Self-biased class AB CMOS current buffer

Abstract

A self-biased current buffer based on the quasi floating gate (QFG) approach to achieve class AB operation is presented in this paper. It was designed in standard 0.18μm CMOS process with 1.8V power supply. The buffer is able to copy an input current range of ±15μA with 8μA bias current. The total harmonic distortion (THD) remains below -84dB for 1 kHz frequency and maximum input current Ipp = 30pA. A comparison with two other class AB architectures in terms of input and output impedances, THD, bandwidth, accuracy and static and dynamic power consumption is also presented.