A compact low-power rail-to-rail class-B buffer for LCD column driver

Abstract

This paper proposes a compact, low-power, and rail-to-rail class-B output buffer for driving the large column line capacitance of LCDs. The comparator used as a nonlinear element in feedback path is modified from the current-mirror amplifier, which has area and power advantages. The output buffer was realized in a 0.35 mum CMOS process. The active area of the buffer is 86 X 73.5 mum(2). With a 3.3 V supply, the measured quiescent current is 7.4 muA. The settling time for 0.05-3.25 V swing to within 0.2% is 8 mus.