Robust low power DC-type shift register circuit capable of compensating threshold voltage shift of oxide TFTs

Abstract

This paper proposes an oxide TFT DC-type shift register that consists of eleven TFTs and one bootstrapping capacitor. The proposed circuit connects drain nodes of large size pull-up TFTs of output drivers to positive supply voltage instead of alternating clock signals for low power consumption. In addition, a robust internal inverter capable of maintaining the high voltage level of the output over the large positive threshold voltage shift by bootstrapping is implemented. For a 120Hz Full-HD display, the SPICE simulation estimates the clock power consumption of the proposed DC-type circuit as 0.56mW at 32 shift registers and ensures the robust operation over the wide range of threshold voltage shift from −4V to 10V.