Patent ID: 8680823

Claim:
A power supply apparatus for converting electric energy of an input voltage to be provided to a system circuit, said power supply apparatus comprising: a front-stage power circuit for converting said input voltage into a bus voltage; a bus capacitor electrically connected with said front-stage power circuit; a standby power circuit for outputting a standby voltage; a protecting circuit electrically connected between said front-stage power circuit and said standby power circuit for flowing electric current in only one direction; an auxiliary switching circuit electrically connected between said bus capacitor and said standby power circuit; and a controlling unit electrically connected with said auxiliary switching circuit and said front-stage power circuit for controlling operations of said front-stage power circuit and said auxiliary switching circuit, wherein when said input voltage is normal but said front-stage power circuit is disabled, said auxiliary switching circuit is turned off under control of said controlling unit, so that electric energy of said input voltage is transmitted to an input terminal of said standby power circuit through said protecting circuit.