In-device charging system and method for multi-chemistry battery systems

• US 6,479,962 B2
• Filed: 03/16/2001
• Issued: 11/12/2002
• Est. Priority Date: 03/16/2001
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Bean, Heather N, Bianchi, Mark J, Ziemkowski, Ted B
• Primary Examiner(s): TOATLEY, GREGORY J
• Application Number:
  US09/811,174
• Publication Number:
  US 20020130634A1
• Time in Patent Office: 606 Days
• Field of Search: 320/162, 320/106, 320/163
• US Class Current: 320/106
• CPC Class Codes: H02J 7/00047 with provisions for charging different types of batteries
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence

Abstract

A battery management system and method for an electronic device that may be powered by an AC source (using an AC adapter), or by a battery. The battery management system includes firmware configured to determine whether a battery coupled to the electronic device is rechargeable. The firmware is also coupled to and configured to control a charge switch. When the battery and an AC source are both coupled to the device, activating the charge switch causes a charging current to be applied from the AC source to the battery. The charge switch and firmware are configured to cause the charging current to not be applied to the battery if it is determined that the battery is not rechargeable.

Claims

1. A battery management system for an electronic device configured to be powered by either an AC-DC converted power source, or a battery, the battery management system comprising:

a battery connector configured to couple the battery to the electronic device so that the battery provides power to the electronic device when the electronic device is not coupled with the AC-DC converted power source;

an AC adapter connector configured to couple the AC-DC converted power source to the electronic device so that the AC-DC converted power source powers the electronic device;

firmware coupled to the battery connector, including a chemistry identifier configured to determine whether the battery is rechargeable; and

a charge switch coupled with and controlled by the firmware, where, when the electronic device is coupled to the battery and the AC-DC converted power source, activating the charge switch causes a charging current sourced by the AC-DC converted power source to be applied to the battery, where the firmware and charge switch prevent application of the charging current to the battery when the firmware determines that the battery is not rechargeable.

2. The battery management system of claim 1, where the charge switch prevents application of the charging current to the battery when the firmware determines that the battery is fully charged.

3. The battery management system of claim 1, where the charge switch prevents application of the charging current to the battery when the firmware determines that the battery is damaged.

4. The battery management system of claim 1, where the firmware is configured to read terminal voltage of the battery when the battery is subjected to a relative high load, and when the battery is subjected to a relative low load, for purposes of determining whether the battery is rechargeable.

5. The battery management system of claim 4, where the relative high load and low load voltage readings form a ratio, the firmware being configured to compare this ratio to known values for various battery types in order to determine whether the battery is rechargeable.

6. The battery management system of claim 1, further comprising a passive voltage sampler selectively coupled to the battery via a sampling switch, where activating the sampling switch causes the passive voltage sampler to sample and store terminal voltage of the battery.

7. The battery management system of claim 6, where the passive voltage sampler includes a capacitor that is charged by the battery upon activation of the sampling switch.

8. The battery management system of claim 6, where the firmware and passive voltage sampler are configured to sample battery terminal voltage when the electronic device is in a low load state, and where sampled voltage is subsequently read out and processed by the firmware.

9. The battery management system of claim 1, further comprising a loading switch configured to selectively couple a reference load to the battery.

10. The battery management system of claim 9, where the firmware is configured to control application of the reference load to the battery to facilitate determining whether the battery is rechargeable.

11. The battery management system of claim 1, where the charge switch is configured so that, even when the charge switch is activated, the charge switch automatically turns off when the charging current exceeds a predetermined maximum amount.

12. The battery management system of claim 1, where the charge switch is configured so that, even when the charge switch is activated, the charge switch automatically turns off when battery terminal voltage is less than a minimum threshold, the threshold being selected to inhibit charging of damaged or overly discharged batteries.

13. The battery management system of claim 1, where the battery management system is configured so that coupling the AC-DC converted power source to the electronic device reconfigures a terminal connection of the battery connector so that the battery is within a switchable charge path which is electrically parallel to the AC-DC converted power source.

20. The method of claim 11, further comprising preventing application of charging current to the battery if it is determined that the battery is damaged.

14. A battery charging method for use in connection with an electronic device that can be powered by rechargeable batteries, non-rechargeable batteries or an AC-DC converted power source, the method comprising:

providing a charging circuit configured to enable selective application of a charging current generated by the AC-DC converted power source to a battery coupled to the electronic device;

coupling the AC-DC converted power source to the electronic device so that the AC-DC converted power source powers the electronic device while simultaneously charging the battery upon activation of the charging circuit;

determining whether the battery is rechargeable; and

preventing application of the charging current to the battery if it is determined that the battery is not rechargeable.

15. The method of claim 14, where determining whether the battery is rechargeable includes measuring terminal voltage when the battery is subjected to a relative high load, and when the battery is subjected to a relative low load.

16. The method of claim 15, where high load and low load measurements are used to form a ratio, which is compared to known values for various battery types to determine whether the battery is rechargeable.

17. The method of claim 15, where measuring terminal voltage when the battery is subjected to a relative low load includes:

providing a passive voltage sampler selectively coupled to the battery by a sampling switch; and

activating the sampling switch to cause the passive voltage sampler to sample and store battery terminal voltage.

18. The method of claim 17, where a capacitor is used to sample and store battery terminal voltage.

19. The method of claim 14, further comprising preventing application of charging current to the battery if it is determined that the battery is fully charged.

21. A battery charging system for an electronic device capable of running on battery power or on power from a DC-converted AC source, the charging system comprising:

an AC adapter;

a battery connector having terminal leads configured to couple a battery to the electronic device; and

a switchable charging circuit coupled to the battery connector and AC-DC adapter, the switchable charging circuit being configured to determine whether the battery is rechargeable and, in response, control application of a charging current from the AC adapter to the terminal leads, the charging circuit being further configured to cut off the charging current if the charging current exceeds a maximum threshold amount.