A class-B output buffer for flat-panel-display column driver

Abstract

Due to the large number of output buffers on a column driver chip of a hat-panel display, the quiescent current and die area of the output buffer must be minimized. This paper presents a low static power, Large output swing, and wide operating voltage range class-B output buffer amplifier for driving the large column Line capacitance in flat-panel display. rt comparator is used in the negative feedback path to eliminate quiescent current in the output stage. The proposed output buffer circuit was implemented in a 0.8-mu m CMOS process. Its output voltage suing is from 1 V to the supply voltage, With 5-V supply and 600-pF toad, the maximum tracking error is +/-7 mV. The measured static current is 24 mu A. The settling time for 4-V suing to within 0.2% is 8 mu s, which is more than adequate for driving 1280 x 1024 pixels Liquid crystal displays with 86-Hz frame rate and 256 gray levels in each color.