A display driver for driving a display panel includes a first driving circuit configured to output a first image signal to a first output pad, and a second driving circuit configured to output a second image signal to a second output pad; and the first driving circuit is further configured to output a reference image signal to the second driving circuit in response to a power down signal, and the second driving circuit is further configured to output the reference image signal output from the first driving circuit to the second output pad in response to the power down signal.