Title
A 28W -108.9dB/-102.2dB THD/THD+N Hybrid ΔΣ-PWM Class-D Audio Amplifier with 91% Peak Efficiency and Reduced EMI Emission
Author
Karmakar, S. (TU Delft Electronic Instrumentation) 
Zhang, H. (TU Delft Electronic Instrumentation)
Van Veldhoven, Robert (NXP Semiconductors)
Breems, Lucien (NXP Semiconductors)
Berkhout, M. (NXP Semiconductors)
Fan, Q. (TU Delft Electronic Instrumentation)
Makinwa, K.A.A. (TU Delft Microelectronics)
Department
Microelectronics
Date
2020
Abstract
Class-D amplifiers are often used in high-power audio applications due to their high power efficiency. They typically employ pulse-width modulation (PWM) at a fixed carrier frequency, which may cause electromagnetic interference (EMI). Setting this frequency fPWM) below the AM band (535 to 1605kHz) helps mitigate this, but its harmonics still contain substantial energy and must be filtered out by bulky LC filters with low cut-off frequencies (fc = 20 to 40 kHz), significantly increasing system cost and size. Stability considerations also constrain the amplifier's unity-gain frequency to be < mathrm{f} {mathrm{PWM}}/pi [1], compromising the audio-band loop gain required to suppress output-stage nonlinearity. Setting fPWM above the AM band helps increase fc and allows a higher loop gain [2]. However, this results in narrower pulses at higher power levels (higher modulation index), which cannot be faithfully produced by the output stage, thus exacerbating its non-linearity. Delta-sigma modulation (DeltaSigma M) has fixed pulse widths and does not suffer from these narrow-pulse artefacts. However, the out-of-band noise of 1bit modulators then requires larger LC filters. Moreover, high-order loop filters must be used to achieve sufficient SQNR, which then require additional techniques to maintain stability as the modulation range approaches 100% [3].
To reference this document use:
http://resolver.tudelft.nl/uuid:c115140d-bbc3-4a62-a36e-4c9c1476f850
DOI
https://doi.org/10.1109/ISSCC19947.2020.9063001
Publisher
IEEE
Embargo date
2022-03-25
ISBN
978-1-7281-3206-8
Source
2020 IEEE International Solid-State Circuits Conference, ISSCC 2020
Event
2020 IEEE International Solid-State Circuits Conference, ISSCC 2020, 2020-02-16 → 2020-02-20, San Francisco, United States
Series
Digest of Technical Papers - IEEE International Solid-State Circuits Conference, 0193-6530, 2020-February
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.
Part of collection
Institutional Repository
Document type
conference paper
Rights
© 2020 S. Karmakar, H. Zhang, Robert Van Veldhoven, Lucien Breems, M. Berkhout, Q. Fan, K.A.A. Makinwa