A high-driving class-AB buffer amplifier with a new pseudo source follower

Abstract

A high-driving class-AB buffer amplifier, which consists of a high-gain input stage and a pseudo source follower, is proposed. The pseudo source follower consists of two same types of differential pairs rather than two complementary error amplifiers. The high-driving capability is mainly provided by the folded amplifiers. An experimental prototype buffer amplifier implemented in a 0.35-μm CMOS technology demonstrates that the circuit dissipates an average static power consumption of only 660 μW at a power supply of 3.3 V, and exhibits the slew rates of 2.7 V/μs and 3.8 V/μs for the rising and falling edges, respectively, under a 300Ω/150 pF load. The second and third harmonic distortions (HD2 and HD3) are −67 dB and −65 dB, respectively, at 20 KHz under the same load.