Organic light emitting diode display and driving method thereof

An organic light emitting diode display, comprising:

• a display panel having a plurality of data lines, a plurality of gate lines, and a plurality of pixels, wherein each of the pixels include an organic light emitting diode, a switch transistor and a driving transistor, wherein the switch transistor is turned-on by a scanning pulse from the gate line, and the driving transistor is turned-on by an analog data voltage to drive the organic light emitting diode, wherein the switch transistor and the driving transistors have a same channel type;
• a timing controller configured to control a driving timing of the inputted video data and controlling a supply timing of a refresh voltage;
• a refresh voltage generator configured to generate the refresh voltage for removing a gate discharge voltage of the driving transistor;
• a gamma reference voltage generator configured to generate a gamma reference voltage;
• a data driver configured to convert a digital data which is outputted from the timing controller for a current frame into the analog data voltage on the basis of the gamma reference voltage to supply the analog data voltage to a gate electrode of the driving transistor via the data lines, and then supply the refresh voltage from the refresh voltage generator to the gate electrode of the driving transistor via the data lines in accordance with a control of the timing controller;
• and
• a gate driver configured to sequentially supply a first scanning pulse for a first horizontal period in the current frame to all of the gate lines and then sequentially supply a second scanning pulse for a second horizontal period in the current frame to gate lines excepting some of gate lines positioned at upper portion of the display panel, in accordance with a control of the timing controller,
• wherein the first scanning pulse selects all of the pixels to be supplied with the analog data voltage, and
• wherein the second scanning pulse selects some of the pixels to be supplied with the refresh voltage.