Analysis and Design of LLC Resonant Converter with Integrated Transformer

LLC resonant converter has a lot of advantages over the conventional series resonant converter and parallel resonant converter; narrow frequency variation over wide load and input variation, Zero Voltage Switching (ZVS) for entire load range and integration of magnetic components. This paper presents analysis and design consideration for half-bridge LLC resonant converter with integrated transformer. Using the fundamental approximation, the gain equation is obtained, where the leakage inductance in the transformer secondary side is also considered. Based on the gain equation, the practical design procedure is investigated to optimize the resonant network for a given input/ output specifications. The analysis and design procedure are verified through an experimental prototype converter.