A class B switch-mode assisted linear amplifier

Walker, G. R. (2003) A class B switch-mode assisted linear amplifier. Ieee Transactions on Power Electronics, 18 6: 1278-1285. doi:10.1109/TPEL.2003.818825

Author Walker, G. R.
Title A class B switch-mode assisted linear amplifier
Journal name Ieee Transactions on Power Electronics   Check publisher's open access policy
ISSN 0885-8993
Publication date 2003
Sub-type Article (original research)
DOI 10.1109/TPEL.2003.818825
Volume 18
Issue 6
Start page 1278
End page 1285
Total pages 8
Editor J. Van Wyk
Place of publication Piscataway, NJ
Publisher The Institute of Electrical and Electronics Engineers
Collection year 2003
Language eng
Subject C1
290901 Electrical Engineering
660402 Residential and commercial
Abstract A switch-mode assisted linear amplifier (SMALA) combining a linear (Class B) and a switch-mode (Class D) amplifier is presented. The usual single hysteretic controlled half-bridge current dumping stage is replaced by two parallel buck converter stages, in a parallel voltage controlled topology. These operate independently: one buck converter sources current to assist the upper Class B output device, and a complementary converter sinks current to assist the lower device. This topology lends itself to a novel control approach of a dead-band at low power levels where neither class D amplifier assists, allowing the class B amplifier to supply the load without interference, ensuring high fidelity. A 20 W implementation demonstrates 85% efficiency, with distortion below 0.08% measured across the full audio bandwidth at 15 W. The class D amplifier begins assisting at 2 W, and below this value, the distortion was below 0.03%. Complete circuitry is given, showing the simplicity of the additional class D amplifier and its corresponding control circuitry.
Keyword Engineering, Electrical & Electronic
Class B Amplifier
Class D Amplifier
Half-bridge Current
Hysteretic Controlled
Parallel Buck Converter
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2004 Higher Education Research Data Collection
School of Information Technology and Electrical Engineering Publications
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Citation counts: TR Web of Science Citation Count  Cited 27 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 36 times in Scopus Article | Citations
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Created: Wed, 15 Aug 2007, 01:49:58 EST