Inverters Using Only N-Type Indium Gallium Zinc Oxide Thin Film Transistors for Flat Panel Display Applications

Two inverter architectures are proposed to be integrated on panels for flat panel display applications using only n-type amorphous indium gallium zinc oxide (IGZO) thin film transistors (TFTs). The proposed cross-coupled (CC) inverter uses the positive feedback effect of its CC structure to reduce the static current and increase the output voltage swing when using depletion mode n-type amorphous IGZO TFTs. The other proposed cross-coupled and bootstrapping (CCB) inverter also uses the cross-coupled structure and includes a capacitor for the bootstrapping effect to increase the operating frequency. The measured results show that the output voltage swing of the proposed CC inverter is from 0 to 14.50 V and that of the CCB inverter is from 0.15 to 14.57 V when V DD is 15 V at 20 kHz and the load capacitance is 103.0 pF. The power consumption of the CC and CCB inverters are 1.4 and 2.5 mW, respectively, which are 29.3 and 53.4% of the power consumption of the ratioed inverter.