N-Type Low-Temperature Polycrystalline Silicon and Amorphous Oxide Thin-Film Transistor-Based Robust Dual-Output Gate Driver

Abstract

This work presents a dual-output gate driver that is based on low-temperature polycrystalline silicon and amorphous oxide (LTPO) thin-film transistors (TFTs) and supports bidirectional transmission. This gate driver generates positive and negative pulses for both n-type and p-type switching TFTs in display pixels, effectively reducing the bezel area. Simulation results indicate that the output waveforms remain undistorted even when the threshold voltage ( ${V}_{\text {TH}}$ ) of low-temperature polycrystalline silicon (LTPS) TFTs varies by ±0.46 V and the ${V}_{\text {TH}}$ of the amorphous indium gallium zinc oxide (a-IGZO) TFTs shifts by +0.56 V. This gate driver achieves short rising/falling times of approximately 1.25/ $1.42~\mu $ s for a positive pulse and 1.55/ $2.73~\mu $ s for a negative pulse through the output circuit composed of LTPS TFTs during forward transmissions. When operated at 1 Hz, the output waveforms are correctly generated and stabilized at +6.6 V and −6.6 by the stabilization circuit, which includes a-IGZO TFTs. Therefore, the proposed gate driver is promising for use in low-frame-rate smartwatch displays.