An operating method of a display driving integrated circuit (DDIC) includes correcting first image data using correction data in a first operating mode. The first image data is received from a processor via an interface, and the correction data is stored in a first memory included in the DDIC. The method further includes storing second image data received from the processor in the first memory in response to a mode switching signal controlling the DDIC to switch to a second operating mode, and displaying the second image data on a display panel in the second operating mode.