Analysis and design of Class-E power amplifiers at any duty ratio in frequency domain

作者:Yang, Tianliang; Liang, Junrui; Zhao, Chunyu; Chen, Dayue*
来源:Analog Integrated Circuits and Signal Processing, 2011, 67(2): 149-156.
DOI:10.1007/s10470-010-9568-3

摘要

This paper presents a design method for Class-E power amplifiers based on the analysis of the load impedance in the frequency domain. The analytical expressions of the design parameters are derived as functions of the duty ratio D and angular frequency omega(0) of the gate driven voltage of the switch. According to the analysis, for an optimal Class-E amplifier that meets both the zero-voltage switching (ZVS) and the zero-derivative switching (ZDS) conditions, the increase of the duty ratio D results in the decrease of the DC input resistance, and this consequently increases the input power and decreases the total efficiency. Two design procedures for different design purposes are discussed under three cases with different duty ratios, i.e. D = 0.25, 0.5 and 0.75. The simulation and experimental results of these cases agree well with the theoretical ones.