Design and Implementation of High Performance Class-D Power Amplifiers by Using Feedback Compensation Techniques

• Main Authors: Ying-Jin Chiu, 邱瀛進
• Other Authors: Juhng-Perng Su
• Format: Others
• Language: en_US
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/87527521791467816581

碩士 === 國立雲林科技大學 === 電機工程系碩士班 === 93 === Conventionally, the output stage of an audio power amplifier uses Class-A or Class-AB operating in a linear transfer region to alleviate nonlinear distortion. However, it usually has power efficiency which is normally less than 70%. The CMOS Class-D power amplifier, on the other hand, operating in saturation region, has the capability of achieving 100% output efficiency in theory. Actually, there still exists power loss when the transistor is switching from “ON” to “OFF” or from “OFF” to “ON”; therefore, we can not achieve such a high efficiency. A well-designed Class-D power amplifier, however, can achieve as high as 90-95% efficiency at rated power. As a consequence, when compared with the conventional amplifiers, it is more suitable for portable and mobile applications. Unfortunately, the Class-D power amplifier has inherent nonlinear distortion problems, which is more significant than conventional amplifiers. In this thesis, we devised an output feedback compensation strategy in the loop of a Class-D power amplifier system to improve its operation performance and phase-lag problem.