Abstract: A switching power supply includes a power switch and a mode controller that provides a mode control signal having a first level associated with a normal mode of operation of the switching power supply and a second level associated with a standby mode of operation of the switching power supply. The switching power supply further includes a feedback circuit coupled to the mode controller and a switching controller coupled to the feedback circuit. The feedback circuit has a voltage controlled current source that provides a feedback current which varies in response to the mode control signal. The switching controller switches the power switch in response to the feedback current so that in the normal mode of operation the power switch switches continuously at a predetermined frequency and in the standby mode of operation the power switch is switched on and off in bursts having a predetermined frequency.