Patent ID: 7545354

Claim:
A driving circuit for an organic light emitting diode device comprising: an organic light emitting diode(OLED) formed at each of a plurality of RGB unit pixels being defined by a gate line arranged in a first direction and a data line arranged in a second direction crossing the gate line; a data driving portion for supplying a data voltage to the RGB unit pixel; a power supply portion for supplying a high potential voltage to the RGB unit pixel; a driving thin film transistor having a source terminal connected to the power supply portion and a drain terminal connected to the OLED to supply a current to the OLED; a first switching thin film transistor having a gate terminal connected to the gate line and a source terminal connected to the data line; a storage capacitor having terminals connected to the drain terminal of the first switching transistor and the gate terminal of the driving thin film transistor; a second switching thin film transistor having a drain terminal connected to the drain terminal of the first switching thin film transistor and the one terminal of the storage capacitor; a third thin film transistor having a source terminal connected to the power supply portion and a drain terminal connected to the gate terminal of the driving thin film transistor and one terminal of the storage capacitor; a variable voltage portion connected to one side node of the storage capacitor to which the data driving portion is connected through the second switching thin film transistor to supply a different voltage to each of RGB unit pixel; and at least one control signal supply portion including a first pulse signal portion and a second pulse signal portion generating and applying a first pulse signal or/and a second pulse signal to control the first to third switching thin film transistors, wherein the first to third switching thin film transistors maintain a data voltage charged to the storage capacitor by connecting the one side node of the storage capacitor to the variable voltage portion for supplying the variable voltage smaller than the data voltage and by floating electrically the other side node of the storage capacitor, and the first to third switching thin film transistors control the amount of current of the driving thin film transistor, wherein the first pulse signal portion is connected to the first switching thin film transistor and at least one switching thin film transistor of the second switching thin film transistor and the third switching thin film transistor and the second pulse signal portion is connected the other switching thin film transistor so that a first pulse signal is supplied to the switching thin film transistors connected to the first pulse signal portion to turn these on simultaneously and the second pulse signal is supplied to the switching thin film transistors connected to the second pulse signal portion to turn these on simultaneously.