Power-efficient class AB CMOS buffer

A novel class AB unity gain voltage buffer is proposed. It is based on the use of quasi-floating gate (QFG) techniques in a super source follower topology. The circuit achieves dynamic current boosting with accurate control of quiescent currents and without penalty in supply voltage requirements or quiescent power consumption. Measurement results of the circuit, fabricated in a 0.5 µm CMOS technology, show a slew-rate enhancement by a factor 18.5 against the conventional super source follower, for the same bias current and supply voltage.