Constant-frequency, zero-voltage-switched, clamped-mode parallel-resonant converter

The DC behavior of a constant-frequency, clamped-mode parallel-resonant converter operating above resonant frequency is characterized. The converter is shown to be able to operate with zero-voltage turn-on for all the switches from no load to full load over a wide input range. Various circuit operating modes are identified and their corresponding operating regions defined. DC characteristics for the converter design are derived. A 5 V, 50 W prototype converter operating at 104 kHz is breadboarded to show the feasibility of constant-frequency, zero-voltage-switching operation and to substantiate the analytical results. The converter is operated with zero-voltage switching from no load to full load over the entire input voltage range without any external antiparallel diodes and snubbers. The experimental results are in good agreement with the analytical predictions. An efficiency of 85% is achieved