A display device includes a first power source, a timing controller, and pixels. The timing controller is connected to the first power source through a main line, an auxiliary line, and a detection line. The pixels are commonly connected to the first power source through a first power line. The first power source includes: a main power source connected to the first power line and the main line; an auxiliary power source connected to the auxiliary line; a rectifier connected between the auxiliary power source and the first power line; and a comparator comparing a voltage of the first power line and providing its output to the detection line.