Novel a-IGZO TFT Pixel Driving Circuit Using Hybrid PWM and PAM Method With Lower Power Consumption for Micro-LED Display

This letter reports a novel micro light-emitting diode (
$\mu $
LED) pixel driving circuit comprising ten amorphous indium gallium zinc oxide thin-film transistors (a-IGZO TFTs) and three capacitors. Hybrid PWM and PAM method is adopted to regulate gray-scales in the circuit using simple scan signals. Threshold voltage (Vth) shifts of TFTs are compensated in the pixel. To reduce the voltage drops caused by additional switching TFTs on the current path and save power, a matching TFT is used for the driving TFT Vth compensation. Simulation results indicate that the maximum error rates for emission time and current amplitude are -6.8% and 7.8% at a low gray level, respectively, under a Vth shift of 1 V. The power consumption of the circuit is successfully reduced thanks to the placement of only one TFT on the current path. Furthermore, we fabricated the pixel circuits which successfully demonstrates hybrid modulation.