A 121.4dB DR, -109.8dB THD+N Capacitively-Coupled Chopper Class-D Audio Amplifier

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Class-D amplifiers (CDAs) are often used in audio applications due to their superior power efficiency. Due to the sensitivity of the human ear, a large dynamic range (DR) is desired, and audio DACs with up to 130dB DR are commercially available [1]. However, the DR of the CDAs they drive is typically much lower [2]-[4], mainly due to the thermal noise introduced by the input resistors of their resistive feedback networks. Reducing this resistance is difficult, as it reduces the CDA's input impedance and increases the required loop-filter capacitance. Alternatively, the CDA could be configured as a capacitively coupled chopper amplifier (CCCA), whose capacitive feedback network could then achieve low noise without reducing input impedance. However, the large PWM component present at its output would then saturate its input stage. By exploiting the inherent PWM filtering present in a feedback-after-LC architecture, this paper presents a capacitively coupled chopper CDA, resulting in significantly improved DR and THD+N. The prototype achieves 8V_RMS of integrated output noise (A-weighted), a 121.4dB DR, and -1 09.8dB THD+N while delivering a maximum of 15/26W into an 8/4Omega load with 93%/88% efficiency.

Original languageEnglish
Title of host publication2022 IEEE International Solid- State Circuits Conference (ISSCC)
Subtitle of host publicationDigest of technical papers
EditorsLaura C. Fujino
Place of PublicationDanvers
Number of pages3
ISBN (Electronic)978-1-6654-2800-2
ISBN (Print)978-1-6654-2801-9
Publication statusPublished - 2022
Event2022 IEEE International Solid- State Circuits Conference (ISSCC) - Online at San Francisco, United States
Duration: 20 Feb 202226 Feb 2022

Publication series

NameDigest of Technical Papers - IEEE International Solid-State Circuits Conference
ISSN (Print)0193-6530


Conference2022 IEEE International Solid- State Circuits Conference (ISSCC)
Abbreviated titleISSCC 2022
Country/TerritoryUnited States
CityOnline at San Francisco

Bibliographical note

Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care
Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

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