Event Detection Pixel Sensor (EDPS) Circuit Using Phase Transition Material

An event detection image sensor captures only changes in a scene by detecting variations in light intensity at each pixel, enabling high-speed, low-power, and low-latency imaging [1]. This is essential for applications like robotics, autonomous vehicles, and surveillance, where rapid response to dynamic scenes is critical [1]. Phase transition materials (PTMs) have demonstrated significant potential for various applications, including enhancing memory read operations, designing neurons, oscillators, and contrast enhancement circuits [2]. A Phase-Transition Material (PTM) undergoes an insulator-to-metal transition (IMT) at a critical voltage ($\mathrm{V}_{\text {C-Imt }}$) / current ($\mathrm{I}_{\text {C-Imt }}$) and reverts via a metal-to-insulator transition (MIT) at $V_{\text {C-MIT }} / I_{\text {C-MIT }}$ (Fig. 1(a)). When integrated into the source of a Field-Effect Transistor (FET), it forms a HyperFET (Fig. 1(b), (c)) [3]. It switches states at critical gate-to-source voltages ($\left|\mathrm{V}_{\mathrm{GS}-\mathrm{IMT}}\right|$ and $\left|\mathrm{V}_{\mathrm{GS}-\mathrm{MIT}}\right|$) (Fig. 1(d)). In this work, we leverage PTM’s abrupt switching behavior to design a compact event detection pixel sensor circuit using efficient thresholding, while other existing designs rely on areahungry comparators [1], [4], [5]. Our circuit’s thresholding is tunable in both design phase and real time.