Efficient Driver Design for Amoled Displays

The conventional A current feedback driver with double zeros compensation is proposed for medium to large AMOLED displays. The zeros for lead compensation are implemented with switched-capacitor circuits to reduce chip area. The selection rules for compensation Capacitors and zero capacitors are described to obtain wide bandwidth and high speed. The proposed driver has a settling time of 7us for the panel load of 10k/100pF. This work uses high gain and low gain differential amplifiers to provide constant current through pixel and also make sure that voltage induced in capacitor will keep transistor in saturation to make further operation in emission period. Capacitors used for this feedback loop will provide high speed and high bandwidth. Two phases of operation is done to make current through pixel is constant. The feedback system can be analyzed to check performance by parameters like gain margin and phase margin. This current feedback system gain margin and phase margin can be calculated by keeping Data current initially zero and testing output using test voltage. OTRA, high slew rate TRA are used to improve GM, PM with current feedback. In this paper all feedback techniques are compared by checking their performances based on gain margin and phase margin.