Ripple compensation for a class-D amplifier
This paper presents the first detailed mathematical analysis of the ripple compensation technique for reducing audio distortion in a class-D amplifier with negative feedback. The amplifier converts a relatively low-frequency audio signal to a high-frequency train of rectangular pulses whose widths a...
| Main Authors: | , |
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| Format: | Article |
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SIAM
2015
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| Online Access: | https://eprints.nottingham.ac.uk/30737/ |
| _version_ | 1848794047591743488 |
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| author | Cox, Stephen M. du Toit Mouton, Hendrik |
| author_facet | Cox, Stephen M. du Toit Mouton, Hendrik |
| author_sort | Cox, Stephen M. |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | This paper presents the first detailed mathematical analysis of the ripple compensation technique for reducing audio distortion in a class-D amplifier with negative feedback. The amplifier converts a relatively low-frequency audio signal to a high-frequency train of rectangular pulses whose widths are slowly modulated according to the audio signal (pulse-width modulation, PWM). Distortion manifests itself through unwanted audio-frequency harmonics that arise in the output due to nonlinearities inherent in the design. In this paper, we first develop a small-signal model, which describes the fate of small-amplitude perturbations to a constant input, and demonstrate how this traditional engineering tool may be extended to allow one to infer the most significant contributions to the full output in response to a general audio input. We then compute the audio output of the amplifier through a perturbation expansion based on the ratio between audio and switching frequencies. Our results explicitly demonstrate how the ripple compensation technique significantly linearizes the output, thereby reducing the distortion. |
| first_indexed | 2025-11-14T19:09:59Z |
| format | Article |
| id | nottingham-30737 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| last_indexed | 2025-11-14T19:09:59Z |
| publishDate | 2015 |
| publisher | SIAM |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-307372020-05-04T17:13:08Z https://eprints.nottingham.ac.uk/30737/ Ripple compensation for a class-D amplifier Cox, Stephen M. du Toit Mouton, Hendrik This paper presents the first detailed mathematical analysis of the ripple compensation technique for reducing audio distortion in a class-D amplifier with negative feedback. The amplifier converts a relatively low-frequency audio signal to a high-frequency train of rectangular pulses whose widths are slowly modulated according to the audio signal (pulse-width modulation, PWM). Distortion manifests itself through unwanted audio-frequency harmonics that arise in the output due to nonlinearities inherent in the design. In this paper, we first develop a small-signal model, which describes the fate of small-amplitude perturbations to a constant input, and demonstrate how this traditional engineering tool may be extended to allow one to infer the most significant contributions to the full output in response to a general audio input. We then compute the audio output of the amplifier through a perturbation expansion based on the ratio between audio and switching frequencies. Our results explicitly demonstrate how the ripple compensation technique significantly linearizes the output, thereby reducing the distortion. SIAM 2015-07-14 Article PeerReviewed Cox, Stephen M. and du Toit Mouton, Hendrik (2015) Ripple compensation for a class-D amplifier. SIAM Journal on Applied Mathematics, 75 (4). pp. 1536-1552. ISSN 1095-712X class-D amplifier mathematical model small-signal model Apostol–Bernoulli functions pulse-width modulation http://epubs.siam.org/doi/10.1137/140997695 doi:10.1137/140997695 doi:10.1137/140997695 |
| spellingShingle | class-D amplifier mathematical model small-signal model Apostol–Bernoulli functions pulse-width modulation Cox, Stephen M. du Toit Mouton, Hendrik Ripple compensation for a class-D amplifier |
| title | Ripple compensation for a class-D amplifier |
| title_full | Ripple compensation for a class-D amplifier |
| title_fullStr | Ripple compensation for a class-D amplifier |
| title_full_unstemmed | Ripple compensation for a class-D amplifier |
| title_short | Ripple compensation for a class-D amplifier |
| title_sort | ripple compensation for a class-d amplifier |
| topic | class-D amplifier mathematical model small-signal model Apostol–Bernoulli functions pulse-width modulation |
| url | https://eprints.nottingham.ac.uk/30737/ https://eprints.nottingham.ac.uk/30737/ https://eprints.nottingham.ac.uk/30737/ |