Patent ID: 7639217

Claim:
A scan driving circuit for an organic light emitting display device, the scan driving circuit comprising a plurality of stages coupled together in series, each stage coupled to an input line for receiving an input signal and an output line and being coupled to first and second power supplies, a first stage among the stages for receiving a start signal on the input line and each of the other stages having its input line coupled to the output line of a previous one of the stages having first and second clock terminals, each of the stages comprising: a transfer unit having a first transistor and a second transistor, the first transistor having a first terminal coupled to the input line, a gate coupled to the first clock terminal, and a second terminal coupled to a gate of the second transistor, the second transistor having a first terminal coupled to the second clock terminal; an inversion unit having a third transistor, a fourth transistor, and a fifth transistor, the third transistor having a first terminal coupled to the input line and a gate coupled to the first clock terminal, the fourth transistor having a second terminal coupled to the second power supply and a gate coupled with the first clock terminal, the fifth transistor having a first terminal coupled to the first clock terminal, a second terminal coupled to a first terminal of the fourth transistor, and a gate coupled to a second terminal of the third transistor; and a buffer unit having a sixth transistor, the sixth transistor having a first terminal coupled to the first power supply, a second terminal coupled to the output line, and a gate coupled to the second terminal of the fifth transistor.