Design Of Quenching Circuit For Geiger Mode Avalanche Photodiode

Avalanche photodiode operating in Geiger mode which is also called Single Photon Avalanche Diode(SPAD) has the advantage of fast response, small size, light weight, low power consumption and so on.SPAD has become the best device for high performance single photon detection system.Single photon detection technology is developing towards integration, miniaturization, array and high sensitivity.Quenching circuit as the interface circuit of SPAD detector and readout circuit plays a key role in the performance of single photon detection system.Under the limit of area and power consumption in large array SPAD readout circuit, a quenching circuit based on parasitic capacitance induction is proposed.The proposed circuit utilizes the parasitic capacitance of the SPAD to sense the avalanche current and simplifies the comparator stage with a single NMOS,which improves the sensing speed and reduce the area and power consumption of the circuit.Meanwhile,gate control mode is employed to accurately set the hold-off time,which improve the reliability of capacitance detection According to the non-uniformity of the breakdown voltage in SPAD array, this thesis designs a SPAD bias voltage regulate circuit which regulates the reset voltage of SPAD anode through the DAC output and reduces the effect of non-uniformity in breakdown voltage.Quenching circuit and bias voltage regulating circuit are simulated and fabricated using TSMC 0.35 μm CMOS process.The post simulation results indicate that the circuits can meet the design specification.The measurements of quenching circuit indicate that the circuit can work properly and preserves the advantages of fast reset(<3ns) and quenching(<3ns).Bias voltage regulation circuit operates properly and is able to regulate the anode voltage of SPAD.After adjusting the process drift of the resistance and under normal temperature, the measurements of voltage regulation range is 225mV-569mV and the adjustment number 2bit.