High-accuracy and compact quenching circuit for InGaAs SPADs

In 3D imaging application, large scale of SPAD arrays, low power consumption, compact and high accuracy quenching circuit is necessary. In this paper we developed a simple and fast pulse sensing circuit with negligible static power dissipation, and the afterpulsing effects are also significantly reduced by fast quenching process. The gated mode is used and it can precisely set the turn-off time of each frame. Ensure SPAD is more reliable. Compare to other active quenching circuits (AQC) for SPADs, the proposed circuit is ultra fast in signal pulse sensing and accurate in time resolution with a low threshold, and it can be easily utilized in SPAD-array detectors for photon-flight-time measurement with sub-nanosecond precision. The quenching circuit implemented by CSMC 0.5-μm CMOS technology is optimal designed by using SPICE simulator, where an accurate SPICE model we established for InGaAs SPAD is embedded. The simulation result shows that the proposed AQC can operate properly in all the static and transient states, and the rising time of the sensed voltage pulse can be caught in 1ns, and its quenching time is less than 5ns. This is much suitable for picosecond precision infrared sensing system.