一种低功耗、高保真音频功率放大器的研发

A Design of Low Voltage,Low Distortion Class AB Power Amplifier for Audio Application

就解决现有音频功率放大器中噪声高、失调大的问题,设计制作了一种0.6μm线宽的低压、低失真AB类音频功率放大器.器件采用BTL结构的差动输出,以简单的结构达到高质量音频重现.在设计中,采用前馈式AB类控制方式解决静态电流的控制,并增加浮动AB类控制减小失配,改善了传统AB类放大在噪声、失调等方面的性能.实验测试结果表明,供电电压为5 V时在关断模式下,将静态电流消耗减小到0.2μA以下;电源抑制比高于80 dB;总谐波失真在1%内.

In order to improve traditional audio power amplifiers the noise and offset performance, we design a low-cost,stereo audio power amplifier. The audio power amplifiers are ideal for portable audio devices with internal speakers. Abridge-tied load （BTL） architecture minimizes external component count, while providing high-quality audio reproduction. We used feedforward Class AB control to solve the quiescent current control,improving the noise and offset performance. The test results in low-power shutdown mode,reducing quiescent current consumption to less than 0.2 μA; power supply rejection rate（PSRR） could reach 80 dB and the total harmonic distortion （THD） is less than 1% while operating from a single ＋5 V supply.