Analog Integrated Circuits and Signal Processing

, Volume 74, Issue 2, pp 439–451 | Cite as

Sliding mode audio class-D amplifier for portable devices

  • Gael Pillonnet
  • Remy Cellier
  • Angelo Nagari
  • Philippe Lombard
  • Nacer Abouchi


Audio class-D amplifiers are widely used in industrial and consumer portable electronic devices, such as mobile phones, thanks to their high efficiency. However, these amplifiers have a limited linearity due to their switching behavior and also a limited control bandwidth. To overcome these major drawbacks, this paper introduces a self-oscillating control technique based on the sliding mode theory which combines a large control bandwidth and a spread spectrum technique. A high power supply rejection, which is a crucial parameter in modules directly connected to a noisy battery, has also been achieved by introducing a variable hysteresis window. Theoretical analysis, behavioral and electrical simulations are discussed in detail in this paper. An integrated circuit using 0.13 μm CMOS process has been realized focused on mobile phone applications (0.8 W, 3.6 V and 8 Ω). The audio amplifier achieves 97 dB(A) signal-to-noise ratio, 0.02 % harmonic distortion and up to 80 dB of power supply rejection. The die area is smaller than 0.4 mm2 while keeping more than 90 % efficiency at 1 W.


Switching audio amplifier Class D Self-oscillating Sliding mode control 


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Copyright information

© Springer Science+Business Media New York 2012

Authors and Affiliations

  • Gael Pillonnet
    • 1
  • Remy Cellier
    • 1
  • Angelo Nagari
    • 2
  • Philippe Lombard
    • 1
  • Nacer Abouchi
    • 1
  1. 1.CPE Department, Institute of Nanotechnology, University of LyonVilleurbanneFrance
  2. 2.ST Ericsson, Advanced IP DivisionGrenobleFrance

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