A LTPS-TFT pixel circuit for active matrix organic light emitting diode based on improved current mirror

• Overcome the channel length modulation effect of TFTs.
• Support a stronger loading capability, which is importance to resist the non-uniform electrical characteristics of OLED pixels.
• Not only effectively compensates for non-idealities related with deviations of μ and VT in TFTs, the OLED degradation, but also offers a less setting time and guarantees a good liner relationship between VDATA and IOLED.
• Employ voltage driving and provide current compensation, taking advantages of current compensation and avoiding disadvantages of using constant current sources.

In this paper, a voltage-driving and current compensation method for active matrix organic light emitting diode (AMOLED) displays is proposed. An improved current mirror is introduced into the pixel circuit to overcome the channel length modulation effect of TFTs. The SPICE simulation results show that the proposed pixel circuit not only effectively compensates for non-idealities related with deviations of μ and VT in TFTs, the OLED degradation, but also offers a less setting time and guarantees a good liner relationship between VDATA and IOLED.