A Three-Transistor Pixel Circuit to Compensate for Threshold Voltage Variations of LTPS TFTs for AMOLED Displays

This work presents a new pixel circuit adopting low-temperature polycrystalline-silicon thin-film transistors (LTPS TFTs) for active-matrix organic light-emitting diode (AMOLED) displays. The proposed pixel circuit can compensate for the threshold voltage variations of the LTPS TFTs with a simple structure. Simulated results demonstrate that the OLED currents over the entire data voltage range are uniform for ±0.5 V variations in the threshold voltage of the driving TFT, unlike in a conventional circuit. Furthermore, the relative current error rates for parasitic loads in the 1280 ×720 resolution AMOLED display are less than 6%.