POWER SUPPLY CIRCUIT, CHARGING UNIT HAVING THE POWER SUPPLY CIRCUIT, AND POWER SUPPLY METHOD

• US 20100231175A1
• Filed: 12/04/2007
• Published: 09/16/2010
• Est. Priority Date: 02/14/2007
• Status: Abandoned Application

• Current Assignee: RICOH Electronic Devices Co., Ltd. (Nisshinbo Holdings Incorporated)
• Original Assignee: Ricoh Company Limited
• Inventors: Noda, Ippei
• Application Number:
  US12/293,773
• Publication Number:
  US 20100231175A1
• Time in Patent Office: Days
• US Class Current: 320/162
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 16/006 of fuel cells with rechargeable batteries
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 2207/40 adapted for charging from various sources, e.g. AC, DC or multivoltage
• 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 50/10 using inductive coupling
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• 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: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A power supply circuit supplying power to a charge control circuit charging a secondary battery is disclosed. The power supply circuit includes a direct-current power supply configured to generate and output a predetermined voltage; and a DC-DC converter configured, to detect the voltage of the secondary battery, convert the predetermined voltage input from the direct-current power supply into a voltage according to the detected voltage of the secondary battery, and output the converted voltage to the charge control circuit.

Claims

1. A power supply circuit supplying power to a charge control circuit charging a secondary battery, the power supply circuit comprising:

a direct-current power supply configured to generate and output a predetermined voltage; and

a DC-DC converter configured to detect a voltage of the secondary battery, convert the predetermined voltage input from the direct-current power supply into a voltage according to the detected voltage of the secondary battery, and output the converted voltage to the charge control circuit.

2. The power supply circuit as claimed in claim 1, wherein the DC-DC converter is configured to convert and output the predetermined voltage input from the direct-current power supply so that a difference between the converted voltage and the detected voltage of the secondary battery is a predetermined value.

3. The power supply circuit as claimed in claim 1, wherein the DC-DC converter is configured to generate a predetermined minimum voltage required for the charge control circuit to operate irrespective of the voltage of the secondary battery and output the generated predetermined minimum voltage to the charge control circuit in response to the voltage of the secondary battery being less than or equal to a predetermined value.

4. The power supply circuit as claimed in claim 1, wherein the direct-current power supply is a fuel cell generating and outputting the predetermined voltage.

5. The power supply circuit as claimed in claim 1, wherein the direct-current power supply is a solar battery generating and outputting the predetermined voltage.

6. The power supply circuit as claimed in claim 1, wherein the DC-DC converter is a step-up switching regulator.

7. The power supply circuit as claimed in claim 1, further comprising:

an additional direct-current power supply configured to generate a predetermined additional voltage,

wherein the DC-DC converter is configured to output only the additional voltage to the charge control circuit as the power in response to the additional voltage being greater than or equal to a predetermined value, and to convert the predetermined voltage from the direct-current power supply into the voltage according to the detected voltage of the secondary battery, and output the converted voltage and the additional voltage to the charge control circuit as the power in response to the additional voltage being less than the corresponding predetermined value.

8. The power supply circuit as claimed in claim 1, further comprising:

an additional direct-current power supply configured to generate a predetermined additional voltage,

wherein the DC-DC converter is configured to output the additional voltage to the charge control circuit as the power in response to the additional voltage being greater than or equal to a predetermined value, and to convert the predetermined voltage from the direct-current power supply into the voltage according to the detected voltage of the secondary battery, and output the converted voltage to the charge control circuit as the power in response to the additional voltage being less than the corresponding predetermined value.

9. The power supply circuit as claimed in claim 1, wherein the DC-DC converter is configured to stop converting and outputting the predetermined voltage in response to detecting, from the voltage of the secondary battery, the secondary battery being fully charged.

10. A charging unit charging a secondary battery, the charging unit comprising:

a charge control circuit configured to charge the secondary battery; and

a power supply circuit configured to supply power to the charge control circuit,

wherein the power supply circuit includes

a direct-current power supply configured to generate and output a predetermined voltage; and

a DC-DC converter configured to detect a voltage of the secondary battery, convert the predetermined voltage input from the direct-current power supply into a voltage according to the detected voltage of the secondary battery, and output the converted voltage to the charge control circuit.

11. The charging unit as claimed in claim 10, wherein the DC-DC converter is configured to convert and output the predetermined voltage input from the direct-current power supply so that a difference between the converted voltage and the detected voltage of the secondary battery is a predetermined value.

12. The charging unit as claimed in claim 10, wherein the DC-DC converter is configured to generate a predetermined minimum voltage required for the charge control circuit to operate irrespective of the voltage of the secondary battery and output the generated predetermined minimum voltage to the charge control circuit in response to the voltage of the secondary battery being less than or equal to a predetermined value.

13. The charging unit as claimed in claim 10, wherein the direct-current power supply is a fuel cell generating and outputting the predetermined voltage.

14. The charging unit as claimed in claim 10, wherein the direct-current power supply is a solar battery generating and outputting the predetermined voltage.

15. The charging unit as claimed in claim 10, wherein the DC-DC converter is a step-up switching regulator.

16. The charging unit as claimed in claim 10, wherein:

the power supply circuit further comprises an additional direct-current power supply configured to generate a predetermined additional voltage; and

the DC-DC converter is configured to output only the additional voltage to the charge control circuit as the power in response to the additional voltage being greater than or equal to a predetermined value, and to convert the predetermined voltage from the direct-current power supply into the voltage according to the detected voltage of the secondary battery, and output the converted voltage and the additional voltage to the charge control circuit as the power in response to the additional voltage being less than the corresponding predetermined value.

17. The charging unit as claimed in claim 10, wherein:

the power supply circuit further comprises an additional direct-current power supply configured to generate a predetermined additional voltage; and

the DC-DC converter is configured to output the additional voltage to the charge control circuit as the power in response to the additional voltage being greater than or equal to a predetermined value, and to convert the predetermined voltage from the direct-current power supply into the voltage according to the detected voltage of the secondary battery, and output the converted voltage to the charge control circuit as the power in response to the additional voltage being less than the corresponding predetermined value.

18. The charging unit as claimed in claim 10, wherein the DC-DC converter is configured to stop converting and outputting the predetermined voltage in response to detecting, from the voltage of the secondary battery, the secondary battery being fully charged.

19. The charging unit as claimed in claim 10, wherein the DC-DC converter and the charge control circuit are integrated into a single IC.

20. A method of supplying power to a charge control circuit charging a secondary battery, the method comprising:

detecting a voltage of the secondary battery; and

converting a predetermined voltage input from a direct-current power supply into a voltage according to the detected voltage of the secondary battery, and outputting the converted voltage to the charge control circuit.

21-25. -25. (canceled)