The present invention relates to a method for properly controlling the drive current when driving an Active Matrix OLED (AMOLED) in order to prevent the brightness from being changed due to temperature changes in a panel or the performance deterioration of the OLED. The present invention comprises: an OLED (organic light emitting diode) panel that displays an image; pixel driving circuit including: a drive current control unit that outputs a current control signal corresponding to a detected current supplied to the OLED panel; and a comparator that compares the current control signal with a power supply voltage and outputs a bias voltage; and a transistor that receives the power supply voltage and that supplies a drive current to the OLED panel corresponding to the bias voltage.