Fast switching charge dump assisted Class-D audio amplifier with high fidelity and high efficiency

A fast switching charge dump assisted Class-D audio amplifier is presented in this paper. To achieve high efficiency and high linearity, the Class-K* audio amplifier consists of the Class D amplifier with high efficiency and the proposed charge dump amplifier with high linearity. The charge pump amplifier works at faster switching frequency than Class D amplifier so as to compensate the distortion caused by switching of the Class-D amplifier. The Class-K* audio amplifier implemented in 0.35μm CMOS process shows −71.8 dB THD+N at 1 KHz and a maximum efficiency of 81% at an output power of 257mW for 4.1Ω load.