LLC resonant converter for 48 V to 0.9 V VRM

48 V to 0.9 V VRM using LLC resonant converter is presented. ZVS is realized for switches and the converter can operate at higher frequency. How to reduce primary current amplitude by reducing power factor angle is explored. The effect of secondary leakage inductance is studied and FEA method is used to find the optimal transformer winding con figuration. The resonant inductor can be integrated with transformer primary leakage inductance, which reduces the total magnetic component counts. A prototype of 48 V to 0.9 V/50 A VRM is built to verify the result.