Patent ID: 7630221

Claim:
A bridgeless power factor correction (PFC) circuit system, comprising: a bridgeless PFC circuit having: a first and a second input terminals; a first and a second output terminals; a first switch having a first terminal and a second terminal coupled to the second output terminal; a first inductor having a first terminal coupled to the first input terminal and a second terminal coupled to the first terminal of the first switch; and a second inductor having a first terminal coupled to the second input terminal; and a sensing circuit, comprising: a first auxiliary winding magnetically coupled to the first inductor and generating a first sensing signal; a second auxiliary winding magnetically coupled to the second inductor and generating a second sensing signal, wherein the first and the second sensing signals are used to generate an inductor current sensing signal and the first switch is turned on when a value of the inductor current sensing signal is a predetermined value.