This paper demonstrates a novel low‐temperature‐poly‐Si thin‐film transistors (LTPS TFTs) gate driver with tunable width for low‐grey level brightness adjustment of active‐matrix organic light‐emitting diode (AMOLED) display. The width of output pulses can be tuned accordingly by changing the number of input pulses, to avoid changing the frequency, duty ratio, or increasing the numbers of the external clock‐lines. The proposed circuit still works well when outputting 10 ms pulse with leakage current above 1.45 nA.

et al. A gate driver circuit with two-stage pre-charge structure for in-cell touch panels (in Chinese).

A thin-film transistors (TFTs) integrated gate driver which can work well at low temperature down to -40 • C is proposed and demonstrated. The carry signal (CN) of the driver, being generated through the voltage bootstrapping approach using a CN-connected capacitor, is used to pre-charge the following stage of the driver. As the rising and falling time of CN is much shorter than that of the gate driving signal GN, the bootstrapping voltage is increased and voltage loss of the pre-charge transistor can be much reduced, to avoid the driver's malfunction at low temperature. This structure further benefits maintaining the driving speed over long operation time at high temperature. On the other hand, the GN, instead of CN, is used to reset the gate driver to suppress the voltage feed-through effects. One single stage of the driver consists of 11 TFTs and 2 capacitors, driven by 4 clock signals with the duty ratio of 25%. An a-Si:H TFTs implemented single stage circuit of the driver occupies an area of 250 μm×1099 μm. Measurements show that the output voltage magnitude can be maintained well when temperature varies from -40 • C to 80 • C. Moreover, the rising-time and falling-time increase of the output pulse are both less than 3 μs after 240 hours of the accelerated high temperature aging operations.INDEX TERMS a-Si TFT; gate driver circuit; reliability; low temperature

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In this work, we proposed a voltage‐programmed AMOLED pixel circuit using amorphous InGaZnO thin‐film transistors (a‐IGZO TFTs). For every display frame, thanks to the capacitive coupling method, the gate‐source voltage of the driving transistor is programmed through a zero to a positive value process, i.e. a unipolar sweeping direction is maintained for the driving transistor, to suppress the electrical hysteresis effects. In addition, the threshold voltage variation of the driving transistor can also be compensated through a source follower structure. Simulation results indicate that the relative current error is less than 30% for threshold voltage variations of ± 0.4 V.