A scalable 20 ×20 fully asynchronous SPAD-based imaging sensor with AER readout

In this paper we present a scalable 20×20 event-based imaging array. Each pixel consists of a large area (1200 μm
²
) single photon avalanche diode with dynamic quenching circuitry, compact 9-bit analog counter, comparator, and event generator. The array is designed for low-light imaging applications (<;0.1 lux) with a simulated worst case event readout speed of 33 MHz, pixel-level dynamic range of 134 dB, and array-level dynamic range of 132 dB. We implement this in a 0.50 μ m CMOS process with a 100 μm × 100 μm area pixel, a fill-factor of 20%, and a total chip size of 3 mm × 3 mm.