Offset-compensated operational amplifier for gray voltage generation of 262,144 color QVGA LCD driver IC

In this paper, a new amplifier structure including voltage-current converter is presented. Also, we present a structure of source driver and gray voltage generator in LCD (liquid crystal display) driver IC (integrated circuit) for mobile application. By using the proposed amplifier structure that makes the random dc offset of amplifiers reduced, we reduced a gap fail of gray voltage levels and enhanced IC yield. Also, it is advantageous to frequency compensation and gain because it has a constant transconductance independent of input voltage range. The presented LCD driver IC has 262,144 color depth (6-bit for each RGB signal), 720 source and 320 gate channels. And the IC was fabricated using a 0.18/0.S/3.0 mum mixed CMOS technology for 1.8/6/30 V supply voltage.