Patent ID: 6433488
Filing Date: 2002-08-13
Classification: G09G

Abstract:
An organic light emitting diode active driving system with current feedback for driving an organic light emitting diode, comprising:a first transistor having a current carrying electrode connected to a cathode of said organic light emitting diode, a current carrying electrode connected to ground, and a gate electrode; a second transistor having a current carrying electrode connected to a gate electrode of said first transistor, a current carrying electrode as a data signal input terminal, and a gate electrode as a scan signal input terminal; a capacitor connected between said gate electrode of said first transistor and ground as a storage element; a current comparator having two comparison terminals and an output terminal connected to said data signal input terminal; a third transistor having a current carrying electrode connected to an anode of said organic light emitting diode, a current carrying electrode connected to a comparison terminal of said current comparator, and a gate electrode connected to said scan signal input terminal; and a fourth transistor having a current carrying electrode connected to an anode of said organic light emitting diode, a current carrying electrode connected to a first supply voltage, and a gate electrode for receiving a reverse signal of said scan signal input terminal; wherein said two comparison terminals of said current comparator respectively receive a reference current with a predetermined value and a driving current flowing through said organic light emitting diode, compare said reference current and said driving current, and output a voltage to said data input terminal in response to a comparison result, so that the value of said driving current equals to that of said reference current.