Design of a Low-Voltage and Reduced Programming cycle AMOLED Pixel Circuit using IGZO TFTs

This work presents a 5T −2C pixel circuit based on amorphous indium gallium zinc oxide (a-IGZO) thin film transistors (TFTs) for flexible displays utilizing improved stacked voltage-programmed pixel circuit topology. Due to a low operating voltage of 5 V and reduced programming time of 8
$\mu\mathrm{s}$
, the proposed circuit finds its application in large screen HD displays as it can provide a very high frame rate of 120 Hz. Moreover, a good compensation ability of the proposed circuit against the threshold voltage variations of the driving TFT in the range of −0.2 volts to 2 volts from the nominal voltage of 0.7 volts, makes it suitable for flexible AMOLED displays. The error in organic light emitting diode (OLE D) current is within 0.4% over the range of data voltage (3.8 V to 6 V) when the substrate is subjected to both compressive and tensile strains of
$\pm 0.3$
% and within 10% due to threshold voltage variations under electrical stress. The adapted SPICE level-3 flexible TFT model efficiently captures the variations in threshold voltage due to mechanical as well as electrical stress. As a result, the proposed 5
$T$
2C pixel circuit reveals good performance for applications in low-voltage flexible displays.