A driver integrated circuit (IC), arranged to selectively operate in a display mode, a self-capacitor mode and a mutual-capacitor mode when the driver IC is coupled to a touch display panel, wherein when the driver IC operates in the display mode, the driver IC outputs display data to a plurality of source lines of the touch display panel; when the driver IC operates in the self-capacitor mode, the driver controls the source lines to have a predetermined voltage; and when the driver IC operates in the mutual-capacitor mode, the driver IC sequentially sends an impulse signal to the source lines.