Patent ID: 7091945

Claim:
A drive circuit to drive an electro-optical device that includes a plurality of signal electrodes and a plurality of scanning electrodes intersecting the signal electrodes, the drive circuit comprising: a dummy scanning electrode provided next to at least one of the scanning electrodes; an operational amplifier, wherein an inverting input terminal is connected to one end of the dummy scanning electrode, a non-inverting input terminal is connected to a reference voltage, and a resistor is connected between the inverting input terminal and an output terminal; a counter circuit that receives a scanning-period determining signal and a gradation determining signal, wherein the counter circuit determines times of switching between an off period and an on period and counts times of rising of the gradation determining signal and resets a counter value in synchronization with the scanning period determining signal; and a decoder connected to at least one output terminal of the counter circuit and the operational amplifier, and selectively outputs a voltage which is given by resistance division of the output voltage of the operational amplifier in accordance with the counter value, wherein the decoder gradually switches a switching terminal for the resistance division such that the greater the counter value is, the lower the voltage output is, and superimposes voltage output on a selection voltage which is applied to the scanning electrodes.