高保真音频功放器设计

摘要

针对高品质音频的需求,设计了一种高保真音频放大器.该音频放大器主要由信号放大电路、功率放大电路和有源滤波电路组成,其中信号放大部分采用场效应管及运算放大器.其受外界的干扰性较小,稳定性较高,放大倍数可达到20～30倍,随需要而进行调节.功放部分采用LM4766型芯片,采用差动放大电路对信号实现音频信号的放大,失真小于百分之零点一.滤波电路采用了二阶有源低通滤波电路,对输入的音频信号进行处理.该设计的音频功率放大器具有失真度小、增益可调、体积小等特点,具有较高的实用价值.%According to the demand of high quality audio, a high-fidelity audio amplifier was designed. The audio amplifier is mainly composed of a signal amplifying circuit, a power amplification circuit and an active filtering circuit, MOSFET and operational amplifier are adopted in the signal amplification part. It bears less external interference and has high stability. Its amplification factor can reach 20~30 times, which can be regulated according to the demand, LM4766 chip is adopted in the power amplifier section. A differential amplification circuit is adopted to realize the audio signal amplification and reduce the distortion less than 0.1%. The second-order active low-pass filtering circuit is adopted in the filter circuit to process the input audio signal. The audio power amplifier designed in this paper has the advantages of small distortion, adjustable gain and small volume, and has a high practical value.