Patent ID: 6864873
Filing Date: 2005-03-08
Classification: G09G,Y10S

Abstract:
1. A semiconductor integrated circuit for driving a liquid crystal panel comprising: data latches holding n bit digital image data, input externally, each said data latch comprising a positive data latch holding n bit digital image data for generating a positive analog gradation voltage and a negative data latch holding n bit digital image data for generating a negative analog gradation voltage; a positive gradation voltage generating portion generating positive analog gradation voltages of different gradation levels on respective, positive gradation voltage lines; a negative gradation voltage generating portion generating negative analog gradation voltages of different gradation levels on respective, negative gradation voltage lines; positive selectors, arranged immediately above said positive gradation voltage lines and not arranged above said negative gradation voltage lines, selecting positive analog gradation voltages of respective, different gradation levels generated by said positive gradation voltage generating portion, in accordance with the n-bit digital image data held by said positive data latches, each said positive selector selecting said positive analog gradation voltage in accordance with the n-bit digital image data held by a respective said positive data latch; negative selectors arranged immediately above said negative gradation voltage lines and not arranged above said positive gradation voltage lines, and selecting negative analog gradation voltages of respective, different gradation levels generated by said negative gradation voltage generating portion in accordance with the n-bit digital image data held by said respective data latches, each said negative selector selecting said negative analog gradation voltage in accordance with the digital image data held by a respective said negative data latch; an operational amplifier amplifying and outputting the positive analog gradation voltages and the negative analog gradation voltages respectively selected by said positive selectors and said negative selectors, said operational amplifier including positive operational amplifiers amplifying and outputting the positive analog gradation voltages selected by said positive selectors and negative operational amplifiers amplifying and outputting the negative analog gradation voltages selected by said negative selectors; an output switching portion supplying the positive analog gradation voltages and the negative analog gradation voltages output by said operational amplifiers to a liquid crystal panel by switching signal paths for said positive analog gradation voltages and said negative analog gradation voltages between straight and cross, wherein: