A threshold voltage variation cancellation technique for analogue peripheral circuits of a display array using Poly-Si TFTs

Polysilicon thin-film technology has become of great interest due to the demand for large area electronic devices. Display applications, memories and optical copier are among the fields where polysilicon thin-film transistors (poly-Si TFTs) are most commonly used. However the design of analogue blocks, by using Poly-Si TFTs, with constant specifications is very difficult because of the large variation of the threshold voltage of the poly-Si TFT across the wafer and the kink effect makes. In this paper we propose a new circuit that can sense the voltage difference between two TFTs. This voltage can be used in order to design an improved current mirror with cancellation of threshold voltage variation.
QC 20111209