Method and electronic circuit for efficient battery wake up charging

• US 8,350,534 B2
• Filed: 07/19/2009
• Issued: 01/08/2013
• Est. Priority Date: 09/21/2000
• Status: Expired due to Fees

• Current Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Original Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Inventors: Niculae, Marian, Bucur, Constantin
• Primary Examiner(s): Muralidar, Richard V
• Application Number:
  US12/505,514
• Publication Number:
  US 20090278499A1
• Time in Patent Office: 1,269 Days
• Field of Search: 320/152, 320157-159, 320162-164
• US Class Current: 320/162
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 5/00 Circuit arrangements for transfer of electric power between ac networks and dc networks H02J3/36 takes precedence
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0018 using separate charge circuits
• CPC Class Codes: H02J 7/0025 Sequential battery discharge in systems with a plurality of batteries
• 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 7/0069 Charging or discharging for charge maintenance, battery initiation or rejuvenation
• CPC Class Codes: H02J 7/00714 in response to battery charging or discharging current
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage
• CPC Class Codes: H02J 7/34 Parallel operation in networks using both storage and other dc sources, e.g. providing buffering H02J7/14 takes precedence
• CPC Class Codes: H02J 9/061 for DC powered loads
• 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
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A method for efficiently charging a battery. The method includes producing a first signal having a voltage level dependent on the voltage of the battery, comparing the voltage level of the first signal with a settable voltage representative of a maximum battery charging current, and producing a second signal representative of a charging current to be provided to the battery, the second signal having a voltage level selected to be the lower voltage level between the first signal and the settable voltage.

Claims

1. A wake up charging circuit for providing a wake up charging current to a battery, said wake up charging circuit comprising:

a signal processing circuit for receiving a first predetermined reference signal and a voltage sensing signal indicating a voltage of said battery, and for generating an output signal according to said first predetermined reference signal and said voltage sensing signal;

a comparison circuit coupled to said signal processing circuit for comparing said output signal to a second predetermined reference signal, and for generating a wake up control signal to control said wake up charging current; and

an error amplifier for receiving said wake up control signal and a current sensing signal indicative of said wake up charging current and for generating an error signal to maintain said wake up charging current at a level based on said wake up control signal.

2. The wake up charging circuit as claimed in claim 1, wherein said first predetermined reference signal represents a minimum wake up charging current.

3. The wake up charging circuit as claimed in claim 1, wherein said second predetermined reference signal represents a maximum allowable wake up charging current.

4. The wake up charging circuit as claimed in claim 1, wherein said wake up control signal has a voltage level that is equal to a lower voltage level selected between said output signal and said second predetermined reference signal.

5. The wake up charging circuit as claimed in claim 1, wherein said wake up control signal increases as said voltage of said battery increases until said wake up control signal reaches said second predetermined reference signal.

6. The wake up charging circuit as claimed in claim 1, wherein said signal processing circuit comprises an amplifier for receiving said first predetermined reference signal and said voltage sensing signal via an input pin of said amplifier.

7. The wake up charging circuit as claimed in claim 6, wherein said input pin of said amplifier receives said first predetermined reference signal via a first resistor and receives said voltage sensing signal via a second resistor, and wherein said wake up control signal increases linearly with said voltage of said battery by a constant factor whose value is determined by said first and second resistors.

8. A wake up charging circuit for providing a wake up charging current to a battery, said wake up charging circuit comprising:

a control circuit for receiving a voltage sensing signal indicative of a voltage of said battery and a first predetermined reference signal representing a minimum wake up charging current of said battery, and for generating a wake up charging control signal having a voltage level dependent at least on said voltage sensing signal and said first predetermined reference signal; and

an error amplifier for receiving said wake up control signal and a current sensing signal indicative of said wake up charging current and for generating an error signal to maintain said wake up charging current at a level based on said wake up control signal.

9. The wake up charging circuit as claimed in claim 8, wherein said control circuit further receives a second predetermined reference signal representing a maximum allowable wake up charging current.

10. The wake up charging circuit as claimed in claim 9, wherein said wake up control signal increases as said voltage of said battery increases until said wake up control signal reaches said second predetermined reference signal.

11. The wake up charging circuit as claimed in claim 9, wherein said control circuit comprises:

a signal processing circuit for generating an output signal according to said first predetermined reference signal and said voltage sensing signal; and

a comparison circuit coupled to said signal processing circuit for comparing said output signal to said second predetermined reference signal, and for generating said wake up control signal.

12. The wake up charging circuit as claimed in claim 11, wherein said wake up control signal has a voltage level that is equal to a lower voltage level selected between said output signal and said second predetermined reference signal.

13. The wake up charging circuit as claimed in claim 8, wherein said control circuit comprises an amplifier for receiving said first predetermined reference signal and said voltage sensing signal via an input pin of said amplifier.

14. The wake up charging circuit as claimed in claim 13, wherein said input pin of said amplifier receives said first predetermined reference signal via a first resistor and receives said voltage sensing signal via a second resistor, and wherein said wake up control signal increases linearly with said voltage of said battery by a constant factor whose value is determined by said first and second resistors.