A High-Linearity and Low-EMI Multilevel Class-D Amplifier

Journal article (2020)

Authors

H. Zhang Electronic Instrumentation - EEMCS
S. Karmakar Electrical Engineering, Mathematics and Computer Science
Lucien Breems NXP Semiconductors
Quino Sandifort NXP Semiconductors
Marco Berkhout Goodix Technologies
K.A.A. Makinwa Microelectronics
Q. Fan Electronic Instrumentation - EEMCS
Research Group
Electronic Instrumentation (EEMCS) (TU Delft)
Copyright: © 2020 H. Zhang, S. Karmakar, Lucien J. Breems, Quino Sandifort, Marco Berkhout, K.A.A. Makinwa, Q. Fan
DOI: https://doi.org/10.1109/JSSC.2020.3043815
Class-D amplifiers Electromagnetic interference (EMI) Idle power Multilevel Pulsewidth modulation (PWM).
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Published Date

2020

Language

English

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Faculty

Electrical Engineering, Mathematics and Computer Science

Department

Microelectronics

Research Group

Electronic Instrumentation

Abstract

This article presents a Class-D audio amplifier for automotive applications. Low electromagnetic interference (EMI) and, hence, smaller LC filter size are obtained by employing a fully differential multilevel output stage switching at 4.2 MHz. A modulation scheme with minimal switching activity at zero input reduces idle power, which is further assisted by a gate-charge reuse scheme. It also achieves high linearity due to the high loop gain realized by a third-order feedback loop with a bandwidth of 800 kHz. The prototype, fabricated in a 180-nm high-voltage BCD process, achieves a minimum THD+N of -107.8 dB/-102 dB and a peak efficiency of 91%/87% with 8- and 4-Ω loads, respectively, while drawing 7-mA quiescent current from a 14.4-V supply. The prototype meets the CISPR 25 Class 5 EMI standard with a 5.7-dB margin using an LC filter with a cutoff frequency of 580 kHz.