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Convention Paper

Supply-Feedback Fully-Digital Class D Audio Amplifier Featuring 100 dBA+ SNR and 0.5 W to 1 W Selectable Output Power

Authors: Bassoli, Rossella; Guanziroli, Federico; Crippa, Carlo; Nicollini, Germano

AES Convention 135 · Paper 8968 · October 2013

Abstract

This paper presents a real-time power supply noise correction technique in a fully-digital class D audio amplifier. The power supply is scaled and applied to a 12-bits Nyquist ADC to modify the amplitude of the Pulse-Width-Modulator reference carrier. An improved supply extrapolation algorithm results to a power supply rejection from one to two orders of magnitude higher than reported implementations. Class D sensitivity to clock jitter is presented. SNR higher than 100dBA have been measured in the presence of both power supply ripple and clock jitter. The PWM and output stage are integrated in the same chip in a 0.13µm digital CMOS technology, whereas an external ADC has been used to demonstrate the validity of the supply-feedback algorithm.

Details

Published in
AES Convention 135
AES Convention
135
Paper number
8968
Publication date
October 6, 2013
Session subject
Amplifiers
Affiliation
ST-Ericsson, Monza Brianza, Italy (See document for exact affiliation information.)
Type
Convention Paper