Improvement in Voltage Conversion Ratio of Ultrahigh Step-Down Converter

Abstract

A modified step-down converter is presented herein, which is mainly based on one coupled inductor and several energy-transferring capacitors to improve the voltage conversion ratio as well as to reduce the switch voltage stress. In addition, the portion of the leakage inductance energy can be recycled to the input via the active clamp circuit during the turn-off period and the switches have zero-voltage switching (ZVS) during the turn-on transient. In this paper, the basic operating principles of the proposed converter are firstly described and analyzed, and its effectiveness is finally demonstrated by experiment based on a prototype with input voltage of 60 V, output voltage of 3.3 V and rated output power of 33 W.