Power supply apparatus

• US 8,547,054 B2
• Filed: 02/27/2008
• Issued: 10/01/2013
• Est. Priority Date: 02/28/2007
• Status: Expired due to Fees

• Current Assignee: JX Nippon Oil & Energy Corporation (ENEOS Holdings, Inc.)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Fujita, Goro
• Primary Examiner(s): Dunn, Drew A
• Assistant Examiner(s): GRANT, ROBERT J
• Application Number:
  US12/071,839
• Publication Number:
  US 20080203816A1
• Time in Patent Office: 2,043 Days
• Field of Search: 320/101
• US Class Current: 320/101
• CPC Class Codes: H02J 7/0063 with circuits adapted for supplying loads from the battery
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters

Abstract

Provided is a technology where a voltage capable of driving a mobile device, to which a power supply apparatus is connected, is automatically detected. The power supply apparatus, for supplying power to the device connected, includes a power supply, a voltage conversion unit which varies a voltage inputted from the power supply to a predetermined voltage and outputs the varied voltage to the device, an ammeter which measures an output current value of the power supply apparatus, and a control unit which controls the voltage varied by the voltage conversion unit. The control unit boosts the voltage outputted from the power supply in stages and detects, by detecting a change in the output current value, that the output voltage of the power supply apparatus boosted by the voltage conversion unit has reached a voltage capable of driving the device.

Claims

1. A power supply apparatus for supplying power to a device connected thereto, the apparatus comprising:

a power supply;

a voltage conversion unit which varies a voltage inputted from said power supply to output to the device a varied voltage which is an output voltage of said power supply apparatus;

an ammeter which measures an output current value of said power supply apparatus; and

a control unit which controls said voltage conversion unit to vary the output voltage of said power supply apparatus, wherein

said control unit controls the voltage conversion unit to discretely increase the output voltage of said power supply apparatus, and monitors the output current value to detect that the output voltage of said power supply apparatus has reached a voltage capable of driving the device,

after detecting that the output voltage has reached the voltage capable of driving the device, said control unit controls said voltage conversion unit to continuously decrease the output voltage of said power supply apparatus, and monitors the output current value to detect a lower limit voltage capable of driving the device, and

said control unit controls the voltage conversion unit to transmit information on said power supply apparatus to the device by periodically varying, based on a function readable by the device and associating a conversion cycle of the output voltage with the information on the power supply apparatus, the output voltage of said power supply apparatus between the voltage capable of driving the device and the lower limit voltage capable of driving the device so as to convert the information on the power supply apparatus into the conversion cycle, and by transmitting the conversion cycle to the device so that the device reads the information from the output voltage varying in accordance with the function.

2. A power supply apparatus according to claim 1, further comprising:

a secondary battery;

a charge-discharge unit which outputs electric power from said secondary battery or charges said secondary battery by use of electric power of said power supply; and

a voltmeter which measures an input voltage value to said voltage conversion unit from said secondary battery,

wherein said control unit compares the input voltage value with a predetermined voltage value,

wherein when the input voltage value is less than the predetermined voltage value, it is determined that an output power value of said power supply apparatus is insufficient to satisfy a power required by the device, and

wherein when the input voltage value is greater than the predetermined voltage value, it is determined that the output power value of said power supply apparatus is sufficient to satisfy the power required by the device, and the said secondary battery is charged by the electric power of said power supply by controlling said charge-discharge unit.

3. A power supply apparatus according to claim 2, further comprising a second voltmeter which measures an output voltage value of said power supply apparatus,

wherein said control unit compares the input voltage value in said second voltmeter with a predetermined voltage value;

and

when a transition is made from a state where the input voltage value is above the predetermined voltage value to a state where the input voltage value is below the predetermined value, said control unit calculates an output power value of said power supply apparatus by referring to the then output current value of said ammeter and the then output voltage value of said second voltmeter.

4. A power supply apparatus according to claim 2, further comprising:

a second ammeter which measures an output current value of said secondary battery; and

a second voltmeter which measures an output voltage value of said power supply apparatus,

wherein said control unit compares the output current value in said second ammeter with a predetermined current value; and

when a transition is made from a state where the output current value is below the predetermined current value to a state where the output current value is above the predetermined value, said control unit calculates the output voltage of said power supply apparatus by referring to the then output current value of said ammeter and the then output voltage value of said second voltmeter.

5. A power supply apparatus according to claim 3, wherein said control unit transmits the calculated output power value to the device in a manner such that the calculated output power is converted into a value of cycle, by which to vary the output voltage, by use of a predetermined function and the output voltage of said power supply apparatus is varied by using the value of cycle.

6. A power supply apparatus according to claim 4, wherein said control unit transmits the calculated output power value to the device in a manner such that the calculated output power is converted into a value of cycle, with which to vary the output voltage, by use of a predetermined function and the output voltage of said power supply apparatus is varied by using the value of cycle.

7. A power supply apparatus according to claim 1, wherein said power supply is a fuel cell.