Time-analog switching circuit and single photon flight time measuring method

Abstract

The invention discloses a time-analog switching circuit and a single photon flight time measuring method. The time-analog switching circuit comprises a signal input logic unit, a timing unit, a voltage holding unit and a read out unit; the signal input logic unit converts a photon signal into a logic electrical level, and the input end of the signal input logic unit correspondingly receives the photon signal, a start signal and a stop signal, and the output end of the signal input logic unit is connected with the input end of the timing unit; the timing unit includes a current mirror structureproviding a stable charging current, a current mirror structure providing a current source and a timing capacitor, and a voltage of an electrode plate of the timing capacitor linearly increases withtime after the timing capacitor starts counting; the voltage holding unit is used for holding the voltage of the electrode plate of the timing capacitor, the input end of the voltage holding unit is connected with the output end of the timing unit, the output end of the voltage holding unit is connected with the read out unit, and the read out unit reads out a voltage signal of the electrode plate. According to the time-analog switching circuit and the single photon flight time measuring method, the manufacturing process is compatible with the CMOS process, the manufacturing cost is low, and the rate of finished products is high; and meanwhile, the time-analog switching circuit has the advantages of high filling factors, high resolution and a large measuring range.

Description

technical field [0001] The invention relates to a time-analog conversion circuit for measuring single-photon time-of-flight (TOF) and a method for measuring TOF by the circuit, in particular to a single-photon time-of-flight detection circuit and measurement method based on a Wilson current source. Background technique [0002] Single-Photon Avalanche Diode (SPAD) has significant advantages such as large avalanche gain, fast response speed, high detection efficiency, low cost, and low power consumption. It has broad application prospects in detection, laser ranging, 3D imaging, etc. These application areas all require photon time-of-flight (TOF) measurement to obtain time-correlated single-photon counting / timing results. The methods for measuring the time of flight of photons mainly include time-to-digital conversion circuit TDC and time-to-analog conversion circuit TAC. [0003] The detection time of TDC is affected by the time resolution. As the detection distance increa...

AI Technical Summary

Problems solved by technology

However, the time measurement range of traditional TAC circuits is short, usually from a few nanoseconds to tens of nanoseconds, so the distance that can be measured is small

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