A 94% efficiency near-constant frequency self-oscillating class-D audio amplifier with voltage control resistor

Shao Siang Ng, Kuei Liang Lin, Ke-Horng Chen, Yu Wen Chen

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations

Abstract

A self-oscillating constant frequency class-D audio amplifier with voltage control resistor (VCR) technique is proposed for system-on-a-chip (SoC) applications. The VCR control circuit is used to ensure stable switching frequency over a wide range of the modulation index. The proposed method also improves the THD performance at high output power condition. The proposed self-oscillating class-D amplifier can have extremely good performance since the carrier distortion is avoided and the intrinsic harmonic can be attenuated by the second-order loop filter. The VCR control can dynamically adjust the switching frequency according to distinct modulation index. In addition, stable frequency operation can reduce the switching frequency at low output amplitude to improve power efficiency. Experimental results demonstrate that the proposed class-D amplifier can delivers 1.4W to the 8 load with a 5V supply. The power efficiency is achieved over 95% and the output THD can be smaller than 0.001%.

Original languageEnglish
Title of host publication2013 IEEE International Symposium on Circuits and Systems, ISCAS 2013
Pages602-605
Number of pages4
DOIs
StatePublished - 9 Sep 2013
Event2013 IEEE International Symposium on Circuits and Systems, ISCAS 2013 - Beijing, China
Duration: 19 May 201323 May 2013

Publication series

NameProceedings - IEEE International Symposium on Circuits and Systems
ISSN (Print)0271-4310

Conference

Conference2013 IEEE International Symposium on Circuits and Systems, ISCAS 2013
CountryChina
CityBeijing
Period19/05/1323/05/13

Keywords

  • class-D
  • frequency stable technique
  • self-oscillating audio amplifier
  • SoC system

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  • Cite this

    Ng, S. S., Lin, K. L., Chen, K-H., & Chen, Y. W. (2013). A 94% efficiency near-constant frequency self-oscillating class-D audio amplifier with voltage control resistor. In 2013 IEEE International Symposium on Circuits and Systems, ISCAS 2013 (pp. 602-605). [6571914] (Proceedings - IEEE International Symposium on Circuits and Systems). https://doi.org/10.1109/ISCAS.2013.6571914