Patent ID: 7307407

Claim:
A power supply apparatus comprising: a rectifier diode and a choke coil, one end of the rectifier diode and one end of the choke coil being connected to each other; a first switch element having one end connected to a connection point of the rectifier diode and the choke coil through a resonant coil; a first diode connected in parallel to the first switch element; a series circuit including a first capacitor and a second switch element, the series circuit being connected in parallel to a series circuit including the resonant coil and the rectifier diode; a second diode connected in parallel to the second switch element; parallel capacitors connected to the first switch element, the second switch element, and the rectifier diode; and a control circuit arranged to control the first switch element and the second switch element so as not to be turned on or off simultaneously, but to be turned on or off alternately; wherein the control circuit outputs a signal to control the first switch element to be turned off and the second switch element to be turned on in a standby mode; and the power supply apparatus further comprises: a switching circuit arranged to control the second switch element to be turned off in the standby mode in accordance with an input power supply operation control signal.