Bidirectional Gate Driver Circuit Using Recharging and Time-Division Driving Scheme for In-Cell Touch LCDs

This paper proposes a new hydrogenated amorphous silicon thin-film-transistor-based (a-Si:H TFT-based) gate driver circuit that uses the time-division driving method to ameliorate the display-to-touch crosstalk. The proposed work utilizes a recharging circuit to discharge the voltage on the gate node of the driving TFT when the touch sensing starts with the purpose of suppressing the long-term stress of the driving TFT, and charges the gate node of the driving TFT again before the end of the touch-sensing period to enhance the driving capability of the gate driver circuit. Furthermore, the proposed gate driver circuit achieves bidirectional transmission and an adjustable reporting rate of touch sensing. Measurements verify that the threshold voltage shift of the driving TFT is suppressed from 4.8 to 2.9 V after 120 h of stress at 85 °C and the output waveforms of the proposed gate driver circuits are generated correctly with forward transmission, backward transmission, and pausing in different stages. Moreover, the measured output waveforms are stable without distortion after 360 h reliability test at 85 °C. Consequently, the proposed gate driver circuit is suitable for use in 5.46-in full high-definition panels with in-cell touch technology.