Design of GaN transistor-based class E DC-DC converter with resonant rectifier circuit

This paper proposes a novel design of class E dc-dc converter with a resonant rectifier circuit. Class E converter is advantageous in several-MHz switching since it achieves zero voltage switching (ZVS) and has the single ground-referenced switch. In this paper, the resonant rectifier is used to construct a dc-dc converter in conjunction with the class E inverter instead of the conventional rectifiers such as a half-wave rectifier and a full-wave bridge rectifier. The main benefit of the resonant rectifier is that the rectifier diode turns on and off at low dv/dt, thereby reducing switching loss and noise mainly attributed to the parasitic inductance and capacitance. Here we focus on the analysis and design of the resonant rectifier and analytically find the condition that the rectifier circuit can be seen as a resistor. Compared to other studies, the proposed design of the rectifier requires no large filter inductor. Also, its resonant frequency differs from the fundamental frequency, allowing the rectifier to be resistive. A 6.78-MHz prototype converter is implemented by using an enhancement-mode GaN FET, and experimental results validate the proposed design scheme.