Patent ID: 8050061

Claim:
A control circuit for a switching power supply (SPS), the control circuit comprising: a power input interface to receive an external alternating current (AC) power signal; a power output interface to output the AC power signal from the power input interface; a relay comprising a relay switch, the relay switch connected between the power input interface and the power output interface; a relay driving circuit to drive the relay switch to be turned on or turned off; a microprocessor to control the relay driving circuit and connected to a computer motherboard; and an alternating current/directing current (AC/DC) converter to receive the AC power signal from the power input interface, and transform the AC power signal into a direct current (DC) power signal to supply power to the relay, the relay driving circuit, and the microprocessor; wherein the microprocessor sends a first control signal to control the relay driving circuit to turn on the relay switch to connect the power input interface to the power output interface in response to the microprocessor receiving a power-on signal from the computer motherboard; and wherein the microprocessor sends a second control signal to control the relay driving circuit to turn off the relay switch to cut off connection between the power input interface and the power output interface in response to the microprocessor receiving a power-off signal from the computer motherboard.