IEEE Workshop on Wide Bandgap Power Devices and Applications in Asia (WiPDA Asia 2018)

239 / 2017-11-22 15:44:12

Design of a 20MHz eGaN FET-Based Isolated Class E DC-DC Converter

Class E dc-dc converter, On-Off control, parameters design, resonant converter, isolated converter

Plenary track > Hard-switched and soft-switched applications

Isolated Class E DC-DC converter is widely used in multi-MHz switching frequency applications since it could easily achieve zero voltage switching (ZVS) and has simple topology. However the design of its circuit parameters is difficult due to its complex resonace operation. This paper proposes a direct design method for isolated Class E DC-DC converter with On-Off control and the circuit is shown in Fig. 1. The method does not require trial and error or complex numerical calculation.
In the proposed design approach, the rectifier network in the Class E DC-DC converter is firstly equivalent to a pure resistor Rrec, which could help simplify the design of the parameters. Afterwards, three constraints are considered, including the realization of the zero voltage switching, the demand of rated output capacity and the sinusoidal degree of the resonant current. In addition, the duty cycle of the power switch is also optimized selected to achieve higher efficiency. According to the conditions above, the parameters of Class E DC-DC converter can be obtained analytically.
A 20 MHz 12 V/24 W prototype converter is implemented using enhancement-mode GaN FET and experimental results validate the effectiveness of the proposed design approach.