Patent ID: 7663588

Claim:
A circuit for driving a liquid crystal display device, comprising: a gray level voltage generator for generating a plurality of gray level voltages; and an intermediate gray level voltage generator for receiving a first gray level voltage and a second gray level voltage among the plurality of gray level voltages and for selectively outputting one of the first gray level voltage and a third gray level voltage through a plurality of capacitors, a value of the third gray level voltage being between the first and second gray level voltage and set by the plurality of capacitors, the intermediate gray level voltage generator including: an operational amplifier for pre-charging the plurality of capacitors using a current outputted from the operational amplifier and for selectively outputting one of the first gray level voltage and the third gray level voltage, and a switching device for selectively switching connections among the gray level voltage generator, the plurality of capacitors and the operational amplifier, such that the operational amplifier selectively outputs one of the first gray level voltage and the third gray level voltage, wherein the switching device comprises: a 1st switch which is connected between a first input lead to which the first gray level voltage is inputted and a first node; a 2nd switch which is connected between a second input lead to which the second gray level voltage is inputted and the first node; a 3rd switch which is connected between the first input lead and an non-inverting lead of the operational amplifier; a 4th switch which is connected between a third input lead to which a reference voltage is inputted and the non-inverting lead of the operational amplifier; a 5th switch which is connected between the first node and the inverting lead of the operational amplifier; a 6th switch which is connected between the first node and a second node; a 7th switch which is connected between the second node and an output lead of the operational amplifier; an 8th switch which is connected between the output lead and an inverting lead of the operational amplifier; a 9th switch which is connected between the inverting lead and a third node; a 10th switch which is connected between the third node and the third input lead; and an 11th switch which is connected between the output lead of the operational amplifier and a data line of the liquid crystal display device; wherein the plurality of capacitors are a first capacitor and a second capacitor, the first capacitor being connected between the first node and the third node, the second capacitor being connected between the second node and the third node.