A touch display device can include a controller configured to output a synchronization signal having a first level during a display driving interval and having a second level during a touch driving interval; a power output circuit configured to receive the synchronization signal from the controller, in response to receiving the synchronization signal having the first level, set an output value of a high-potential voltage to a first voltage, and in response to receiving the synchronization signal having the second level, set the output value of the high-potential voltage to a second voltage that is lower than the first voltage; and a data driving circuit configured to receive image data from the controller, and output data voltages according to the image data by using the high-potential voltage received from the power output circuit to power the data driving circuit.