摘要
进入21世纪以后，各种便携式的电子设备成为了电子设备的一种重要的发展趋势。
从作为通信工具的手机，到作为娱乐设备的MP3播放器，已经成为差不多人人具备的便携式电子设备。所有这些便携式的电子设备的一个共同点，就是都有音频输出，也就是都需要有一个音频放大器。从中可知，音频放大器的重要性不言而喻。
因此，设计了由电流串联负反馈放大电路、电压并联负反馈放大电路以及OTL功率放大器三级组成的音频放大器。其中第一级用来尽可能不失真地保留音频信号，第二级用来做过渡，用以更好的驱动OTL功率放大器；而OTL功率放大器则使得能够带动大的负载。能够较好的进行音频的放大。
Abstract
Enter after twenty-first Century, all kinds of portable electronic devices has become an important development trend of electronic equipment.
As a communication tool from the mobile phone, as entertainment equipment，MP3 plyer portable electronic devices has become almost everyone has. A common point of all these portableelectronic devices, is to have the audio output, also is the need to have an audio amplifier. From the show, self-evident importance of audio amplifier.
Therefore, designed by series negative current feedback amplifier circuit, voltage parallel negative feedbackamplifying circuit and OTL power amplifier is composed of three stage of audio amplifier. The first stage is used toretain as much as possible without distortion of audio signal, second stage is used to do the transition, is used to drive the OTL power amplifier is better; and the OTL power amplifier is enabled to drive big load. Can better audioamplifier.
当下，从作为通信工具的手机，到作为娱乐设备的MP3播放器，已经成为差不多人人具备的便携式电子设备。基本上每个电子设备都需要音频的输出，因此，一个质量高，成本低的优质音频放大器必不可少。
掌握音频放大器的设计，有助于加深对负反馈以及OTL功率放大器的理解，并且初步认知掌握了音频放大器的设计流程，以及性能指标。对以后的学习有着巨大的推进作用。
图2-1-1 音频放大器模型
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