关键词: AB类放大器, 多模式, 低功耗, 过流保护, 低失真

Abstract: An audio amplifier needs to be compatible with both headphone and speaker modes. When a class AB audio amplifier is in the headphone mode, the main operational amplifier is switched off, only slave operational amplifier drives the headphone load, and the power consumption of the amplifier can be significantly decreased. The improved class AB audio amplifier has a speaker mode output power of 3 W, a static power consumption of 32.5 mW in the headphone mode, and a total harmonic distortion (THD) of 0.02% in the two modes. The audio amplifier has low distortion rate and high quality sound. The over-current protect circuit is added to protect the chip in different load conditions, and the chip can be widely used in small electronic devices.

Key words: class AB amplifier, multi-mode, low power, over-current protect, low distortion