Self-biased dual-path push-pull output buffer amplifier topology for LCD driver applications

Abstract

The present paper addresses an improved and compact low-power high-speed buffer amplifier topology for large-size liquid crystal display drivers. The proposed buffer achieves fast driving performance, draws a low quiescent current and offers a rail-to-rail common-mode input range. The circuit provides enhanced slewing and settling capabilities by realizing a dual-path push-pull operation of the output stage. No additional bias network is required to fix the quiescent conditions of the class-AB output stage, since the output static current is inherently controlled by the input differential stage itself without auxiliary power dissipation. Simulation results demonstrate that the suggested buffer can drive a 1000-pF column line capacitive load with a 5.8-V/µs slew-rate and a 0.75-µs settling time, while drawing only 3-µA quiescent current from a 3-V power supply.