Analysis and Implementation of a Single-Stage Transformer-Less Converter With High Step-Down Voltage Gain for Voltage Regulator Modules

Abstract

A novel transformer-less topology with high step-down voltage gain is proposed for low-voltage high-current point-of-load voltage regulator modules (VRMs). The proposed topology consists of three capacitors, two inductors, three active switches, and two synchronous rectifiers. It triples the effective duty-ratio and lowers the voltage stresses across active switches compared with conventional buck topologies. Converters based on the topology have a potential benefit of achieving high power density and can be capable of delivering high current to the output by two interleaving phases. Small inductance and capacitance are only needed by using interleaving technology, which results in very fast dynamic response to large load changes. A 60 W, 48-1.8 V prototype is built to verify the performance of the proposed topology.