Data driver and organic light emitting display device including the same

An organic light emitting display device comprising:

• a display region comprising a scan line, a data line, a line having a feedback function, and a pixel coupled to the scan line, the data line and the line having a feedback function;
• a scan driver for supplying scan signals to the scan lines in sequence;
• and
• a data driving part coupled to the data line and the line having a feedback function, the data driving part for supplying a data voltage as a data signal to the data line,
• wherein the data driving part comprises a data driver, the data driver comprising:
• a shift register part for generating sampling signals in sequence;
• a latch part for storing external data in response to the sampling signals;
• a current digital-analog converter for generating a data current corresponding to the data stored in the latch part;
• and
• a comparator comprising a first input terminal for receiving the data current, a second input terminal for receiving a pixel current, and an output terminal for outputting a current corresponding to a difference between the pixel current and the data current, wherein the comparator compares the pixel current with a data current, controls the data voltage by increasing or decreasing the current outputted through the output terminal thereof, and supplies the controlled data voltage to a pixel;
• and
• a first capacitor coupled to the output terminal of the comparator and for storing the data voltage, wherein before being supplied to the pixel, the data voltage is controlled by increasing or decreasing a current charging the first capacitor.

An organic light emitting display device comprising:

• a display region comprising a scan line, a data line, a line having a feedback function, and a pixel coupled to the scan line, the data line and the line having a feedback function;
• a scan driver for supplying scan signals to the scan lines in sequence;
• and
• a data driving part coupled to the data line and the line having a feedback function, the data driving part for supplying a data voltage as a data signal to the data line,
• wherein the data driving part comprises a data driver, the data driver comprising:
• a shift register part for generating sampling signals in sequence;
• a latch part for storing external data in response to the sampling signals;
• a current digital-analog converter for generating a data current corresponding to the data stored in the latch part;
• and
• a comparator comprising a first input terminal for receiving the data current, a second input terminal for receiving a pixel current, and an output terminal for outputting a current corresponding to a difference between the pixel current and the data current, wherein the comparator compares the pixel current with a data current, controls the data voltage by increasing or decreasing the current outputted through the output terminal thereof, and supplies the controlled data voltage to a pixel;
• and
• a first capacitor coupled to the output terminal of the comparator and for storing the data voltage, wherein before being supplied to the pixel, the data voltage is controlled by increasing or decreasing a current charging the first capacitor,
• wherein the comparator comprises:
• a first driver coupled like a diode when receiving the pixel current through the first input terminal, and enabling a first current therethrough;
• a second driver coupled with the first driver to form a current mirror, the second driver being coupled with the second input terminal, and enabling a second current therethrough;
• a third driver coupled with the output terminal, the third driver being coupled with the first driver to form a current mirror, and enabling the first current therethrough;
• a fourth driver for receiving the pixel current through the first input terminal and enabling a third current corresponding to the sum of the first current and the pixel current therethrough;
• a fifth driver coupled with the second input terminal, the fifth driver being coupled with the fourth driver to form a current mirror and enabling the third current therethrough;
• a sixth driver coupled like a diode when receiving the pixel current through the second input terminal, and enabling a fourth current therethrough;
• and
• a seventh driver coupled with the output terminal, the seventh driver being coupled with the fifth driver to form a current mirror, sending a current obtained by subtracting the pixel current from the data current to the output terminal by enabling the fourth current therethrough.

A data driver comprising:

• a shift register part for generating sampling signals in sequence;
• a latch part for storing external data in response to the sampling signals;
• a current digital-analog converter for generating a data current corresponding to the data stored in the latch part;
• and
• a comparator comprising a first input terminal for receiving the data current, a second input terminal for receiving a pixel current, and an output terminal for outputting a current corresponding to a difference between the pixel current and the data current,
• wherein the comparator compares the pixel current with a data current, controls the data voltage by increasing or decreasing the current outputted through the output terminal thereof, and supplies the controlled data voltage to a pixel.

A method for controlling image brightness in an organic light emitting display device having a pixel for emitting light and forming an image, the method comprising:

• generating a sampling signal;
• storing data in a register in response to the sampling signal;
• generating a data current corresponding to the stored data;
• comparing the data current with a pixel current generated in the pixel;
• generating an output current corresponding to a difference between the pixel current and the data current,
• controlling the data voltage by increasing or decreasing the output current;
• and
• supplying the controlled data voltage to the pixel to obtain a desired image brightness.