Design of High-Performance Sigma-Delta Modulators for Class-D Digital Amplifiers

• Main Authors: Wei-Tso Chen, 陳威佐
• Other Authors: Chun-Hsien Su
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/94513966852751447787

碩士 === 國立中央大學 === 電機工程研究所 === 97 === A high performance sigma-delta modulator for class-D audio amplifiers is proposed in this thesis. Class-D topology is superior to class-AB one for its higher efficiency. In addition, realizing class-D amplifier by all digital can greatly reduce audio data converter circuits, saving hardware and power consumption. However, the traditional class-D amplifier based on pulse-width modulation suffers from larger harmonic distortions and poor performance caused by limited dynamic range. This research uses sigma-delta modulation techniques to mitigate such drawback. By analyzing two different types of sigma-delta modulator topologies, a new architecture is proposed. The experimental results show that, compared to the conventional class-D sigma-delta modulators, the proposed architecture can improve total harmonic distortions about 10% and can operate with a modulation index of 100% maximum input range, with same hardware complexity.