A New Family of Zero Voltage Transition PWM Converters

In this paper a new auxiliary circuit is introduced for buck, buck-boost, forward and flyback converters. This auxiliary circuit provides zero oltage switching condition for the main switch and diode while providing zero current switching condition for the auxiliary switch and diodes. The proposed ZVT PWM buck converter is analyzed and various converter operating modes are presented. A very simple design method for auxiliary circuit is discussed. Experimental results of ZVT buck converter from a 140 W laboratory prototype switching at 120 KHz are presented. Also the experimental results of a ZVT flyback converter are shown.