A Low Power Class-AB Audio Power Amplifier with Dynamic Transconductance Compensation in 55 nm CMOS Process

Fang Tang, Shiping Li, Bo Wang, Amine Bermak, Xichuan Zhou, Shengdong Hu

Research output: Contribution to journalArticle

1 Citation (Scopus)


This paper presents a Class-AB audio power amplifier with state-of-the-art power efficiency and performance. In this work, the second stage transconductance of the three-stage power amplifier can be dynamically compensated, in order to automatically adjust the amplifier pole according to the operating condition of the output stage. Working with a current sensing module, the proposed dynamic transconductance compensation scheme is more power-efficient to allocate the frequency of non-dominant-pole under a specified stability requirement. A prototype chip is designed and fabricated using 55 nm CMOS process. The measured static current consumption of the core circuit is 0.35 mA with a 1.8 V supply voltage. -85 dB THD+N, 106 dB signal dynamic range and 55 mW output power are verified in silicon under a wide range of load capacitance from 5 pF to 20 nF. Measurement result shows the proposed transconductance compensation technique is effective in both constant voltage supply mode and dynamic supply (Class-G) mode.

Original languageEnglish
Article number7546880
Pages (from-to)1360-1369
Number of pages10
JournalIEEE Transactions on Circuits and Systems I: Regular Papers
Issue number9
Publication statusPublished - 1 Sep 2016



  • Audio power amplifier
  • class-AB
  • CMOS integrated circuit
  • low power

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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