Dual Voltage Flyback Topology Operation With Efficiency Enhancers at Dual Voltage Mains

Abstract

This article introduces a Dual Voltage Flyback converter which overcomes the low efficiency of the conventional Flyback converter over universal mains voltages. The topology comprises of reconfigurable primary power loops enabled by additional state switches. This combination allows the converter to run in parallel or series modes, enhancing the performance at both 230Vac high line and 115Vac low line mains. It reduces the voltage rating of devices, supports two operating points that operate in boundary conduction mode under fixed frequency and improves the utilization of the devices. A 75W, 90Vac-265Vac to 24Vdc converter has been designed and tested. The converter is compatible with efficiency enhancement solutions such as synchronous rectifier and quasi-resonant control presented in this paper. The experimental results show that the proposed converter has a significant performance improvement at universal mains without any additional efficiency enhancer and considerable performance improvement when using synchronous rectifier compared to a conventional Flyback converter. However, solutions that reduce high voltage stress are less beneficial to the suggested topology.