Sigma-Delta Modulation Class-D Dgital Power Amplifier

• Main Authors: Liu-Pane-you, 劉邦祐
• Other Authors: Guan-Chyun Hsieh
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/89847845166835096545

碩士 === 國立臺灣科技大學 === 電子工程系 === 93 === A Class D power amplifier by sigma-delta modulation (SDM) is proposed. Cycle-by-cycle control loop is adopted in converting the analog signal into a digital one. Except a constant pulse time to detect the sampled input signal level, a duty period is generated by a discharging/charging rate generated in SDM and its length is dependent on the detected input level and is a multiple of the constant sampling pulse time. Signal process and system model for converting the analog signal into digital one through the SDM modulator is explored. A prototype of 100W class D power amplifier is examined for assessing the theoretical investigation and practicality. The power efficiency is over 87%. The total harmonic distortion (THD) measured without EMI filter is less than 4%.