A zero-voltage-switching PWM flyback converter with an auxiliary resonant circuit

A novel zero-voltage-switching pulse-width-modulated (ZVS-PWM) flyback dc/dc converter with an auxiliary resonant circuit is presented in this paper. The proposed circuit topology adopts the traditional pulse-width-modulated flyback converter with an auxiliary resonant circuit. In the auxiliary resonant circuit, the resonant inductance and the resonant capacitance is operated as a resonant circuit to get a zero-voltage-switching (ZVS) in the main switch and to get a zero-current-switching (ZCS) in the auxiliary switch. The proposed ZVS-PWM flyback dc/dc converter can be operated from discontinuous conduction mode (DCM) to continuous conduction mode (CCM) and also can be used in the peak current mode control. A prototype of 150 W, 100 V to 15 V converter operated at 50 kHz is built to verify the performance of the proposed converter.