Provided is a display device including: a display panel; a system board configured to supply a signal and a voltage required to drive the display panel; a timing controller configured to receive the signal from the system board, generate control signals required to drive the display panel, and transmit some of the control signals to the system board; and a level shifter configured to convert voltage levels of the some signal of the timing controller into a signal voltage level suitable for the system board. The level shifter includes an output voltage control terminal configured to control the level shifter not to generate an output voltage when the system board is turned off.