Analysis and Design of Class-E Amplifier with Nonlinear Output Capacitance Model Using Sigmoid Function for GaN HEMT

Abstract

High-switching frequency power converters are used in wireless power transmission and material processing. Soft-switching technique is crucial to reduce switching loss in high-frequency operation, e.g. ISM(Industrial Scientific and Medical) bands such as 13.56 MHz and 27.12MHz. Recently, GaN power devices are expected to realize high-frequency operation of a power converter. The voltage dependency of the output capacitance in GaN power device exhibits highly nonlinear characteristics, making the analysis and design of the power converter difficult. This paper proposes to apply the sigmoid function to model the voltage dependency of the output capacitance in a GaN power device. The design of the class-E amplifier using the proposed model is presented. Circuit simulations with device model and experiments demonstrate class-E switching operation.