A digital SiPM-based dTOF sensor with PDP optimization using configurable on-chip charge pump

A digital-SiPM based dTOF sensor with PDP optimization is proposed in this paper. The dTOF sensor consists of a configurable charge pump and a digital-SiPM including a 4×4 SPAD array. Exploiting a configurable charge pump, the bias voltage across the SPAD can be adjusted according to the background light intensity, hence optimizing the photon detection probability (PDP). The proposed dTOF sensor is designed in 110nm CIS process, with an active area of 555 μm × 638 μm. The post-layout simulation shows that the bias voltage can be adjusted from 16V to 20V. The maximum voltage drop caused by the avalanche current is 68 mV with all SPADs triggered simultaneous under various PVT conditions, and the 99 % recovery time for the output voltage is about 20 ns.