A 0.0004% (-108dB) THD+N, 112dB-SNR, 3.15W Fully Differential Class-D Audio Amplifier with Gm Noise Cancellation and Negative Output-Common-Mode Injection Techniques

📋 论文概要

本文提出一种采用Gm噪声消除技术的全差分D类音频放大器，有效抑制1/f噪声并避免传统斩波引起的混叠和线性度下降。实现了0.0004% THD+N（-108dB）、112dB SNR和3.15W输出功率，适用于高保真音频应用。

💡 主要创新点

• 提出Gm噪声消除（GmNC）技术，在不影响线性度的前提下抑制1/f噪声，替代传统斩波方法。
• 采用全差分脉冲宽度调制（PWM）架构，实现高功率输出（3.15W）同时保持极低失真。

📄 原文摘要

techniques are commonly adopted approaches to mitigate 1/f noise. However, the choppers are seldom used in pulse-width-modulation (PWM) Class-D audio amplifiers (CDAs) because the conventional chopping method applied in the opamps along the signal path of CDAs inevitably results in extra aliasing and deteriorates the linearity. Therefore, a CDA with high SNR and low total harmonic distortions (THDs) has become a challenging design to ensure high-fidelity audio applications. In this work, the Gm-noise-cancellation (GmNC) technique is introduced in the CDA to suppress the 1/f noise for the SNR improvement, further improving the linearity of the CDA. Moreover, the negative output common-mode injection (NOCMI) technique is introduced to improve the linearity by reducing the voltage fluctuation of the input common-mode (CM) of the first opamp of the CDA. This CDA achieves 0.0004% (–108dB) THD+N and 112dB SNR (A-weighted), and is

👥 作者与机构

Wen-Chieh Wang, Yu-Hsin Lin, MediaTek, Hsinchu, Taiwan, Flicker (1/f) noise is a main design issue when realizing a low-noise and highSNR audio amplifier. Utilizing large device sizes and chopper-stabilization