Class D Audio Amplifiers

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Introduction

A Class D amplifier uses the active output devices as switches, at a frequency in excess of the bandwidth of the amplifier. This allow a very high efficiency to be achieved. However, traditionally, this has been at the expense of quality. Recently, there has been a lot of interest in this technique, and I did a final year project at Coventry University on one possible solution to this problem, by creating a composite amplifier. The result was a quality amplifier, delivering over 20W into a 4.4 ohm load. The abstract of the final report for this work is available here, and I may be able to supply more details against a specific request. However, such requests must be approved by Coventry University.

This report has had several people enquiring about it, and so I include a list of them here. It may be that they can assist researchers in this area with details of their own work.

email address Organisation Contact date Notes
Fernando California 07 Oct 2000  
Gerard Van Woggelum Holland 21 Sep 2000  
Håkan Svensson www.svep.se . 15 Sep 2000  
Krissanapong Nandhasri Mahanakorn univ Bangkok Thailand. 05 Aug 2000  
Paul Morrow Analog Devices 04 Aug 2000  
karsten madsen" km_cad@yahoo.com. cad audio dk 08 Jul 2000  
Eddy Bergers Summit Engineering nv tel +32 11 69.42.59 fax +32 11 69.45.92 06 Jul 2000 Actually there was a patent by Peter Garde I believe in 85 describing the technique (Vienna was not first).
CARLOS ALBERTO JACOBO PEDRAZA Instituto Tecnologico de morelia, Mexico; 04 Jul 2000  
Tong Lin cornell university 04 Jul 2000  
Christian Österlind University of Karlskrona/Ronneby, Sweden. 29 Jun 2000  
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Copyright (c) 2000 David Lee.
Last revised: October 14, 2000.

Hot List

During this work I discovered several manufacturers and articles who had information on the Internet, so here are the links to them.

of 3rd Sept, 2001, featured an article on digital audio, and gave additional web sites, which I have added.