Quenching and readout circuits for single photon avalanche diodes

Abstract

The invention relates to a quenching and reading circuit for a single photon avalanche diode. The circuit comprises two achieving forms which both comprise the single photon avalanche diode and three NMOS (N-Mental-Oxide-Semiconductor) tubes. According to the a first embodiment, the quenching and reading circuit for the single photon avalanche diode comprises a first single photon avalanche diode, a first NMOS tube, a second NMOS tube and a third NMOS tube; a negative electrode of the first single photon avalanche diode is connected with a positive high pressure bias power source; a positive electrode of the first single photon avalanche diode is connected with a grid electrode of the first NMOS tube and a drain electrode of the second NMOS tube; a source electrode of the first NMOS tube and a source electrode of the second NMOS tube are connected with the ground; a grid electrode of the second NMOS tube is connected with a pulse signal; a source electrode of the third NMOS tube is connected with a drain electrode of the first NMOS tube; a grid electrode of the third NMOS tube is connected with a decoded signal; a drain electrode of the third NMOS tube is connected with a digit line. The quenching and reading circuit for the single photon avalanche diode has the advantages of being simple in structure, beneficial to system integration, rapid in response speed, high in detection accuracy, flexible and adjustable, stable and reliable and the like.

Description

technical field [0001] The invention relates to the technical field of extremely weak light signal detection, in particular to a single photon avalanche diode (Single Photon Avalanche Diode, SPAD) quenching and readout circuit. Background technique [0002] In the fields of biomedicine, quantum imaging, laser measurement, encryption systems, and environmental radiation detection, it is often necessary to identify and extract the desired signal under adverse conditions where the noise is far greater than the useful signal. Technology places increasingly demanding demands. Single-photon detection technology has the advantages of ultra-high sensitivity and ultra-fast response speed. It can detect the smallest energy particle of light—photon. It is currently a relatively mature method for detecting extremely weak light. The energy of a single photon is extremely small, only 10 -19 ~10 -18 J, in order to detect single photons, special optoelectronic devices must be used. The ...

AI Technical Summary

Problems solved by technology

It takes a certain amount of time for the quenching circuit to completely quench the avalanche and restore it to its original state, that is, the dead time. If the dead time is too long, it will limit the maximum counting rate of the detector.

[0016] (2) Low precision

When no photons arrive, various noises will also cause SPAD to avalanche and output avalanche electric pulses, resulting in dark counting. In addition, the carriers captured when photons arrive in avalanche will also be quenched in a strong electric field due to untimely quenching. Under the action and then released to cause after-pulse, these will cause the detector to miscount and affect the detection accuracy

[0017] (3) Poor reliability

If no photons arrive, the SPAD will work under strong reverse bias for a long time, and it is easy to damage the detector

[0018] (4) Large power consumption and area

Traditional quenching circuits generally use large-sized MOS tubes or large resistors to increase the quenching speed, and sometimes there are large capacitors, which consume large power and increase the layout size of the unit, which is not conducive to system integration

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