IGZO TFT Gate Driver Circuit With Improved Output Pulse

• Published in: IEEE journal of the Electron Devices Society Vol. 7; pp. 309 - 314
• Main Authors: Kim, Jin-Ho, Oh, Jongsu, Park, Keechan, Jeon, Jae-Hong, Kim, Yong-Sang
• Format: Journal Article
• Language: English
• Published: New York IEEE 2019; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: a-IGZO TFTs; Couplings; Depletion; depletion mode; Driver circuits; Gallium; gate driver circuit; Gate drivers; Gates (circuits); Indium gallium zinc oxide; Leakage current; Leakage currents; Low voltage; output pulse; peak voltage; Power consumption; Power demand; pull-down transistor; Pulse duration; Semiconductor devices; Thin film transistors; Threshold voltage; Transistors; Voltage drop; Zinc oxide
• ISSN: 2168-6734; 2168-6734
• DOI: 10.1109/JEDS.2018.2884920

We propose a new gate driver circuit with an improved output pulse using depletion mode amorphous indium gallium zinc oxide thin film transistors. The previous reported gate driver circuit of our group has a weak point. It is that the peak voltage of the output pulse is decreased during the output pulse duration. A peak voltage drop of output pulse is larger by an increase the leakage current of the pull-down transistor as an increase of the threshold voltage (Vth) in the negative direction. Also, a power consumption is increase by that. In this paper, the new gate driver circuit is proposed to solve this weak point. The peak voltage drop of the output pulse of the new gate driver circuit is not occurred as an increase of the pull-down transistor Vth in the negative direction. The peak voltage of the output pulse of the previous reported circuit is 27.5 and 26.2 V at the transistor Vth of 0.5 and -2.9 V, respectively. However, the peak voltage of the output pulse of the new gate driver circuit is 27.8 and 27.6 V at the transistor Vth of 0.5 and -2.9 V, respectively.