Ambient light sensor circuit and flat panel display device having the same

摘要

Disclosed are an ambient light sensor circuit and a flat panel display device having the same that can automatically control screen brightness by sensing ambient brightness and controlling an output current. The ambient light sensor circuit comprises: a transistor electrically coupled to a first power source; a first capacitive element electrically coupled between a control electrode of the transistor and a first reference power source; a second capacitive element electrically coupled between the first capacitive element and a second reference power source; a first light receiving element electrically coupled between the first and third reference power sources and controlling a coupling voltage of the first capacitive element and charge/discharge voltages of the second capacitive element by conducting current in response to ambient light; a first switch electrically coupled to the transistor and enabling the transistor to output current from the first power source according to the coupling voltage of the first capacitive element; and a second switch electrically coupled between the first light receiving element and the first capacitive element and interrupting a leakage current of the first light receiving element, thereby preventing the coupling voltage of the first capacitive element from being changed.