High-frequency Full-bridge 48V DC-5V DC LLC Resonant Converter with AlGaN/GaN HEMTs

AlGaN/GaN high electron mobility transistors (HEMTs) have obvious advantages over Si devices in high-frequency resonance converters such as a DC-DC full-bridge resonant converter due to GaN HEMTs’ characteristics of low gate charge, low output capacitor and insignificant reverse recovery charge. In high power density applications, there are more advantages of the LLC converter with full bridge than the half bridge LLC system. In this article, a 250-Watt 48V-5V full bridge LLC DC-DC converter with high frequency and high power density using 100V GaN HEMTs is proposed, which achieves 96.6% peak value efficiency with the operating frequency of 1MHz. The results of this experiment are provided to validate the advantages of LLC solution using GaN HEMTs.