A display device with built-in touch sensors, the display device comprising: a display panel where a pixel array with built-in touch sensors is driven in a time-sharing manner, separately in a display period (Td) and a touch sensing period (Tt), and the touch sensors and pixels share a common electrode; a display drive circuit (110, 120, 130, 140) adapted to write image data to the display panel during the display period (Td); a common voltage regulator adapted to output common voltage data (DVCOM1, DVCOM2) indicating the voltage level of a common voltage (VCOM) applied to the common electrode during the touch sensing period (Tt); and a touch sensing circuit adapted to receive the common voltage data (DVCOM1, DVCOM2) to vary the voltage level of the common voltage (VCOM), and to apply the varied common voltage (VCOM1, VCOM2, VCOM3) to the common electrode to drive the touch sensors during the touch sensing period (Tt), wherein the common voltage regulator is adapted to calculate an average value (Davg) of image data for each line of the pixel array, and to output the common voltage data (DVCOM1, DVCOM2) based on the calculated average value (Davg), wherein the common voltage regulator is adapted to calculate the average value (Davg) of image data written to the last pixel line during the display period (Td) wherein the common voltage regulator is adapted to output a first common voltage data (DVCOM1) for lowering the voltage level of the common voltage (VCOM), when the average value (Davg) of image data written to the last pixel line is at or above a preset threshold (Dth) and corresponds to positive data, and wherein the common voltage regulator is adapted to output second common voltage data (DVCOM2) for increasing the voltage level of the common voltage (VCOM) when the average value (Davg) of image data written to the last pixel line is at or above the preset threshold (Dth) and corresponds to negative data, wherein the touch sensing circuit is adapted to apply the common voltage (VCOM) to the common electrode during the display period (Td), and to apply to the common electrode during the touch sensing period (Tt) the first common voltage (VCOM1) having a lower voltage level than the common voltage (VCOM) or the second common voltage (VCOM2) having a higher voltage level than the common voltage (VCOM). a display panel where a pixel array with built-in touch sensors is driven in a time-sharing manner, separately in a display period (Td) and a touch sensing period (Tt), and the touch sensors and pixels share a common electrode; a display drive circuit (110, 120, 130, 140) adapted to write image data to the display panel during the display period (Td); a common voltage regulator adapted to output common voltage data (DVCOM1, DVCOM2) indicating the voltage level of a common voltage (VCOM) applied to the common electrode during the touch sensing period (Tt); and a touch sensing circuit adapted to receive the common voltage data (DVCOM1, DVCOM2) to vary the voltage level of the common voltage (VCOM), and to apply the varied common voltage (VCOM1, VCOM2, VCOM3) to the common electrode to drive the touch sensors during the touch sensing period (Tt), wherein the common voltage regulator is adapted to calculate an average value (Davg) of image data for each line of the pixel array, and to output the common voltage data (DVCOM1, DVCOM2) based on the calculated average value (Davg), wherein the common voltage regulator is adapted to calculate the average value (Davg) of image data written to the last pixel line during the display period (Td) wherein the common voltage regulator is adapted to output a first common voltage data (DVCOM1) for lowering the voltage level of the common voltage (VCOM), when the average value (Davg) of image data written to the last pixel line is at or above a preset threshold (Dth) and corresponds to positive data, and wherein the common voltage regulator is adapted to output second common voltage data (DVCOM2) for increasing the voltage level of the common voltage (VCOM) when the average value (Davg) of image data written to the last pixel line is at or above the preset threshold (Dth) and corresponds to negative data, wherein the touch sensing circuit is adapted to apply the common voltage (VCOM) to the common electrode during the display period (Td), and to apply to the common electrode during the touch sensing period (Tt) the first common voltage (VCOM1) having a lower voltage level than the common voltage (VCOM) or the second common voltage (VCOM2) having a higher voltage level than the common voltage (VCOM).