A slew-rate enhancement technique for fully differential amplifier without inducing Trojan state

A simple slew-rate enhancement (SRE) technique for fully-differential amplifier is proposed in this paper. The proposed SRE feedback is only valid during slewing, while completely blocked at DC for avoiding multiple operating points problem. The advantage of the proposed SRE method is that both positive and negative slew-rate of fully-differential amplifier can be equally improved with a very small static power overhead. The simulation result shows that the average slew-rate for a fully-differential folded-cascode amplifier can be enhanced by factor of 2.6 and the 1% settling time is reduced by 30% by comparing with the one without SRE. With such improvement, each stage of the amplifier can achieve equal slew-rate for maximizing overall slew-rate of the amplifier.