In one embodiment of the present invention, a liquid crystal driving semiconductor IC for driving a display panel includes an output terminal connected to the display panel, an output circuit block including a DAC circuit, and a spare output block including a DAC circuit, the DAC circuits and being connectable to the output terminal. The IC includes an op amp for comparing output signal from the DAC circuit with that of the DAC circuit, and judging circuit for judging, based on the comparison result of the op amp, whether the DAC circuit is defective, and switches and for, if the DAC circuit is defective, connecting the spare DAC circuit to the output terminal in replacement of the defective DAC circuit. This provides an IC for driving a display device, which IC has concrete measures to easily detect a defect in an output circuit, and can perform self-healing for the defect in the output circuit.