Patent ID: 8199541

Claim:
A bridgeless PFC power converter comprising: a first inductor, coupled from a first input-terminal to a first transistor; a second inductor, coupled from a second input-terminal to a second transistor; a first diode, coupled from the first transistor to an output capacitor; a second diode, coupled from the second transistor to the output capacitor, in which the first transistor, the second transistor and the output capacitor are further coupled to a ground terminal; a first capacitor, coupled from the first input-terminal to the ground terminal through a third transistor; a second capacitor, coupled from the second input-terminal to the ground terminal through a fourth transistor; and a control circuit, coupled to the output capacitor to receive a feedback signal, the control circuit coupled to the first input-terminal and the second-input terminal to receive a first-input signal and a second-input signal, the control circuit coupled to the first transistor and the second transistor for detecting a first-current signal and a second-current signal; wherein the control circuit generates a first-switching signal and a second-switching signal to control the first transistor and the second transistor in response to the feedback signal, the first-input signal, the second-input signal, the first-current signal and the second-current signal, the second-switching signal will turn on the second transistor when the first-switching signal switches the first transistor, the first-switching signal will turn on the first transistor when the second-switching signal switches the second transistor; the control circuit further generates a light-load signal to turn off the third transistor and the fourth transistor during a light-load of the PFC power converter.