Comparison of Power Supply Pumping of Switch-Mode Audio Power Amplifiers with Resistive Loads and Loudspeakers as Loads

Arnold Knott, Lars Press Petersen

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Abstract

Power supply pumping is generated by switch-mode audio power amplifiers in half-bridge configuration, when they are driving energy back into their source. This leads in most designs to a rising rail voltage and can be destructive for either the decoupling capacitors, the rectifier diodes in the power supply or the power stage of the amplifier. Therefore precautions are taken by the amplifier and power supply designer to avoid those effects. Existing power supply pumping models are based on an ohmic load attached to the amplifier. This paper shows the analytical derivation of the resulting waveforms and extends the model to loudspeaker loads. Measurements verify, that the amount of supply pumping is reduced by a factor of 4 when comparing the nominal resistive load to a loudspeaker. A simplified and more accurate model is proposed and the influence of supply pumping on the audio performance is proven to be marginal.
Original languageEnglish
Title of host publication134th Audio Engineering Society Convention 2013
PublisherAudio Engineering Society
Publication date2013
Pages 302-311
ISBN (Print)9781627485715
Publication statusPublished - 2013
EventAES 134 th Convention - Rome, Italy
Duration: 4 May 20137 May 2013

Conference

ConferenceAES 134 th Convention
CountryItaly
CityRome
Period04/05/201307/05/2013

Bibliographical note

Convention Paper 8838

Keywords

  • Audio equipment
  • Loudspeakers
  • Electric rectifiers
  • Accurate modeling
  • Audio power amplifier
  • Decoupling capacitor
  • Pumping model
  • Rail voltage
  • Rectifier diodes
  • Resistive loads

Cite this

Knott, A., & Petersen, L. P. (2013). Comparison of Power Supply Pumping of Switch-Mode Audio Power Amplifiers with Resistive Loads and Loudspeakers as Loads. In 134th Audio Engineering Society Convention 2013 (pp. 302-311). Audio Engineering Society.