No Static Power Excess Bias Voltage Monitoring Circuit (EBVMC) for SPAD Applications

A design for monitoring the excess bias voltage of the Single Photon Avalanche Diode (SPAD) is described in this paper. Due to being a mostly digital solution without static power consumption, the presented approach makes it suitable for low power system applications. The core of the new concept uses a latched comparator incorporated with a passive quenching circuit. The algorithm and a system for calibration and monitoring the excess bias voltage are also described. The resolution of controlling the excess bias voltage is equal to a charge pump voltage step. The circuit is designed in 55nm CMOS technology.