A second-order class-D audio amplifier

Cox, Stephen M. and Tan, M.T. and Yu, J. (2011) A second-order class-D audio amplifier. SIAM Journal on Applied Mathematics, 71 (1). pp. 270-287. ISSN 0036-1399

[img] PDF - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
Download (329kB)

Abstract

Class-D audio amplifiers are particularly efficient, and this efficiency has led to their ubiquity in a wide range of modern electronic appliances. Their output takes the form of a high-frequency square wave whose duty cycle (ratio of on-time to off-time) is modulated at low frequency according to the audio signal. A mathematical model is developed here for a second-order class-D amplifier design (i.e., containing one second-order integrator) with negative feedback. We derive exact expressions for the dominant distortion terms, corresponding to a general audio input signal, and confirm these predictions with simulations. We also show how the observed phenomenon of “pulse skipping” arises from an instability of the analytical solution upon which the distortion calculations are based, and we provide predictions of the circumstances under which pulse skipping will take place, based on a stability analysis. These predictions are confirmed by simulations.

Item Type: Article
Additional Information: (c) SIAM
Schools/Departments: University of Nottingham UK Campus > Faculty of Science > School of Mathematical Sciences
Identification Number: https://doi.org/10.1137/100788367
Depositing User: Cox, Stephen
Date Deposited: 09 Feb 2013 17:06
Last Modified: 14 Sep 2016 03:25
URI: http://eprints.nottingham.ac.uk/id/eprint/1888

Actions (Archive Staff Only)

Edit View Edit View