Hydrogenated Amorphous Silicon Gate Driver With Low Leakage for Thin-Film Transistor Liquid Crystal Display Applications

Abstract

This paper presents a new low-leakage gate driver circuit using hydrogenated amorphous silicon (a-Si:H) thin-film transistors (TFTs) for active-matrix liquid crystal display (AMLCD) applications. The pull-down TFTs are turned OFF to maintain the high driving capability of the proposed circuit. Four phase clock signals with a duty ratio of 33% are utilized to turn ON the pull-down TFTs in advance to improve the stability of the row line at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{L}$ </tex-math></inline-formula> . The electrical characteristics of a fabricated a-Si:H TFT are measured to establish the model for HSPICE simulation to elucidate the effect of charge loss on the proposed circuit. Measurements confirm that the output waveforms of the proposed gate driver circuit remain identical to the initial waveforms and can be stabilized at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{L}$ </tex-math></inline-formula> at 85 °C over 720 h, ensuring the feasibility of the use of the proposed gate driver circuit in AMLCDs.