Class-D Audio Amplifiers with Negative Feedback
Class-D Audio Amplifiers with Negative Feedback
复制标题
具有负反馈的 D 类音频放大器
DOI：
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复制
发表时间：
2005
影响因子：
1.9
通讯作者：
B. H. Candy
中科院分区：
文献类型：
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作者：
S. Cox;B. H. Candy
音频放大器有许多不同的设计。D类或开关放大器以可变占空比（导通时间与关断时间之比）的高频方波形式产生输出信号。输出的方波特性允许特别高效的输出级，具有最小的损耗。最终对输出进行滤波，以去除音频范围以上的频谱分量。数学模型推导出各种相关的D类放大器的设计，使用负反馈。这些模型使用与典型音频频率与开关频率的比率相关的小参数的幂的渐近展开，以开发音频频谱中的输出分量的幂级数。这些模型证实了这种放大器设计存在某种形式的固有失真。模型还解释了为什么商业上使用的两种方法在很大程度上成功地消除了这种失真，一种新的手段，克服固有的失真的分析。
版权所有（2006）工业与应用数学学会
There are many different designs for audio amplifiers. Class-D, or switching, amplifiers generate their output signal in the form of a high-frequency square wave of variable duty cycle (ratio of on time to off time). The square-wave nature of the output allows a particularly efficient output stage, with minimal losses. The output is ultimately filtered to remove components of the spectrum above the audio range. Mathematical models are derived here for a variety of related class-D amplifier designs that use negative feedback. These models use an asymptotic expansion in powers of a small parameter related to the ratio of typical audio frequencies to the switching frequency to develop a power series for the output component in the audio spectrum. These models confirm that there is a form of distortion intrinsic to such amplifier designs. The models also explain why two approaches used commercially succeed in largely eliminating this distortion; a new means of overcoming the intrinsic distortion is revealed by the analysis.
Copyright (2006) Society for Industrial and Applied Mathematics