Patent ID: 8484491

Claim:
A power supply apparatus comprising: a converter circuit that converts an alternating current output from an AC power supply to a direct current; a battery that is charged by the direct current output from the converter circuit; a first power supply circuit that outputs a first voltage that is within an allowable range of a load voltage of a load circuit from either one of the converter circuit and the battery to a load circuit; a second power supply circuit that outputs either one of a second voltage that is within the allowable range and a third voltage that is lower than the first voltage from either one of the converter circuit and the battery to the load circuit; and a power supply control unit that causes the first power supply circuit to output the first voltage and causes the second power supply circuit to output the third voltage, when the alternating current is output from the AC power supply, and the power supply control unit causing the second power supply circuit to output the second voltage and causes the first power supply circuit to stop outputting the first voltage, when the AC power supply is stopped, and wherein the outputting by the second power supply circuit outputs a different voltage depending on a state of the power supply apparatus being one of a standby state and a start state, the state chosen in accordance with an instruction from the power supply control unit and where the power supply apparatus outputs, while in the standby state, a voltage that is lower than the voltage output from the first power supply circuit.