A display panel includes input power supply line coupled to a power supply at one or more edge portions of the display panel, and an output power supply line coupled to the input power supply line at a predetermined portion of the display panel. The input power supply line receives the power supply voltage, and the output power supply line receives the power supply voltage from the input power supply line. The power supply is coupled to the output power supply line at the one or more edge portions of the display panel, and receives the power supply voltage from the output power supply line to adjust a voltage level of the power supply voltage based on the power supply voltage from the output power supply line. The predetermined portion is at a location different from an edge of the display panel.