Design of Bidirectional and Highly Stable Integrated Hydrogenated Amorphous Silicon Gate Driver Circuits

Based on the use of a standard five-mask process, this work presents a new integrated hydrogenated amorphous silicon thin-film transistor (a-Si:H TFT) gate driver circuit for large size TFT-LCD applications, composed of a pull-up circuit with three TFTs, a pull-down circuit with ten TFTs, and two capacitors. The pull-up circuit, which separates the row line from the carry signal, prevents distortion of the output pulse. Moreover, the pull-down circuit with the AC-driving method can reduce the threshold voltage shift ( shift) to stabilize the output voltage and suppress the fluctuation of the row line, subsequently increasing the operating lifetime. According to accelerated lifetime test results, this gate driver circuit operates stably over 240 hours at 100°C. Additionally, the scan direction of the proposed circuit can be modified using two control signals and applied to the reversal display of an image.