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 2003-01-01
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
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
Dead-band
Distortion
Half-bridge Current
Hysteretic Controlled
Parallel Buck Converter
Smala
Topology
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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Created: Wed, 15 Aug 2007, 11:49:58 EST