A charge-pump-based current feedback method for amoled displays

This work presents a new external driving scheme that uses the current feedback method with a 3T1C pixel circuit. The proposed circuit provides a stable OLED driving current by compensating for the threshold voltage shift of amorphous-silicon thin-film transistors (a-Si TFTs). For fabricated a-Si TFTs and the 0.35 μ m CMOS process associated with the proposed driving scheme, measurements reveal that the normalized OLED current degradation is less than 5% after 60 hours of operation at 60 °C. Moreover, for a data line load of 1.69 KΩ110 pF, the relative error rates between data currents and OLED currents are less than 4% within a settling time of 19. μm