A DC-DC converter includes a first converter outputting a first power voltage in a first driving method of generating an inductor current by alternately turning on transistors in a normal mode and outputting the first power voltage in a second driving method of generating the inductor current with the number of turn-on times less than that of the first driving method in a power saving mode, a second converter outputting a second power voltage in a third driving method of generating the inductor current with the number of turn-on times less than that of the second driving method in the power saving mode and determining differently magnitudes of the second power voltage in the power saving mode and the second power voltage in the normal mode, and a mode selector supplying a mode control signal to the converters to drive the converters according to one of the modes.