EMI reduction in Class-D amplifiers by actively reducing PWM ripple

Christiaan Egidius Lokin; Ronan A.R. van der Zee; Daniel  Schinkel; Bram  Nauta

doi:10.1109/TCSI.2019.2952543

EMI reduction in Class-D amplifiers by actively reducing PWM ripple

Christiaan Egidius Lokin^*, Ronan A.R. van der Zee, Daniel Schinkel, Bram Nauta

^*Corresponding author for this work

Research output: Contribution to journal › Article › Academic › peer-review

8 Citations (Scopus)

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Abstract

Class-D amplifiers switch high voltages and currents at high frequencies and hence produce electromagnetic interference (EMI). This work presents a technique to reduce the high frequency ripple, which is still present after the output filter. A Class-A ripple reduction amplifier is put in parallel to the output of the Class-D amplifier, each having their own feedback loop with digital filters. High ripple reduction loop gain is achieved at the PWM frequency by using a resonator as digital loop filter. Dissipation in the Class-A amplifier is reduced by using a low common-mode signaling technique. Common-mode and differential-mode switching components at the PWM frequency are reduced by 27 dB and 18 dB respectively. Total system efficiency is 79% at 40 W output power.

Original language	English
Article number	8913516
Pages (from-to)	765-773
Number of pages	9
Journal	IEEE transactions on circuits and systems I: regular papers
Volume	67
Issue number	3
Early online date	26 Nov 2019
DOIs	https://doi.org/10.1109/TCSI.2019.2952543
Publication status	Published - 1 Mar 2020

Keywords

Audio power amplifier
class-D amplifier
ripple reduction
delta-sigma analog to digital converter
electromatic interference (EMI)
BD modulation

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10.1109/TCSI.2019.2952543

Paper Lokin TCSI nov 2019Accepted author version, 1.52 MB

Cite this

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title = "EMI reduction in Class-D amplifiers by actively reducing PWM ripple",

abstract = "Class-D amplifiers switch high voltages and currents at high frequencies and hence produce electromagnetic interference (EMI). This work presents a technique to reduce the high frequency ripple, which is still present after the output filter. A Class-A ripple reduction amplifier is put in parallel to the output of the Class-D amplifier, each having their own feedback loop with digital filters. High ripple reduction loop gain is achieved at the PWM frequency by using a resonator as digital loop filter. Dissipation in the Class-A amplifier is reduced by using a low common-mode signaling technique. Common-mode and differential-mode switching components at the PWM frequency are reduced by 27 dB and 18 dB respectively. Total system efficiency is 79% at 40 W output power. ",

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AU - Lokin, Christiaan Egidius

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AU - Nauta, Bram

PY - 2020/3/1

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N2 - Class-D amplifiers switch high voltages and currents at high frequencies and hence produce electromagnetic interference (EMI). This work presents a technique to reduce the high frequency ripple, which is still present after the output filter. A Class-A ripple reduction amplifier is put in parallel to the output of the Class-D amplifier, each having their own feedback loop with digital filters. High ripple reduction loop gain is achieved at the PWM frequency by using a resonator as digital loop filter. Dissipation in the Class-A amplifier is reduced by using a low common-mode signaling technique. Common-mode and differential-mode switching components at the PWM frequency are reduced by 27 dB and 18 dB respectively. Total system efficiency is 79% at 40 W output power.

AB - Class-D amplifiers switch high voltages and currents at high frequencies and hence produce electromagnetic interference (EMI). This work presents a technique to reduce the high frequency ripple, which is still present after the output filter. A Class-A ripple reduction amplifier is put in parallel to the output of the Class-D amplifier, each having their own feedback loop with digital filters. High ripple reduction loop gain is achieved at the PWM frequency by using a resonator as digital loop filter. Dissipation in the Class-A amplifier is reduced by using a low common-mode signaling technique. Common-mode and differential-mode switching components at the PWM frequency are reduced by 27 dB and 18 dB respectively. Total system efficiency is 79% at 40 W output power.

KW - Audio power amplifier

KW - class-D amplifier

KW - ripple reduction

KW - delta-sigma analog to digital converter

KW - electromatic interference (EMI)

KW - BD modulation

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DO - 10.1109/TCSI.2019.2952543

M3 - Article

SN - 1549-8328

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JO - IEEE transactions on circuits and systems I: regular papers

JF - IEEE transactions on circuits and systems I: regular papers

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ER -

EMI reduction in Class-D amplifiers by actively reducing PWM ripple

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Keywords

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