Charging circuit and method, electronic device, and power supply unit

• US 20110279078A1
• Filed: 05/12/2011
• Published: 11/17/2011
• Est. Priority Date: 11/14/2008
• Status: Abandoned Application

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Hiramoto, Koichi, Tamura, Yuki, Hara, Yasushi
• Application Number:
  US13/067,161
• Publication Number:
  US 20110279078A1
• Time in Patent Office: Days
• US Class Current: 320/107
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters
• 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

Abstract

A charging circuit configured to charge a rechargeable battery includes an input unit configured to support forms of connection to an external power supply and to receive electric power supplied from the external power supply; a charge unit configured to supply the rechargeable battery with the electric power supplied from the input unit; a detection unit configured to detect the charge level of the rechargeable battery; and a charge control unit configured to control the charge unit so as to prevent the rechargeable battery from being supplied with the electric power supplied from the input unit supplied with the electric power from the external power supply through one of the forms of connection to the external power supply, in response to the charge level detected by the detection unit exceeding a threshold corresponding to the one of the forms of connection.

Claims

1. A charging circuit configured to charge a rechargeable battery, comprising:

an input unit configured to support a plurality of forms of connection to an external power supply and to receive electric power supplied from the external power supply;

a charge unit configured to supply the rechargeable battery with the electric power supplied from the input unit;

a detection unit configured to detect a charge level of the rechargeable battery; and

a charge control unit configured to control the charge unit so as to prevent the rechargeable battery from being supplied with the electric power supplied from the input unit supplied with the electric power from the external power supply through one of the forms of connection to the external power supply, in response to the charge level detected by the detection unit exceeding a threshold corresponding to said one of the forms of connection.

2. The charging circuit as claimed in claim 1, wherein:

the input unit includes

a first input unit configured to receive the electric power from the external power supply through a first one of the forms of connection; and

a second input unit configured to receive the electric power from the external power supply through a second one of the forms of connection, and

the charge control unit is configured to control the charge unit so as to prevent the rechargeable battery from being supplied with the electric power supplied from the first input unit, in response to the charge level detected by the detection unit exceeding a first threshold corresponding to the first input unit, and to control the charge unit so as to prevent the rechargeable battery from being supplied with the electric power supplied from the second input unit, in response to the charge level detected by the detection unit exceeding a second threshold corresponding to the second input unit.

3. The charging circuit as claimed in claim 2, wherein:

the first input unit is configured to receive the electric power supplied from the external power supply through a connection to a power feed connector configured to supply the electric power supplied from the external power supply,

the second input unit is configured to receive the electric power supplied from the external power supply through a connection to a connecting part of a stand upon placement of an electronic device including the charging circuit on the stand, the stand being configured to supply the electric power supplied from the external power supply, and

the second threshold corresponding to the second input unit is lower than the first threshold corresponding to the first input unit.

4. The charging circuit as claimed in claim 1, further comprising:

a storage unit configured to store control information including the forms of connection and respective thresholds thereof for the charge level of the rechargeable battery; and

a connection form identifying unit configured to identify the one of the forms of connection between the external power supply and the input unit,

wherein the charge control unit is configured to obtain the threshold corresponding to the one of the forms of connection identified by the connection form identifying unit from the control information stored by the storage unit.

5. An electronic device, comprising:

an input unit configured to support a plurality of forms of connection to an external power supply and to receive electric power supplied from the external power supply;

a charge unit configured to supply a rechargeable battery with the electric power supplied from the input unit, the rechargeable battery being used as a power supply for the electronic device;

a detection unit configured to detect a charge level of the rechargeable battery; and

a charge control unit configured to control the charge unit so as to prevent the rechargeable battery from being supplied with the electric power supplied from the input unit supplied with the electric power from the external power supply through one of the forms of connection to the external power supply, in response to the charge level detected by the detection unit exceeding a threshold corresponding to said one of the forms of connection.

6. The electronic device as claimed in claim 5, wherein:

the input unit includes

a first input unit configured to receive the electric power from the external power supply through a first one of the forms of connection; and

a second input unit configured to receive the electric power from the external power supply through a second one of the forms of connection, and

the charge control unit is configured to control the charge unit so as to prevent the rechargeable battery from being supplied with the electric power supplied from the first input unit, in response to the charge level detected by the detection unit exceeding a first threshold corresponding to the first input unit, and to control the charge unit so as to prevent the rechargeable battery from being supplied with the electric power supplied from the second input unit, in response to the charge level detected by the detection unit exceeding a second threshold corresponding to the second input unit.

7. The electronic device as claimed in claim 6, wherein:

the first input unit is configured to receive the electric power supplied from the external power supply through a connection to a power feed connector configured to supply the electric power supplied from the external power supply,

the second input unit is configured to receive the electric power supplied from the external power supply through a connection to a connecting part of a stand upon placement of the electronic device on the stand, the stand being configured to supply the electric power supplied from the external power supply, and

the second threshold corresponding to the second input unit is lower than the first threshold corresponding to the first input unit.

8. The electronic device as claimed in claim 5, further comprising:

a storage unit configured to store control information including the forms of connection and respective thresholds thereof for the charge level of the rechargeable battery; and

a connection form identifying unit configured to identify the one of the forms of connection between the external power supply and the input unit,

wherein the charge control unit is configured to obtain the threshold corresponding to the one of the forms of connection identified by the connection form identifying unit from the control information stored by the storage unit.

9. A method of charging a rechargeable battery configured to be used as a power supply for an electronic device including an input unit configured to support a plurality of forms of connection to an external power supply and to receive electric power supplied from the external power supply, the method comprising:

detecting a charge level of the rechargeable battery; and

preventing the rechargeable battery from being supplied with electric power supplied from the input unit supplied with the electric power from the external power supply through one of the forms of connection to the external power supply, in response to the charge level detected by said detecting exceeding a threshold corresponding to said one of the forms of connection.

10. The method as claimed in claim 9, wherein:

the input unit includes

a first input unit configured to receive the electric power from the external power supply through a first one of the forms of connection; and

a second input unit configured to receive the electric power from the external power supply through a second one of the forms of connection, and

said preventing prevents the rechargeable battery from being supplied with the electric power supplied from the first input unit, in response to the charge level detected by said detecting exceeding a first threshold corresponding to the first input unit, and to control the charge unit so as to prevent the rechargeable battery from being supplied with the electric power supplied from the second input unit, in response to the charge level detected by said detecting exceeding a second threshold corresponding to the second input unit.

11. The method as claimed in claim 10, wherein:

the first input unit is configured to receive the electric power supplied from the external power supply through a connection to a power feed connector configured to supply the electric power supplied from the external power supply,

the second input unit is configured to receive the electric power supplied from the external power supply through a connection to a connecting part of a stand upon placement of the electronic device on the stand, the stand being configured to supply the electric power supplied from the external power supply, and

the second threshold corresponding to the second input unit is lower than the first threshold corresponding to the first input unit.

12. The method as claimed in claim 9, further comprising:

identifying the one of the forms of connection between the external power supply and the input unit,

wherein said preventing obtains the threshold corresponding to the one of the forms of connection identified by said identifying from a storage unit prestoring control information including the forms of connection and respective thresholds thereof for the charge level of the rechargeable battery, and determines whether the charge level detected by said detecting exceeds the threshold corresponding to said one of the forms of connection using the charge level detected by said detecting and the obtained threshold.

13. A power supply unit, comprising:

a charge storage unit configured to receive electric power supplied from an external power supply and store an electric charge;

an input unit configured to support a plurality of forms of connection to the external power supply and to receive the electric power supplied from the external power supply;

a charge unit configured to supply the charge storage unit with the electric power supplied from the input unit;

a detection unit configured to detect a charge level of the charge storage unit; and

a charge control unit configured to control the charge unit so as to prevent the charge storage unit from being supplied with the electric power supplied from the input unit supplied with the electric power from the external power supply through one of the forms of connection to the external power supply, in response to the charge level detected by the detection unit exceeding a threshold corresponding to said one of the forms of connection.

14. The power supply unit as claimed in claim 13, wherein:

the input unit includes

a first input unit configured to receive the electric power from the external power supply through a first one of the forms of connection; and

a second input unit configured to receive the electric power from the external power supply through a second one of the forms of connection, and

the charge control unit is configured to control the charge unit so as to prevent the charge storage unit from being supplied with the electric power supplied from the first input unit, in response to the charge level detected by the detection unit exceeding a first threshold corresponding to the first input unit, and to control the charge unit so as to prevent the charge storage unit from being supplied with the electric power supplied from the second input unit, in response to the charge level detected by the detection unit exceeding a second threshold corresponding to the second input unit.

15. The power supply unit as claimed in claim 14, wherein:

the first input unit is configured to receive the electric power supplied from the external power supply through a connection to a power feed connector configured to supply the electric power supplied from the external power supply,

the second input unit is configured to receive the electric power supplied from the external power supply through a connection to a connecting part of a stand upon placement of the power supply unit on the stand, the stand being configured to supply the electric power supplied from the external power supply, and

the second threshold corresponding to the second input unit is lower than the first threshold corresponding to the first input unit.

16. The power supply unit as claimed in claim 13, further comprising:

a storage unit configured to store control information including the forms of connection and respective thresholds thereof for the charge level of the charge storage unit; and

a connection form identifying unit configured to identify the one of the forms of connection between the external power supply and the input unit,

wherein the charge control unit is configured to obtain the threshold corresponding to the one of the forms of connection identified by the connection form identifying unit from the control information stored by the storage unit.