A new analog buffer using P-type poly-Si TFTs for active matrix displays

A new simple analog buffer employing p-type low-temperature poly-Si thin-film transistors (TFTs) are proposed and fabricated for the integrated data driving circuits of AMLCD and AMOLED. The new analog buffer does not use any capacitors to store the threshold voltage of a poly-Si TFT, so that it could reduce the output offset by the subthreshold current of poly-Si TFT. The simulation and experimental result exhibit that the buffer output successfully charges the buffer load (∼20 pF) to the input value quickly by the boot-strapping. The measured output offset voltages are less than ±70 mV when the input varies from 1 to 10 V.