基于Σ-Δ调制和DirectFET器件的D类功放设计  

Design of Class D Power Amplifier Based on Sigma-Delta Modulation and DirectFET Devices

作　　者：欧阳宏志[1] OUYANG Hongzhi(College of Electrical Engineering,University of South China,Hengyang,Hunan 421001,China)

机构地区：[1]南华大学电气工程学院

出　　处：《湖南城市学院学报（自然科学版）》2020年第1期65-69,共5页Journal of Hunan City University:Natural Science

基　　金：湖南省教育厅教育科学“十三五”规划课题(XJK17BGD067);南华大学校级教改项目(2017XJG-ZD05)

摘　　要：音频功率放大器是电子设备的重要组成部分,其输出功率、效率和非线性失真要求越来越高.为解决D类功放效率和失真之间的矛盾,引入Σ-Δ调制减小非线性失真,使用DirectFET开关管提高功放效率,并设计制作了一台D类功放机.文章对Σ-Δ调制原理进行了详细地阐述,并设计了前置放大电路、调制电路、功率变换电路和滤波电路等,仿真结果达到预期要求.测试结果显示:该机器在4Ω负载上输出功率达100W,总谐波失真小于1%,效率最高可达94%.相比PWM调制和其它常规封装开关管设计的装置,失真和效率均有一定改善.Audio power amplifier is an important part of electronic equipment, and the requirements of its output power, efficiency and nonlinear distortion are getting higher and higher. In order to solve the contradiction between the efficiency and the distortion in class D power amplifier, Σ-Δ modulation is introduced to reduce the nonlinear distortion, DirectFET switching device is used to improve the efficiency, and a class D power amplifier is designed and manufactured. The principle of the Σ-Δ modulation is elaborated, and preamplifier circuit, a modulation circuit, power conversion circuit, and filter circuit are designed. The simulation results meet expected requirements. Test results show that the machine has an output power of 100 W on a 4 Ω load, a total harmonic distortion(THD) of less than 1%, and an efficiency of up to 94%. Compared with PWM modulation and other devices, the distortion and the efficiency are improved.

关 键 词：Σ-Δ调制 D类功放 MOS管 效率 总谐波失真 

分 类 号：TN722.5[电子电信—电路与系统]