Gate driver with low‐temperature polycrystalline silicon and oxide thin‐film‐transistor circuits for low power consumption and narrow bezel AMOLED displays

Abstract

AbstractWe propose a novel gate driver circuit using low‐temperature polycrystalline silicon and oxide (LTPO) thin‐film transistors (TFTs). The proposed circuit consists of only six TFTs, four p‐type LTPS, and two n‐type a‐IGZO TFTs, without capacitor. The proposed circuit operates well when oxide TFTs have threshold voltage (VTH) of −7.5 V, which is very depletion mode. Without bootstrapping, low gate bias stress occurs on TFTs in the proposed circuit. With dual gate (DG) structure of oxide TFTs, the stability of the proposed circuit is improved. In addition, by utilizing extremely low off‐state current of oxide TFTs, ultra‐low power consumption can be achieved. The total power consumption of the proposed gate driver is less than 100 mW under a‐IGZO TFT's VTH of −6 V at 120 Hz 4k (3,840 × 2,160) resolution display. The fabricated circuit works perfectly at a pulse width of 1 μs equivalent to operating speed of 500 kHz. The proposed circuit can be applied to ultra‐high definition (UHD) and narrow bezel AMOLED display.