A novel low-power high-speed rail-to-rail class-B buffer amplifier for LCD output drivers

This paper addresses a new compact low-power class-B buffer amplifier topology for large-size liquid crystal display applications. The proposed buffer achieves high-speed driving performance, draws a low quiescent current during static operation and offers a rail-to-rail common-mode input range. The circuit provides enhanced slewing capabilities with a limited power consumption by exploiting two current comparators embodied in the input stage, which sense the input signal transients to turn on the output stage transistors. A rail-to-rail stacked mirror differential amplifier is used to amplify the input signal difference and supply the bias voltages for the output stage. Simulation results show that the proposed buffer can drive a 1-nF column line load within 1.8-μs settling time under a full voltage swing, while drawing only 3.5-μA static current from a 3-V power supply.