The computer system of claim 20 wherein the third and fourth levels are approximately fully charged.

24. A computer system comprising:

a system processor;

a memory electrically coupled to the system processor;

a first battery pack capable of powering the computer system including powering the system processor;

a second battery pack capable of powering the computer system including powering the system processor;

a charger supplying current to the first battery pack to charge the first battery pack, the charger supplying current to the second battery pack to charge the second battery pack;

a charge controller for controlling the charging of the first battery sack and the second battery pack such that the charger charges the first battery pack to a first level, the charger charges the second battery pack to a second level, and the charger simultaneously charges the first batter pack and the second battery pack when the first battery pack is charged above the first level and below a third level and the second battery pack is charged above the second level and below a fourth level;

a first switch, the charger supplying current to the first battery pack via the first switch to charge the first battery pack, the charge controller making the first switch conductive to charge the first battery pack;

a second switch, the charger supplying current to the second battery pack via the second switch to charge the second battery pack the charge controller making the second switch conductive to charge the second battery pack;

a power input for receiving direct current for powering the computer system including powering the system processor;

a third switch, the first battery pack supplying current to the power input to power the computer system via the third switch; and

a fourth switch, the second battery pack supplying current to the power input to power the computer system via the fourth switch.

25. The computer system of claim 24 wherein:

the third switch is conductive when the charger is charging the first battery pack to the first level;

the fourth switch is conductive when the charger is charging the second battery pack to the second level.

26. The computer system of claim 24 wherein:

the first switch and the third switch are back-to-back FETs; and

the second switch and the fourth switch are back-to-back FETs.

27. The computer system of claim 24 wherein:

the first battery pack includes the first switch and the third switch; and

the second battery pack includes the second switch and the fourth switch.

28. The computer system of claim 24 wherein

wherein the third switch and the fourth switch are non conductive when the charger is simultaneously charging the first battery pack and the second battery pack.

29. The computer system of claim 28 further comprising:

an AC adapter electrically coupled to the power input, the AC adapter supplying direct current to the power input to power the computer system including powering the system processor; and

wherein when the charger is simultaneously charging the first battery pack and the second battery pack and when the power input ceases to receive direct current from the AC adapter to power the computer system, the third switch and the fourth switch become conductive and the first switch and second switch become non conductive.

30. The computer system of claim 29 wherein:

after the third switch and the fourth switch become conductive and the first switch and the second switch become non conductive, the charge controller makes one of the third switch or the fourth switch non conductive to cease powering the computer system from one of the first battery packs or the second battery packs respectively.

31. The computer system of claim 29 wherein:

the first battery pack includes a first battery processor;

the second battery pack includes a second battery processor;

the first and second battery processors each receives an AC available signal indicating whether the AC adapter is supplying direct current to the power input; and

when the charger is simultaneously charging the first battery pack and the second battery pack, in response to receiving an indication via the AC available signal that the AC adapter is no longer supplying current to the power input, the first battery processor makes non conductive the first switch and makes conductive the third switch and the second battery processor makes non conductive the second switch and makes conductive the fourth switch.

35. The computer system of claim 24 further wherein:

the first battery pack includes a first battery processor, the first battery processor controlling the conductivity of the first switch;

the second battery pack includes a second battery processor, the second battery processor controlling the conductivity of the second switch;

the charge controller makes conductive the first switch by directing the first battery processor to make conductive the first switch; and

the charge controller makes conductive the second switch by directing the second battery processor to make conductive the second switch.

36. The computer system of claim 24 wherein:

the first and second levels are of a range of approximately 60 percent to 90 percent of fully charged.

37. The computer system of claim 24 wherein the third and fourth levels are approximately fully charged.