Adaptive Soft Switching Asymmetrical Half-Bridge Flyback Converter With Wider Voltage Range

Abstract

The asymmetrical half-bridge flyback (AHB-Flyback) topology employing soft switching techniques has gained widespread use due to its ability to achieve high efficiency while accommodating a wide voltage range in rapidly evolving portable electronics. Zero-voltage switching (ZVS) is a key technique for implementing soft switching in AHB-Flyback converters. However, the practical implementation of ZVS is often hindered by the variability of off-chip component parameters and the broad input and output voltage ranges required by AHB-Flyback converters. This article introduces a novel adaptive soft switching strategy with high regulation accuracy for AHB-Flyback converters. This approach addresses the impacts of parameter variations and fluctuations in the sampling value of input and output voltages, thereby increasing efficiency. A controller integrated circuit (IC) has been fabricated using the TSMC $0.5-\mu$ m BCD mixed-signal process and verified with a prototype experimental test board rated at 60 W/20 V, achieving a maximum efficiency of 94.09%.