Slew-rate-enhanced rail-to-rail buffer amplifier for TFT LCD data drivers

Abstract

A high-slew-rate low-power rail-to-rail buffer amplifier, which is suitable for thin film transistor liquid crystal display (TFT LCD) data driver applications, is proposed. Previous dynamic biasing approaches become ineffective as an output signal approaches VDD or VSS supplies. However, the proposed buffer amplifier with a dynamic biasing circuit enhances the slew rate throughout the entire rail-to-rail signal range. The buffer amplifier and the previous counterparts were fabricated in a 0.35 mu m CMOS technology with 3.3 V supply voltage. Measurements show that the slew rate for rail-to-rail signal transition is enhanced from 0.80 V/mu s of a previous counterpart to 2.75 V/mu s.