Patent ID: 8194419

Claim:
A switching mode power supply for reducing standby power, comprising: an EMI (Electro-Magnetic Interference) filter unit connected to an input power source, for suppressing a high frequency noise component; a PFC (Power Factor Correction) unit connected to the EMI filter unit; a DC/DC unit connected to the PFC unit for converting a direct-current input voltage from the PFC unit into a direct-current output voltage of the power supply; a PFC controller connected to the PFC unit for controlling the PFC unit, the PFC controller including a feedback stage to which a link voltage at an output side of the PFC unit is fed back, and an overvoltage protection stage; a DC/DC controller connected to the DC/DC unit for controlling the DC/DC unit and generating a burst mode operation signal in a light-load or no-load condition; an error signal generation unit connected to an output terminal of the power supply for sensing the output voltage of the power supply to generate an error signal and then transmitting the error signal to the DC/DC controller; and a control unit for enabling the PFC unit to operate in a burst mode for itself by connecting the overvoltage protection stage and the feedback stage of the PFC controller, wherein when the error signal received from the error signal generation unit is smaller than a predetermined value, the DC/DC controller determines that the output terminal is in the light-load or no-load condition and generates the burst mode operation signal, upon receiving the burst mode operation signal, the DC/DC unit operates in a burst mode, and when the link voltage fed back to the feedback stage exceeds a threshold voltage of the overvoltage protection stage, the PFC controller deactivates the PFC unit.