Circuit for charging supplemental battery in portable electronic device

• US 6,864,664 B2
• Filed: 06/06/2003
• Issued: 03/08/2005
• Est. Priority Date: 06/06/2003
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.), Sony Electronics Inc. (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.), Sony Electronics Inc. (Sony Group Corp.)
• Inventors: Clift, Graham
• Primary Examiner(s): Tso, Edward H.
• Application Number:
  US10/455,896
• Publication Number:
  US 20040257039A1
• Time in Patent Office: 641 Days
• Field of Search: 320/103, 320/112, 320/127, 320/128, 320/137, 320/162, 323/273, 323/274, 323/281
• US Class Current: 320/128
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/342 The other DC source being a battery actively interacting with the first one, i.e. battery to battery charging with circuits for polarity protection H02J7/0034
• CPC Class Codes: H02M 1/0045 Converters combining the concepts of switch-mode regulation and linear regulation, e.g. linear pre-regulator to switching converter, linear and switching converter in parallel, same converter or same transistor operating either in linear or switching mode

Abstract

A charge pump IC and LDO are provided between the main power supply of a portable electronic device and a supplemental battery to control charge current and voltage to the supplemental battery using a small internally-packaged circuit.

Claims

1. A circuit for charging a supplemental battery of a portable electronic device providing a main power supply, comprising:

a charge pump integrated circuit (IC) receiving voltage from the main power supply; and

a low drop out linear regulator (LDO) receiving voltage from the charge pump IC and outputting voltage to the supplemental battery.

2. The circuit of claim 1, comprising the supplemental battery, wherein the supplemental battery is a Lithium ion (Li-ion) battery.

3. The circuit of claim 1, comprising the supplemental battery, wherein the charge pump IC and LDO are contained on a single substrate.

4. The circuit of claim 3, wherein the substrate is mounted on a housing of the portable electronic device.

5. The circuit of claim 1, wherein the circuit is capacitive based.

6. The circuit of claim 1, further comprising a switch between the charge pump IC and the LDO for selectively adding resistance to the circuit.

7. The circuit of claim 6, wherein the switch is a field effect transistor (FET).

8. The circuit of claim 7, further comprising a microcontroller for sending a pre-charge signal to the FET to add resistance into the circuit based at least in part on a voltage of the supplemental battery.

9. The circuit of claim 1, further comprising a microcontroller electrically connected to the charge pump IC to send a control signal thereto based at least in part on a voltage of the supplemental battery.

10. The circuit of claim 3, wherein the substrate is housed with the supplemental battery in module form to establish a self-contained battery assembly with embedded charging circuitry.

11. A portable electronic device, comprising:

at least one primary power source;

at least one supplemental power source;

charging means internal to the device for controlling the charging of the supplemental power source, the charging means including constant current means coupled to maximum voltage means for providing a constant current to the supplemental power source up to a first voltage, and then providing constant voltage to the supplemental power source.

12. The device of claim 11, wherein the charging means does not include an inductive-based boost regulator.

13. The device of claim 11, wherein the constant current means includes a charge pump integrated circuit (IC) receiving voltage from the primary voltage source, and the maximum voltage means includes a low drop out linear regulator (LDO) receiving voltage from the charge pump IC and outputting voltage to the supplemental power source.

14. The device of claim 13, wherein the supplemental power source is a Lithium ion (Li-ion) battery.

15. The device of claim 13, wherein the charge pump IC and LDO are contained on a single substrate.

16. The device of claim 15, wherein the substrate is mounted on a housing of the portable electronic device.

17. The device of claim 15, wherein the substrate is housed with the supplemental battery in module form to establish a self-contained battery assembly with embedded charging circuitry.

18. The device of claim 13, further comprising a switch between the charge pump IC and the LDO for selectively adding resistance to the circuit.

19. The device of claim 18, wherein the switch is a field effect transistor (FET).

20. The device of claim 19, further comprising a microcontroller for sending a pre-charge signal to the FET to add resistance into the circuit based at least in part on a voltage of the supplemental power source.

21. The device of claim 13, further comprising a microcontroller electrically connected to the charge pump IC to send a control signal thereto based at least in part on a voltage of the supplemental power source.

22. A portable electronic device, comprising:

electronic circuitry;

a main battery powering at least portions of the circuitry;

a supplemental battery powering at least portions of the circuitry at least from time to time;

a current limiting device limiting a charge current to the supplemental battery to no more than a maximum charge current; and

a voltage limiting device limiting a charge voltage to the supplemental battery to no more than a maximum charge voltage.

23. The device of claim 22, wherein the current limiting device is a charge pump integrated circuit (IC) receiving voltage from the main battery, and the voltage limiting device is a low drop out linear regulator (LDO) receiving voltage from the charge pump IC and outputting voltage to the supplemental battery.

24. The device of claim 23, wherein the supplemental battery is a Lithium ion (Li-ion) battery.

25. The device of claim 23, wherein the charge pump IC and LDO are contained on a single substrate mounted on a housing of the portable electronic device.

26. The device of claim 23, wherein the substrate is housed with the supplemental battery in module form to establish a self-contained battery assembly with embedded charging circuitry.

27. The device of claim 23, further comprising a field effect transistor (FET) and a microcontroller for sending a pre-charge signal to the FET to add resistance into the circuit based at least in part on a voltage of the supplemental battery.

28. The device of claim 23, further comprising a microcontroller electrically connected to the charge pump IC to send a control signal thereto based at least in part on a voltage of the supplemental battery.