Patent ID: 8013581

Claim:
A power supply circuit configured for supplying power for a load, comprising: a main power supply configured for converting a received voltage into a required direct current voltage; a microprocessor; a stand-by control circuit configured for controlling the main power supply, the stand-by control circuit comprising a switch, a trigger, a transistor, an optical coupler, a reverser, a first output terminal and a second output terminal, the switch comprising a first terminal and a second terminal, the first terminal of the switch connected between the second output terminal and the trigger, the second terminal of the switch connected to ground, a control electrode of the transistor connected to the trigger, a first terminal of the transistor connected to the trigger, a second terminal of the transistor connected to the optical coupler, the first output terminal of the stand-by control circuit connected to the optical coupler via the reverser, the reverser connected to the main power supply, the trigger and the control electrode of the transistor further connected to the microprocessor; an energy storage circuit comprising an output terminal connected to the first terminal of the transistor, and the energy storage circuit supplying power for the trigger and the transistor of the stand-by control circuit via the output terminal; wherein in response to when the load stops operating, the microprocessor outputs a switch-off signal to the control electrode of the stand-by control circuit in order to switch off the transistor, the reverser of the stand-by control circuit correspondingly outputs a first control signal to turn off the main power supply; and in response to when the load starts to operate, the trigger outputs a switch-on control signal to the control electrode of the stand-by control circuit in order to switch on the transistor, the reverser of the stand-by control circuit correspondingly outputs a second control signal to turn on the main power supply, and the main power supply charges the energy storage circuit.