Semiconductor device for driving liquid crystal display panel

Abstract

An improvement of the LCD driving semiconductor IC which supplies a plurality of source driving voltages (corresponding to the horizontal scanning voltage of a CRT) to a plurality of source driving lines of an active matrix type LCD of TFT base is proposed. Each of sample/hold circuit that is provided in one-to-one correspondence to the source driving lines which carry out polarity inversion and extraction of voltage sample values of an image signal for every one line of horizontal scanning of applied voltages to liquid crystal cells for the purpose of preventing the deterioration of liquid crystal cells consisting of pixel display electrodes and counter electrodes of LCD and a liquid crystal material inserted between the electrodes, is composed of complementarily operating first circuit part and second circuit part, and the correspondence relation between polarity display pulse that controls the complementary operation of these circuit parts and the polarity of the voltage sample value, and these first/second circuit parts is fixed. By so doing, the variation range of the input voltage to each buffer amplifier of the first/second circuit parts was limited, the source-drain region formation process of the input transistor of its amplifier was simplified, and facilitated the improvement of the accuracy of the source driving voltage with respect to the input image signal.