适用于D类音频功放的动态迟滞PWM比较器

系统介绍了基于PWM（Pulse Width Modulation）调制的D类音频功率放大器的原理及
特点。针对传统比较器迟滞固定的不足，通过引入两路电流反馈，设计了一种新颖的动态迟滞PWM比较器。同等分辨率下，其抗噪声能力远好于传统的比较器。电路的设计基于TSMC0.6μm BCD工艺。Spectre仿真结果表明，在载波以及输出的不同状态下，比较器的迟滞在20 mV与80 mV之间切换，并且其增益高达79 dB，单位增益带宽大于10 MHz。
关键词：PWM 调制；D 类音频功放；动态迟滞比较器
A dynamic hysteresis PWM comparator applied to Class D audio amplifier
Jin Jie1，Wu Chuan-xin1，Xu-Ziyou2
（1．School of Mechano-electronic Engineering，Xidian Univ．，Xi′an 710071，China；
2．School of Electronic Engineering，Xidian Univ．，Xi′an 710071，China）
Abstracts：A systematic introduction to principles and advantages of the class D audio amplifier
based on pulse width modulation （PWM） is presented. Considering the disadvantages of the
traditional fixed hysteresis comparator, a novel dynamic hysteresis PWM comparator with two
paths of current feedback is proposed. Compared with traditional comparators, the proposed
circuit has a better anti-noise character at the same resolution ratio. The circuit is designed with
TSMC 0.6μm BCD technology．Cadence Spectre-based simulation shows that the hysteresis
changes between 20 mV and 80 mV according to different states of the carrier and output, while
its gain is up to 79 dB and unity gain bandwidth is greater than 10 MHz.
Keywords: PWM; Class D audio amplifier; dynamic hysteresis comparator.