JSSC 2023第12期Data Converters180nmDACNeural Network Accelerator

A 120.9-dB DR Digital-Input Capacitively Coupled Chopper Class-D Audio Amplifier

一种采用斩波电容反馈网络和电容DAC的数字输入D类音频放大器，实现120.9 dB动态范围。

180nm BCD, 120.9 dB DR, -111.2 dB THD+N, 15/26W@8/4Ω, 90%/86%效率

D类放大器斩波稳定电容DAC动态范围音频功放

▸斩波电容反馈网络消除DAC和反馈电阻噪声

▸实时动态元件匹配(RTDEM)降低DAC失配失真

▸死区消除DAC的码间干扰(ISI)

Abstract

This article presents a digital-input class-D ampli- fier (CDA) achieving high dynamic range (DR) by employing a chopped capacitive feedback network and a capacitive digital-to-analog converter (DAC). Compared with conventional resistive-feedback CDAs driven by resistive or current-steering DACs, the proposed architecture eliminates the noise from the DAC and feedback resistors. Intermodulation between the chopping, pulsewidth modulation (PWM), and DAC sampling frequency is analyzed to avoid negative impacts on the DR and linearity. Real-time dynamic element matching (RTDEM) is employed to address distortion due to mismatch in the DAC, while its intersymbol interference (ISI) is eliminated by deadbanding. The prototype, implemented in a 180-nm bipolar, CMOS, and DMOS (BCD) process, achieves 120.9 dB of DR and a peak total harmonic distortion plus noise (THD+N) of −111.2 dB. It can drive a maximum of 15/26 W into an 8-/4- load with a peak efficiency of 90%/86%.