Class-D audio amplifiers with negative feedback
There are many different designs for audio amplifiers. Class-D, or switching, amplifiers generate their output signal in the form of a high-frequency square wave of variable duty cycle (ratio of on time to off time). The square-wave nature of the output allows a particularly efficient output stage,...
| Main Authors: | , |
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| Format: | Article |
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2006
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| Online Access: | https://eprints.nottingham.ac.uk/501/ |
| _version_ | 1848790421916876800 |
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| author | Cox, Stephen M. Candy, B. H. |
| author_facet | Cox, Stephen M. Candy, B. H. |
| author_sort | Cox, Stephen M. |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | There are many different designs for audio amplifiers. Class-D, or switching, amplifiers generate their output signal in the form of a high-frequency square wave of variable duty cycle (ratio of on time to off time). The square-wave nature of the output allows a particularly efficient output stage, with minimal losses. The output is ultimately filtered to remove components of the spectrum above the audio range. Mathematical models are derived here for a variety of related class-D amplifier designs that use negative feedback. These models use an asymptotic expansion in powers of a small parameter related to the ratio of typical audio frequencies to the switching frequency to develop a power series for the output component in the audio spectrum. These models confirm that there is a form of distortion intrinsic to such amplifier designs. The models also explain why two approaches used commercially succeed in largely eliminating this distortion; a new means of overcoming the intrinsic distortion is revealed by the analysis.
Copyright (2006) Society for Industrial and Applied Mathematics |
| first_indexed | 2025-11-14T18:12:21Z |
| format | Article |
| id | nottingham-501 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| last_indexed | 2025-11-14T18:12:21Z |
| publishDate | 2006 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-5012020-05-04T20:29:47Z https://eprints.nottingham.ac.uk/501/ Class-D audio amplifiers with negative feedback Cox, Stephen M. Candy, B. H. There are many different designs for audio amplifiers. Class-D, or switching, amplifiers generate their output signal in the form of a high-frequency square wave of variable duty cycle (ratio of on time to off time). The square-wave nature of the output allows a particularly efficient output stage, with minimal losses. The output is ultimately filtered to remove components of the spectrum above the audio range. Mathematical models are derived here for a variety of related class-D amplifier designs that use negative feedback. These models use an asymptotic expansion in powers of a small parameter related to the ratio of typical audio frequencies to the switching frequency to develop a power series for the output component in the audio spectrum. These models confirm that there is a form of distortion intrinsic to such amplifier designs. The models also explain why two approaches used commercially succeed in largely eliminating this distortion; a new means of overcoming the intrinsic distortion is revealed by the analysis. Copyright (2006) Society for Industrial and Applied Mathematics 2006 Article PeerReviewed Cox, Stephen M. and Candy, B. H. (2006) Class-D audio amplifiers with negative feedback. SIAM Journal on Applied Mathematics, 66 (2). pp. 468-488. class-D amplifier; total harmonic distortion; mathematical model |
| spellingShingle | class-D amplifier; total harmonic distortion; mathematical model Cox, Stephen M. Candy, B. H. Class-D audio amplifiers with negative feedback |
| title | Class-D audio amplifiers with negative feedback |
| title_full | Class-D audio amplifiers with negative feedback |
| title_fullStr | Class-D audio amplifiers with negative feedback |
| title_full_unstemmed | Class-D audio amplifiers with negative feedback |
| title_short | Class-D audio amplifiers with negative feedback |
| title_sort | class-d audio amplifiers with negative feedback |
| topic | class-D amplifier; total harmonic distortion; mathematical model |
| url | https://eprints.nottingham.ac.uk/501/ |