Fundamental Analysis for LLC Resonant DC-DC Converter with a Reverse Multi-resonant LC Filter on Characteristics of DC Voltage Conversion Ratio

Abstract

This paper presents a new LLC multi-resonant DC-DC converter with a reverse resonant LC filte.The proposed DC-DC convert ercircuit can improve the sensitivity of voltage conversion ratio in the step-down area,and then achieve the high performance on output voltage and power regulation by PFM under soft switching conditions.The proposed DC-DC converter can achieve a high frequency Zero Voltage and Zero Current Softswitching (ZVZCS) turn-on and Zero Voltage Soft switching (ZVS) turn-off operations.The theoretical analysis and simulation results of the proposed DC-DC converter are described.Then,the characteristics on the voltage conversion ratio and output power reguration of the conventional LLC resonant DC-DC converter and the proposed DC-DC converter are compared,and the advantageous features in the proposed DC-DC converter are clearly demonstrated.