A Low Static-Power D Flip-Flop With Unipolar Thin Film Transistors on a Flexible Substrate

Abstract

There is increasing interest in affordable and flexible electronics, driven by the need for displays, conformable body sensors, and Internet-of-Things (IoT) gadgets. Amorphous silicon (a-Si:H), transition metal oxides, and organic thin-film transistors (TFTs) have demonstrated cost-effective large-scale production. As TFTs are typically unipolar in nature, they pose challenges for implementing CMOS-like circuits. Conventional methods to realize circuits in these technologies often lead to restricted voltage swing and excessive direct path current. While several methods have been proposed to counter the voltage swing issue, these methods fail to address the direct path current problem. This article presents low static-power D flip-flops (DFFs) using unipolar TFTs, which significantly reduces the direct path current. The proposed and conventional DFF designs were fabricated on a glass and flexible substrate using a-Si:H TFTs. Additionally, the impact of bending the flexible substrates was examined to assess the robustness and performance of the DFFs under mechanical strain. The measurement results show that the proposed design based DFF saves average total power by 79.8% compared to conventional design.