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Convention Paper

PWM Amplifier Control Loops with Minimum Aliasing Distortion

Authors: Neesgaard, Claus; Risbo, Lars

AES Convention 120 · Paper 6693 · May 2006

Abstract

PWM class-D audio power amplifiers contain typically a control loop filter network and a comparator producing the PWM signal. The comparator performs a sampling operation whenever it changes state. A previous paper by the author analyzed this sampling behavior from a small signal point of view. The present paper attempts to formulate a large-signal model that accounts for the non-linear effects of the sampling due to aliasing of high frequency carrier components. The model is validated using simulations and a class of loop filters is presented that obtains minimum aliasing distortion thanks to the use of quadrature sampling. Finally, measurement data are presented for real applications using the principles described.

Details

Published in
AES Convention 120
AES Convention
120
Paper number
6693
Publication date
May 6, 2006
Session subject
Signal Processing; High Resolution Audio
Affiliation
Texas Instruments Denmark A/S; Texas Instruments Inc (See document for exact affiliation information.)
Type
Convention Paper