Charging circuit for controlling a charging parameter of a rechargeable battery

• US 6,861,823 B2
• Filed: 07/14/2003
• Issued: 03/01/2005
• Est. Priority Date: 08/17/2001
• Status: Expired due to Term

• Current Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Original Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Inventors: Bucur, Constantin
• Primary Examiner(s): Tso, Edward H.
• Application Number:
  US10/618,901
• Publication Number:
  US 20040012375A1
• Time in Patent Office: 596 Days
• Field of Search: 320/137, 320/139, 320/140, 320/141, 320/143, 320/145, 320/166
• US Class Current: 320/145
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/0018 using separate charge circuits
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters

Abstract

A voltage mode battery charging system is provided that includes a battery current control section, a battery voltage control section, and a power control section. The battery current control section and battery voltage control section each generate signals indicative of the battery charging current and battery voltage, respectively. The power control section generates a signal indicative of the power available from an adapter source. Each of these signals is combined at common node, and if any of these sections exceeds a threshold, battery charging current is decreased.

Claims

1. A charging circuit for controlling a charging parameter provided to a rechargeable battery, said charging circuit comprising;

a first path configured to monitor a battery charging current provided to said battery;

a second path configured to monitor a battery charging voltage provided to said battery; and

a regulating circuit configured to reduce said charging parameter provided to said battery if said battery charging current exceeds a battery charging current threshold;

wherein said first path comprises a first amplifier configured to receive a first monitoring signal representative of said battery charging current and a first comparison signal representative of said battery charging current threshold, and to provide a first control signal to said regulating circuit based on a difference between said first monitoring signal and said first comparison signal.

2. The charging circuit of claim 1, wherein said first control signal has a nonzero value if said first monitoring signal exceeds said first comparison signal.

3. A charging circuit for controlling a charging parameter provided to a rechargeable battery, said charging circuit comprising:

a first path configured to monitor a battery charging current provided to said battery;

a second path configured to monitor a battery charging voltage provided to said battery; and

a regulating circuit configured to reduce said charging parameter provided to said battery if said battery charging current exceeds a battery charging current threshold;

wherein said second path comprises a second amplifier configured to receive a second monitoring signal representative of said battery charging voltage and a second comparison signal representative of said battery voltage threshold, and to provide a second control signal to said regulating circuit based on a difference between said second monitoring signal and said second comparison signal.

4. The charging circuit of claim 3, wherein said second control signal has a nonzero value if said second monitoring signal exceeds said second comparison signal.

5. A charging circuit for controlling a charging parameter provided to a rechargeable battery, said charging circuit comprising:

a first path configured to monitor a battery charging current provided to said battery;

a second path configured to monitor a battery charging voltage provided to said battery; and

a regulating circuit configured to reduce said charging parameter provided to said battery if said battery charging current exceeds a battery charging current threshold;

wherein said regulating circuit comprises a comparator configured to provide a PWM control signal to control said charging parameter, said comparator reducing a duty cycle of said PWM control signal if said battery charging current exceeds a battery charging current threshold.

6. The charging circuit of claim 5, wherein said comparator reduces said duty cycle of said PWM control signal if said battery charging voltage exceeds a battery voltage threshold.

7. An electronic device that may be powered by a DC power source or a rechargeable battery, said electronic device comprising:

a DC to DC converter configured to provide a charging parameter to said battery;

a charging circuit configured to control said charging parameter, said charging circuit comprising;

a first path configured to monitor a battery charging current provided to said battery;

a second path configured to monitor a battery charging voltage provided to said battery;

a regulating circuit configured to reduce said charging parameter provided to said battery if said battery charging current exceeds a battery charging current threshold; and

a third path configured to monitor a supply current provided to said battery and to system circuitry of said electronic device, wherein said regulating circuit is further configured to reduce said charging parameter provided to said battery if said supply current exceeds a supply current threshold.

8. An electronic device that may be powered by a DC power source or a rechargeable battery, said electronic device comprising:

a DC to DC converter configured to provide a charging parameter to said battery;

a charging circuit configured to control said charging parameter, said charging circuit comprising;

a first path configured to monitor a battery charging current provided to said battery;

a second path configured to monitor a battery charging voltage provided to said battery; and

a regulating circuit configured to reduce said charging parameter provided to said battery if said battery charging current exceeds a battery charging current threshold;

wherein said first path comprises a first amplifier configured to receive a first monitoring signal representative of said battery charging current and a first comparison signal representative of said battery charging current threshold, and to provide a first control signal to said regulating circuit based on a difference between said first monitoring signal and said first comparison signal.

9. The electronic device of claim 8, wherein said first control signal has a nonzero value if said first monitoring signal exceeds said first comparison signal.

10. The electronic device of claim 8, wherein said first monitoring signal is based on a voltage drop across a sense resistor, said sense resistor coupled to an output terminal of said DC to DC converter.

11. An electronic device that may be powered by a DC power source or a rechargeable battery, said electronic device comprising:

a DC to DC converter configured to provide a charging parameter to said battery;

a charging circuit configured to control said charging parameter, said charging circuit comprising;

a first path configured to monitor a battery charging current provided to said battery;

a second path configured to monitor a battery charging voltage provided to said battery; and

a regulating circuit configured to reduce said charging parameter provided to said battery if said battery current exceeds a battery charging current threshold;

wherein said second path comprises a second amplifier configured to receive a second monitoring signal representative of said battery charging voltage and a second comparison signal representative of said battery voltage threshold, and to provide a second control signal to said regulating circuit based on a difference between said second monitoring signal and said second comparison signal.

12. The electronic device of claim 11, wherein said second control signal has a nonzero value if said second monitoring signal exceeds said second comparison signal.

13. An electronic device that may be powered by a DC power source or a rechargeable battery, said electronic device comprising:

a DC to DC converter configured to provide a charging parameter to said battery;

a charging circuit configured to control said charging parameter, said charging circuit comprising;

a first path configured to monitor a battery charging current provided to said battery;

a second path configured to monitor a battery charging voltage provided to said battery; and

a regulating circuit configured to reduce said charging parameter provided to said battery if said battery charging current exceeds a battery charging current threshold;

wherein said regulating circuit comprises a comparator configured to provide a PWM control signal to said DC to DC converter to control said charging parameter, said comparator reducing a duty cycle of said PWM control signal if said battery charging current exceeds a battery charging current threshold.

14. The electronic device of claim 13, wherein said comparator reduces said duty cycle of said PWM control signal if said battery charging voltage exceeds a battery voltage threshold.