Organic light emitting display device and driving method of the same

An organic light emitting display device comprising:

• a timing controller that generates control signals to be applied to a plurality of pixels, each of the plurality of pixels including a pixel driving circuit,
• the timing controller including:
• a luminance measurement unit that receives pixel driving data and calculates a luminance value during an Nth frame;
• a memory unit that stores a luminance value calculated during an N−1th frame and the luminance value calculated during the Nth frame;
• an initialization voltage level controller that compares the luminance value of the N−1th frame and the luminance value of the Nth frame and generates an initialization voltage level control signal if there is a difference of a predetermined value or more in the luminance value;
• and
• an initialization voltage generator that supplies an adjusted initialization voltage to the pixel driving circuit in response to the initialization voltage level control signal.