Organic light emitting display device and method of driving the same

An organic light emitting diode comprising:

• a scan driver supplying scan signals to scan lines;
• a data driver supplying reference power to data lines during a primary period of a period while the scan signals are supplied, and supplying data signals during a secondary period of the period other than the primary period;
• and
• a plurality of pixels positioned in the intersections of the scan lines and the data lines, wherein each pixel comprises:
• an organic light emitting diode whose cathode electrode is connected to a second power supply;
• a first transistor and a fourth transistor connected between an anode electrode of an organic light emitting diode and a first power supply;
• a second transistor connected between a gate electrode of the first transistor and the data line, and turned on when a scan signal is supplied to a first scan line;
• a third transistor connected between a common node of the first transistor and the fourth transistor and the data line, and turned on when a scan signal is supplied to the first scan line;
• a first capacitor connected between the gate electrode of the first transistor and the anode electrode of the organic light emitting diode;
• and
• a second capacitor connected between the anode electrode of the organic light emitting diode and a predetermined voltage source.