A Novel Level Shifter Employing IGZO TFT

Abstract

A new level shifter employing indium-gallium-zinc-oxide thin-film transistor (IGZO TFT) for a display panel was proposed and successfully fabricated. Two clock signals with 180° out of phase and a discharging TFT were employed to obtain a full-swing output. The IGZO level shifter has successfully exhibited a wide swing output from <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">VDD</i> to <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">VSS</i> without any additional power sources and input signals. The power consumption is 0.30 mW at a clock frequency of 12.5 kHz. The proposed level shifter with a depletion-mode device would be an important building block for an oxide TFT display.