A new constant frequency zero voltage switching buck quasi-resonant converter

A new buck zero-voltage-switching quasi-resonant power converter operating at constant switching frequency is discussed. Its output voltage is regulated by controlling the freewheeling period of the resonant inductor. In addition to better controllability, it possesses the advantages of PWM and frequency-modulated power converters. The principle of operation, state-plane plots, steady-state characteristics, design procedure and simulation of this buck constant frequency zero-voltage-switching quasi-resonant power converter (CF-ZVS-QRC) are presented.