Switching circuit of power converter having voltage-clipping device to improve efficiency

摘要

A switching circuit for power converters is presented. It includes a voltage-clipping device, a resistive device, a first transistor and a second transistor. The voltage-clipping device is coupled to an input voltage. The first transistor is connected in series with the voltage-clipping device for switching the input voltage. The second transistor is coupled to control the first transistor and the voltage-clipping device in response to a control signal. The resistive device provides a bias voltage to turn on the voltage-clipping device and the first transistor when the second transistor is turned off. Once the second transistor is turned on, the first transistor is turned off and the voltage-clipping device is negatively biased. The voltage-clipping device is developed to clamp a maximum voltage for the first transistor.