Patent ID: 8358517

Claim:
A switching power conversion circuit for receiving an input voltage and generating an output voltage to a system circuit, said switching power conversion circuit comprising: a power circuit comprising a first switch circuit, wherein said input voltage is converted into said output voltage and a first auxiliary voltage by alternately conducting and shutting off said first switching circuit; a feedback circuit connected to said power circuit for generating a feedback signal according to a power-status signal issued by said system circuit and said output voltage; a control circuit connected to said first switching circuit and said feedback circuit, wherein said first switching circuit is conducted or shut off according to said feedback signal under control of said control circuit, so that said input voltage is converted into said output voltage and said first auxiliary voltage by said power circuit; and an initiation circuit connected to said system circuit and said control circuit, wherein an initiation voltage is issued by said initiation circuit according to said power-status signal, wherein if said power-status signal is in an off status, a ratio of said feedback signal to said output voltage is equal to a first feedback ratio and the magnitude of said first auxiliary voltage is lower than a normal operating voltage value, so that said control circuit is disabled.