Patent ID: 7463236

Claim:
A driver circuit that is connected to a light emitting device to supply a current to the device, comprising: a driver transistor that provides the light emitting device with the current; and a negative voltage generation circuit that generates a negative voltage based on a positive power supply voltage supplied to an anode of the light emitting device, the negative voltage being supplied to a cathode of the light emitting device through the driver transistor, wherein the negative voltage generation circuit comprises a first switching device having an input terminal to which a ground voltage is applied, a second switching device connected to the first switching device in series, a first capacitor comprising a terminal to which a clock is applied, a second capacitor comprising a terminal that is connected to a connecting point between the first switching device and the second switching device, a third switching device connected between another terminal of the second capacitor and a ground that is at the ground voltage, a fourth switching device connected between another terminal of the first capacitor and the another terminal of the second capacitor, and a fifth switching device connected between the another terminal of the first capacitor and an output terminal of the second switching device, and wherein the first switching device and the fourth switching device are turned on so that the first capacitor and the second capacitor are connected in series between a clock source and the ground through the first switching device and the first and second capacitors are charged when the clock source supplies a first voltage as the clock, and the fifth switching device is turned on so that the first capacitor is connected between the ground and the output terminal for the first capacitor to be discharged, and the second switching device and the third switching device are turned on so that the second capacitor is connected between the ground and the output terminal through the second switching device for the second capacitor to be discharged when the clock source supplies a second voltage as the clock.