A DC-DC converter for supplying a display panel with first and second power voltages, the DC-DC converter includes: a first converting module to convert an input power voltage into the first power voltage in response to a control signal; a sensor to detect a drive current of the display panel when the first power voltage is output; and a second converting module to convert the input power voltage into the second power voltage lower than the first power voltage in response to the control signal, the second converting module including: a first inverting converter to generate the second power voltage corresponding to the input power voltage regardless of an amount of the detected drive current; and a second inverting converter to selectively generate the second power voltage corresponding to the input power voltage and according to the amount of the detected drive current.