Disclosed are a power supply unit and a display device including the same, which prevent a source drive IC from being damaged by a supply reversal between a VDD voltage and an HVDD voltage. The power supply unit may include a first voltage generator that generates a first voltage and a first voltage line connected to the first voltage generator for supplying the first voltage to a plurality of first source drive ICs of the display panel. A second voltage generator is included that generates a second voltage, and a second voltage line is connected to the second voltage generator for supplying the second voltage to a plurality of second source drive ICs of the display panel. The power supply unit may further include a diode circuit that includes at least one diode connected between the first voltage line and the second voltage line.