A Family of High-Frequency Single-Switch DC-DC Converters With Low Switch Voltage Stress Based on Impedance Networks

This paper presents a novel family of single-switch resonant dc-dc converters with low switch voltage stress. The single-switch resonant converter which has a ground-referenced switch is advantageous for implementing the gate drive circuit and operating at several-MHz switching frequency. However, the conventional ones mostly have high voltage stress on the switch, roughly 4-5 times the input voltage. In this paper, we propose the single-switch converter topologies derived from the drain-source impedance networks consisting of two inductors and two capacitors. The switch voltage of the proposed converters is shaped into a near trapezoid by designing the resonant networks to have the desired drain-source impedance. Furthermore, a simple and specific design scheme is presented here so that the peak switch voltage is lowered to 2.2-2.5 times the input voltage while zero voltage switching is achieved. Experimental results from a 20-W GaN-based prototype operating at 10 MHz demonstrate the feasibility of the proposed converter topologies and the design method.