A 48×2 CMOS SPAD Sensor With Regulated Dark Count

This brief presents a dark count regulation technique for CMOS SPAD array sensor. Proposed global/local dual biasing scheme allows setting an individual excess bias for each SPAD. The column shared calibration block compares each pixel's dark count to a target count value to control the local bias voltage of that pixel. The 48×2 SPAD sensor chip is implemented in a 0.18 μm BCD CMOS process and the proposed technique improves the dark count uniformity by ×2.6. We also demonstrated the linear control of photon detection efficiency as well as the average dark count of the sensor.