Display device having touch sensor reducing limit in driving time of pixel array and driving time of touch sensor and method for driving the same

A method of operating a touch-sensitive display device, the touch-sensitive display device including a display panel, a touch screen, a display driving circuit and a touch screen driving circuit, the display panel including data lines, gate lines crossing the data lines, and a pixel array including pixels arranged in a matrix form, the touch screen including Tx lines, Rx lines crossing the Tx lines, and touch sensors formed at crossings of the Tx lines and the Rx lines, the display driving circuit configured to supply video data voltages to the pixels of the display panel, the method comprising:

• operating the touch screen using the touch screen driving circuit, wherein the operating step includes:
• sequentially supplying, by the touch screen driving circuit, at least one delayed pulse of a plurality of delayed pulses to each of the Tx lines of the touch screen, wherein a falling edge of each of the at least one delayed pulse supplied to the Tx lines of the touch screen is present in a horizontal blank period of gate voltages to the pixels of the display panel, and
• sampling, by the touch screen driving circuit, an output signal of each of the touch sensors through the Rx lines in synchronization with the falling edge of each of the at least one delayed pulse of the plurality of delayed pulses supplied to the Tx lines of the touch screen within the horizontal blank period of gate voltages supplied to the pixels of the display panel, and
• wherein the horizontal blank period corresponds to a period when data is not written to the pixels.