一款用于驱动耳机的低噪声低功耗音频功率放大器的设计

报道了一款低噪声、低功耗、增益可调的音频功率放大器的设计.该功率放大器在电源电压为5V,输入信号频率为1kHz,驱动负载为16Ω,输出功率为120mW时的总谐波失真仅为0.1%.此音频功率放大器的增益允许以每台阶为1.5dB在+12～-34.5dB之间变化,共32个台阶,内部的放大器电路是该用于驱动耳机的音频功率放大器的核心.介绍了功率放大器的电路结构、放大器的主要模块、最终版图和测试结果,最后此电路在上华0.6μm双层多晶硅、双层金属的CMOS工艺上实现.

Design of a Low Noise, Low Power Audio Power Amplifier for Driving Headphones

This paper describes the design and implementation of a low noise, low power,programmable-gain audio power amplifier used as a headphone driver. It obtains a 0.1% THD + N with a 5V power-supply, a 1kHz frequency audio signal,and a 120mW continuous average output power into a 16Ω load. In addition, the gain can be set from + 12 to - 34.5dB in 32 discrete steps of 1.5dB. The amplifier is used as the core of a programmable gain audio power amplifier for driving headphones. The audio power architecture, the main module circuits of the amplifier design, the test results, and the chip layout are included. Experimental results using a CSMC 0. 6μm double poly double metal CMOS process show that the required performance can be obtained.