Efficiency improvement in adjustable deadtime of LLC resonant converters

This paper presents an analysis of high efficiency feasibility at wide load in LLC-SRC Resonant Converter. LLC-SRC Resonant Converter could be achieved zero voltage switching turn on by resonant scheme. A fixed deadtime must be larger than the discharge time for the effective drain-source capacitance of Mosfet during switching off. Ensure that parasitic capacitance of the half bridge including Mosfet´s capacitance has been discharged before switching turn on. But conduction loss is appeared Transformer and Power Mosfet at heavy load. Because resonant current is higher than enough to obtain discharge capability by proper magnetic inductance. Especially, the resonant tank current flows through into the body diode of Mosfet at heavy load. In order to achieve high efficiency of LLC-SRC resonant converters. An adjustable deadtime could be feasibly to improve efficiency from light load to heavy load.