High efficiency DC-DC converter

Abstract

A family of power converter topologies employing two complementary switches in the primary and two MOSFET synchronous rectifiers in the secondary is presented. The use of two complementary switches in the primary leads to soft transitions across the switching elements, and the complementary square waveforms reflected in the secondary offers a simple and efficient driving waveform for the synchronous rectifiers. Employing one of these topological configurations, a very high efficiency and high power density 150 W converter was implemented. The power converter operates from an input voltage of 35 V to 72 V providing 5 V at 30 A, with an efficiency above 90% at full load. High efficiency combined with the use of a full integrated multilayer PCB magnetic technology has allowed a power density of 51 W/in/sup 3/.< >