Spread spectrum techniques for Class-D audio amplifiers to reduce EMI

Mario Auer*, Timucin David Karaca

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


For battery powered portable devices it is required to have circuits that combine high efficiency with a small footprint. In the case of Class-D amplifiers the high efficiency can be achieved by applying pulse-width modulation (PWM) to generate the desired output signal. Classical PWM requires an output filter to suppress the idle current. In order to avoid this filter a different modulation scheme is used, which however introduces a larger amount of electromagnetic emissions. Therefore spread-spectrum techniques are applied to distribute the emissions over a wider frequency range. In this article methods are discussed that allow the use of spread-spectrum modulation without introducing audible artifacts due to the modulation.
Translated title of the contributionSpread-Spectrum-Methoden für Klasse-D-Verstärker zur Reduktion von EMI
Original languageEnglish
Pages (from-to)43-47
JournalElektrotechnik und Informationstechnik
Issue number1
Publication statusPublished - Feb 2016


  • Class-D audio amplifier
  • spread spectrum modulation
  • EMC
  • EMI

Fields of Expertise

  • Information, Communication & Computing

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