A power supply unit adapted to prevent or reduce damage to devices when the devices receive power with an abnormal voltage, and an organic light emitting display device using the same. An embodiment of the present invention provides a power supply unit, including: a power block including an input terminal for receiving an input power, an output terminal for outputting an output power, and an enable terminal for receiving an enable signal for controlling a driving of the power block; an input power unit configured to concurrently transfer the input power to the input terminal and the enable terminal; and a controller configured to control a voltage of the input power transferred to the enable terminal to determine the driving time point of the power block, and an organic light emitting display device using the same.