Single photon avalanche photodiode capacitance quenching circuit

Abstract

The invention relates to a single photon avalanche photodiode capacitance quenching circuit, and belongs to the technical field of semiconductor optoelectronics. According to the invention, junction capacitance of a single photon avalanche photodiode (SPAD), drain stray capacitance of a first NMOS transistor M1, grid stray capacitance of a second NMOS transistor M2 and grid stray capacitance of a first PMOS transistor M3 are utilized to act as load capacitance to sense avalanche current, introduction of high resistance is replaced, layout area is saved, the filling coefficient of a pixel unit is improved, and detection pixels of a detection array are effectively improved. The single photon avalanche photodiode capacitance quenching circuit is simple in circuit structure, a passive device does not exist, the avalanche current is sensed by only using the stray load capacitance at an anode point of the SPAD, I-Q-V integral conversion is performed, the current is converted into voltage signals, and pulse signals are outputted after the voltage signals are processed by an inverter. The structure can reduce the transient power consumption of the circuit on the one hand, and can accelerate the detection speed, shorten the quenching time, reduce the quantity of electric charge flowing through the SPAD on the other hand. In addition, the single photon avalanche photodiode capacitance quenching circuit is simple in circuit structure and conducive to large-scale array integration.

Description

Technical field [0001] The invention belongs to the technical field of semiconductor optoelectronics, and specifically provides a quenching circuit of a single-photon avalanche photodiode imaging device, which realizes the rapid quenching of the avalanche high current of the single-photon avalanche photodiode. Background technique [0002] Single-photon detection technology is a single-photon-based detection technology. Compared with the traditional imaging technology based on charge coupled device (ChargeCouple Device) and CMOS active pixel image sensor (CMOS Active Pixel Sensor), it has high detection sensitivity and response. Fast speed, strong anti-noise ability and easy large-scale array integration. It can be used in biochip detection, medical diagnosis, astronomical observation, quantum electronics and other fields, and it plays an increasingly important role. [0003] Single-photon detectors based on semiconductor avalanche photodiodes (Avalanche Photo Diode) are currently...

AI Technical Summary

Problems solved by technology

[0007] Aiming at the problems existing in the existing quenching circuit, the present invention provides a compact capacitive induction quenching circuit applied to the single photon avalanche photodiode, which uses the single photon avalanche photodiode SPAD junction capacitance and node parasitic capacitance to sense the avalanche current pulse , to avoid the problem of excessive layout area caused by the introduction of large resistors in the passive quenching circuit; secondly, ordinary quenching circuits that use transistors to induce avalanche current will change with the avalanche peak current of the single photon avalanche photodiode SPAD due to the load resistance , which greatly limits the scope of application of this type of avalanche circuit, and the capacitive quenching circuit can break through this limitation; in addition, the present invention uses capacitance to sense the avalanche current, avoiding the problem of excessive transient power consumption caused by the introduction of large resistance , can effectively reduce the overall power consumption, and the quiescent current is also smaller than that of ordinary resistance induction quenching circuits; finally, the present invention designs an adjustable time holding circuit according to the characteristics of different single photon avalanche photodiode SPAD, which increases the flexibility of the circuit Spend

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