A Pull-Up Adaptive Sense Amplifier Based on Dual-Gate IGZO TFTs

Abstract

Thin-film transistor (TFT) not only is the backbone of display technology, but also brings in fancy applications in the area of flexible electronics. TFT-based flexible circuit design however faces various challenges, such as unipolar devices and severe nonuniformity. In this paper, a sense amplifier based on dual-gate indium-gallium-zinc oxide (IGZO) TFTs is proposed for TFT-based static random access memory (SRAM) circuits. The pull-up transistors in the proposed sense amplifier are implemented with dual-gate TFTs while the pull-down transistors are implemented with conventional bottom-gate TFTs. By tuning the top gate of the pull-up transistors to achieve a negative threshold voltage as well as employing a specialized strength- adaptive pull-up structure, the proposed sense amplifier aims to reduce the offset voltage, sensing delay, and sensing power consumption simultaneously. Compared to the state-of-the-art IGZO-based sense amplifier, the proposed sense amplifier achieves up to 66.1% lower offset voltage, 68.9% shorter sensing delay, 72% dynamic power savings, and 66.3% leakage power savings.