An organic light emitting display device and a power supply for the same. In one embodiment, an organic light emitting display device includes a first module and a second module, each including an organic light emitting display panel and a driving source. A power supply is for supplying a first driving voltage to the first module and a second driving voltage to the second module. A controller is for applying a common control signal and a data signal to the first module and the second module and for applying a selection signal for selecting at least one of the first module or the second module.