An AMOLED LTPS-TFT Pixel Circuit Using Mirror Structure to Compensate Vth Variation and Voltage Drop

摘要

A voltage programmed pixel circuit to compensate the threshold voltage variations of LTPS TFTs and the voltage drop at the power supply line is proposed, by extracting the threshold voltage of a mirror TFT adjacent to the driving transistor. The simulation results demonstrate that the relative current error rates are less than 5.3%, with the threshold voltage variations of ±0.5V and the voltage drop of -0.5V. Moreover, the contrast ratio is improved as light-emitting of the programming time is decreased.