Single-photon ranging laser radar receiving device and control method
By using the SPAD array and the multi-hit TDC module in the lidar receiving device, directly storing the TOF information of the last event, the problem of collecting histograms and repeatedly storing data in the prior art is solved, and the scene acquisition rate of the lidar is improved.
Patent Information
- Application Number
- CN202510097143.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-21
- Publication Date
- 2025-04-15
AI Technical Summary
The prior art requires collecting histograms, and the laser repeats at the same point in the scene, and more TOF data is needed for each frame, resulting in a slower scene acquisition rate of the lidar.
A single-photon ranging lidar receiving device is provided, including a SPAD array, a SPAD quenching circuit, a current generator, a transimpedance amplifier, a peak holder, an AC coupling circuit, a comparator and a multi-hit TDC module. Through the coordinated work of these components, the TOF information of the last event is directly stored, avoiding collection of histograms and repeated storage.
It realizes working in a single shot state, without the need to collect histograms and store unnecessary TOF data, and improves the scene acquisition rate of lidar.
Smart Images
Figure CN119828156A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of single-photon ranging, and in particular to a single-photon ranging laser radar receiving device and a control method. Background Art
[0002] The LiDAR system uses the Time Of Flight (TOF) technology to estimate the distance of the target object by accurately measuring the time delay from the laser pulse being emitted to the target reflecting and returning, and is particularly good at long-distance measurement. In Direct TOF applications, the system emits a pulsed laser to the target, and then the photodetector captures the reflected light and activates the Time Digital Converter (TDC) to quantify the laser round-trip time difference.
[0003] LiDAR often uses a pulsed laser mode, and each detector pixel independently calculates the TOF of its own illumination point. Although flash LiDAR can theoretically capture the whole picture in a single pulse, its high energy requirements limit its effective range in high background noise environments to no more than a few dozen meters due to eye safety standards. In contrast, scanning LiDAR can achieve longer distance measurement, although its field of view is narrower and its frame rate is limited by the scanning speed.
[0004] In the field of advanced driver assistance systems (ADAS) and autonomous driving, LiDAR needs to quickly build a high-precision (centimeter-level) 3D environmental model covering hundreds of meters, while requiring low-latency processing. Faced with challenges such as laser echo attenuation with the square of the distance, large differences in target reflectivity, and strong background light, the detector needs to have a wide dynamic range capability.
[0005] In recent years, single-photon avalanche diodes (SPADs) have gradually become the preferred choice for LiDAR detectors due to their high sensitivity. Silicon-based SPADs (operating up to 1000nm wavelength) can operate at room temperature, have a low dark count rate (DCR) and are easy to integrate with on-chip electronic systems to achieve efficient TOF measurement and data processing. InGaAs / InP SPADs extend the sensitivity to 1.7μm, but are accompanied by high DCR and require cooling. However, the inherent dead time of SPADs (tens of nanoseconds for silicon-based and microseconds for InGaAs) limits its maximum photon detection rate, and it is impossible to distinguish between single-photon and multi-photon events, so it is necessary to control the trigger probability to avoid "detector pile-up", especially under high background light conditions. Increasing the optical aperture and the number of SPADs in the pixel becomes an effective strategy.
[0006] In view of the stray triggering caused by DCR and background light, a single TOF measurement is not enough to accurately determine the target distance. Therefore, multiple laser pulse emission and TOF acquisition strategies are often used to construct a TOF histogram. Among them, the highest peak corresponds to the effective laser echo, while the lower peak may come from multiple reflections, and the baseline reflects the random distribution of DCR and background photons. In order to deal with the "electron pile-up" problem, that is, the information loss and histogram distortion caused by only recording the first TOF event in a single pulse, a multi-hit TDC and memory are required in a high-noise environment to ensure that each pulse can capture and store multiple TOF data points to ensure the accuracy and reliability of the measurement. However, this solution requires the collection of histograms, and the laser is repeated at the same point in the scene, and more TOF data needs to be stored in each frame, resulting in a slow scene acquisition rate for the lidar. Summary of the invention
[0007] The purpose of the embodiments of the present application is to provide a single-photon ranging laser radar receiving device and control method to solve the problem that the prior art needs to collect histograms, and the laser repeats at the same point of the scene, and each frame also needs to store more TOF data, resulting in a slow scene acquisition rate of the laser radar.
[0008] A single-photon ranging laser radar receiving device provided in an embodiment of the present application includes: a SPAD array, a SPAD quenching circuit, a current generator, a transimpedance amplifier, a peak holder, an AC coupling circuit, a comparator, and a multi-hit TDC module;
[0009] The SPAD array is used to receive optical signals and generate avalanche current;
[0010] The SPAD quenching circuit is used to quench the avalanche current and generate a first pulse signal;
[0011] The current generator is used for converting the first pulse signal into a current signal;
[0012] The transimpedance amplifier is used to convert the current signal into a voltage waveform signal;
[0013] The peak holder is used to detect and hold the peak value of the voltage waveform signal to obtain a shaped signal;
[0014] The AC coupling circuit is used to remove the DC component of the shaped signal to obtain a second pulse signal;
[0015] The comparator is used for converting the second pulse signal into a digital pulse according to a set threshold value;
[0016] The multi-hit TDC module is used to trigger the hit TDC multiple times according to the digital pulse to obtain multiple TOFs; the TOF of the last event is used as the final distance information.
[0017] In the above technical solution, the first pulse signal generated by the SPAD quenching circuit is converted into a voltage waveform signal after passing through the current generator and the transimpedance amplifier. The peak holder monitors and tracks the highest peak detected to obtain the shaped signal. The AC coupling circuit tracks the derivative of the shaped signal. The comparator triggers the multi-hit TDC to store TOF information. At the end of the frame (before the next laser shot), the only stored TOF value is the TOF of the last event, that is, the highest signal peak detected in the current frame. This solution does not need to collect histograms, does not need to store more TOF data per frame, and does not need to perform post-processing. It can work in a single-shot state to avoid laser repetition at the same point in the scene, thereby improving the scene acquisition rate of scanning single-point laser radar.
[0018] In some optional implementations, it also includes: a gating module; the gating module is used to filter out the avalanche current outside the gating period of the first pulse signal, retain the avalanche current within the gating period, and obtain a third pulse signal.
[0019] In the above technical solution, the core function of the gating module is that it only allows avalanche currents within a specific gating period to pass through, and filters out all avalanche currents outside the gating period. This mechanism directly reduces false triggering events caused by the detector's own noise (such as dark counts), thereby significantly reducing DCR and improving the signal-to-noise ratio. The gating module can also effectively reduce other types of background noise interference. Because the avalanche currents generated by background light and other non-target signals are mostly not within the preset gating period, these noise signals will be effectively shielded by the gating module, thereby improving the anti-noise ability of the entire system. By reducing noise interference and DCR, the gating module enables the system to more accurately identify and record valid TOF data. This helps to improve the accuracy and reliability of ranging in complex environments (such as high background noise, multiple reflections, etc.). The gating time of the gating module can be adjusted by an external or internal trigger, and the user can flexibly set the width and frequency of the gating according to the needs of the actual application scenario. This configurability enables the receiving device to adapt to different ranging tasks and environmental conditions, improving the flexibility and applicability of the system.
[0020] In some optional embodiments, it also includes: a random event filter; the random event filter is used to filter out random SPAD trigger events within the gating period of the third pulse signal, retain the real SPAD events related to time, and obtain a fourth pulse signal.
[0021] In the above technical solution, the random event filter is a configurable SPAD event filter, which is composed of several interconnected logic AND gates and OR gates; since the SPAD events triggered by noise are random, while the real SPAD events are time-related, the random event filter can filter out the random SPAD triggering events during the gated period and retain the real SPAD events. Furthermore, some of the SPADs can be selected for random event filtering, thereby increasing accuracy and flexibility, and further increasing precision.
[0022] In some optional embodiments, a current buffer is further included; the current buffer is used to transmit the fourth pulse signal from an input source with extremely small impedance to an output load with high impedance to obtain a fifth pulse signal;
[0023] The current generator is used for converting the fifth pulse signal into a current signal.
[0024] In the above technical solution, the main function of the current buffer is to transmit the signal from an input source with extremely small impedance (such as the fourth pulse signal output by the random event filter) to an output load with high impedance without introducing significant signal attenuation or distortion. This ensures the integrity and quality of the signal and reduces the signal loss caused by impedance mismatch during signal transmission. The current buffer usually has a higher current gain and bandwidth, which can enhance the driving capability of the signal, so that the signal can be transmitted to the subsequent processing circuit or device more stably and reliably. This is especially important for lidar receiving devices that require high sensitivity and high-speed response.
[0025] In some optional implementations, a plurality of SPAD arrays are included, each SPAD array corresponds to a SPAD quenching circuit, a gating module, a random event filter, and a current buffer:
[0026] The outputs of the multiple current buffers are coupled and then output to the current generator.
[0027] In the above technical solution, multiple SPAD arrays are connected in parallel to aggregate photon detection events, reducing the impact of background noise and saturation. In addition, the outputs of multiple current buffers are coupled and output to the current generator. Due to the effect of the current buffer, the input source with extremely small impedance (effective resistance) is transmitted to the output load with high impedance, preventing the signal source from being affected by any difference in the amount of current absorbed by the output load, so as to aggregate the output currents of the two groups of SPAD arrays, reduce current loss, and output to the current generator.
[0028] A control method for a single-photon ranging laser radar receiving device provided in an embodiment of the present application includes:
[0029] Using SPAD array, light signals are received and avalanche current is generated;
[0030] Using a SPAD quenching circuit to quench the avalanche current and generate a first pulse signal;
[0031] Using a current generator, converting the first pulse signal into a current signal;
[0032] Using a transimpedance amplifier, the current signal is converted into a voltage waveform signal;
[0033] The peak value of the voltage waveform signal is detected and held by using a peak holder to obtain a shaped signal;
[0034] Using an AC coupling circuit, the DC component of the shaped signal is removed to obtain a second pulse signal;
[0035] Using a comparator, converting the second pulse signal into a digital pulse according to a set threshold value;
[0036] Using the multi-hit TDC module, the TDC is triggered multiple times according to the digital pulse to obtain multiple TOFs; the TOF of the last event is used as the final distance information.
[0037] In some optional embodiments, the method further comprises:
[0038] The gate control module is used to filter out the avalanche current outside the gate control period of the first pulse signal, and retain the avalanche current within the gate control period to obtain a third pulse signal.
[0039] In some optional embodiments, the method further comprises:
[0040] The random event filter is used to filter out the random SPAD triggering events within the gated period of the third pulse signal, retain the real SPAD events related to time, and obtain the fourth pulse signal.
[0041] In some optional embodiments, the method further comprises:
[0042] A current buffer is used to transmit the fourth pulse signal from an input source with extremely small impedance to an output load with high impedance, so as to obtain a fifth pulse signal;
[0043] The fifth pulse signal is converted into a current signal by using a current generator.
[0044] In some optional embodiments, the method further comprises:
[0045] The avalanche current generated by each SPAD array is processed in sequence by the corresponding SPAD quenching circuit, gating module, random event filter, and current buffer;
[0046] The outputs of the plurality of current buffers are coupled and then output to the current generator. BRIEF DESCRIPTION OF THE DRAWINGS
[0047] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.
[0048] Figure 1 A functional module diagram of a single-photon ranging laser radar receiving device provided in an embodiment of the present application;
[0049] Figure 2 A SPAD trigger event waveform diagram provided in an embodiment of the present application;
[0050] Figure 3 The peak holder output waveform diagram provided in the embodiment of the present application;
[0051] Figure 4 Output waveform diagram of the AC coupling circuit provided in the embodiment of the present application;
[0052] Figure 5 A comparator output waveform diagram provided in an embodiment of the present application;
[0053] Figure 6 A flowchart of the single-photon ranging laser radar receiving device provided in an embodiment of the present application;
[0054] Figure 7 A schematic diagram of a non-gated mode and a gated mode provided in an embodiment of the present application;
[0055] Figure 8 A schematic diagram of a random SPAD triggering event and a real SPAD triggering event provided in an embodiment of the present application;
[0056] Fig. 9 A flow chart of the steps of a control method for a single-photon ranging laser radar receiving device provided in an embodiment of the present application. DETAILED DESCRIPTION
[0057] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.
[0058] Please refer to Figure 1 , Figure 1A functional module diagram of a single-photon ranging laser radar receiving device provided in an embodiment of the present application includes: a SPAD array, a SPAD quenching circuit, a current generator, a transimpedance amplifier, a peak holder, an AC coupling circuit, a comparator and a multi-hit TDC module; the SPAD array is used to receive optical signals and generate avalanche current; the SPAD quenching circuit is used to quench the avalanche current and generate a first pulse signal; wherein each SPAD and its quenching circuit constitute a micro unit; the current generator is used to convert the first pulse signal into a current signal; the transimpedance amplifier is used to convert the current signal into a voltage waveform signal; the peak holder is used to detect the peak value of the voltage waveform signal and hold it to obtain a shaped signal; the AC coupling circuit is used to remove the DC component of the shaped signal to obtain a second pulse signal; the comparator is used to convert the second pulse signal into a digital pulse according to a set threshold; the multi-hit TDC module is used to trigger the hit TDC multiple times according to the digital pulse to obtain multiple TOFs; the TOF of the last event is used as the final distance information.
[0059] For details, please refer to Figure 2-Figure 5 , Figure 2 The SPAD trigger event waveform diagram provided in the embodiment of the present application is: Figure 3 The peak holder output waveform diagram provided in the embodiment of the present application is as follows: Figure 4 The output waveform diagram of the AC coupling circuit provided in the embodiment of the present application is as follows: Figure 5 This is a comparator output waveform diagram provided in an embodiment of the present application.
[0060] Among them, the SPAD quenching circuit of this embodiment can adopt a variable load quenching circuit (VLQC), and the dead zone duration can be adjusted in the range of 10-200ns. The adjustable duration of the VLQC output digital pulse is set to 5ns, which is equal to the pulse width of the laser. The peak detection method adopted by the peak holder of this embodiment requires time stamping of all peaks detected by the peak detector and overwriting the previously stored TOF value with the latest TOF value. Therefore, it is necessary to adopt a multi-hit TDC with a sufficiently long FSR, good resolution and low dead time in subsequent conversions within the same frame.
[0061] Regarding multi-hit TDC, due to the dead time of SPAD, the resulting pileup phenomenon (photon accumulation) will cause TDC to trigger prematurely (false trigger). For a single-hit TDC, it may not be able to continue to respond to and record subsequent real SPAD trigger events. In order to solve this problem, multi-hit TDC can detect SPAD events multiple times and record the corresponding TOF information. In this solution, since multiple SPAD trigger events need to be measured and recorded, the latter event is obtained based on the previous event and overwrites the TOF of the previous event. The multi-hit TDC uses the TOF of the last event as the final distance information.
[0062] The AC coupling circuit isolates DC and only allows AC to pass. The AC coupling circuit of this embodiment can be considered to be a derivative of the output of the peak holder, thereby generating a pulse at each incremental peak, that is, a pulse is generated only when the latter peak is higher than the previous peak (there is an incremental pulse).
[0063] In the embodiment of the present application, the first pulse signal generated by the SPAD quenching circuit is converted into a voltage waveform signal after passing through the current generator and the transimpedance amplifier, and the shaped signal is obtained by monitoring and tracking the highest peak detected by the peak holder, and the AC coupling circuit tracks the derivative of the shaped signal. The comparator triggers the multi-hit TDC to store TOF information. At the end of the frame (before the next laser shot), the only stored TOF value is the TOF of the last event, that is, the highest signal peak detected in the current frame. This solution does not need to collect histograms, does not need to store more TOF data per frame, and does not need to perform post-processing. It can work in a single-shot state to avoid laser repetition at the same point in the scene, thereby improving the scene acquisition rate of the scanning single-point laser radar.
[0064] Please refer to Figure 6 , Figure 6 This is a flowchart of the working process of the single-photon ranging lidar receiving device provided in an embodiment of the present application.
[0065] In some optional implementations, it also includes: a gating module; the gating module is used to filter out the avalanche current outside the gating period of the first pulse signal, retain the avalanche current within the gating period, and obtain a third pulse signal.
[0066] Please refer to Figure 7 , Figure 7Schematic diagram of non-gated mode and gated mode provided for the embodiment of the present application. The core function of the gated module is that it only allows avalanche currents within a specific gated period to pass through, filtering out all avalanche currents outside the gated period. This mechanism directly reduces the false triggering events caused by the detector's own noise (such as dark counts), thereby significantly reducing the DCR and improving the signal-to-noise ratio of the signal. The gated module can also effectively reduce other types of background noise interference. Because the avalanche currents generated by background light and other non-target signals are mostly not within the preset gated period, these noise signals will be effectively shielded by the gated module, thereby improving the noise resistance of the entire system. By reducing noise interference and DCR, the gated module enables the system to more accurately identify and record valid TOF data. This helps to improve the accuracy and reliability of ranging in complex environments (such as high background noise, multiple reflections, etc.). The gated time of the gated module can be adjusted by an external or internal trigger, and the user can flexibly set the width and frequency of the gate according to the needs of the actual application scenario. This configurability enables the receiving device to adapt to different ranging tasks and environmental conditions, improving the flexibility and applicability of the system.
[0067] In some optional embodiments, it also includes: a random event filter; the random event filter is used to filter out random SPAD trigger events within the gating period of the third pulse signal, retain the real SPAD events related to time, and obtain a fourth pulse signal.
[0068] Please refer to Figure 8 , Figure 8 A schematic diagram of a random SPAD trigger event and a true SPAD trigger event provided in an embodiment of the present application. The random event filter is a configurable SPAD event filter, which is composed of a number of logic AND gates and OR gates interconnected. Since the noise-triggered SPAD event is random, and the true SPAD event is time-related, the random event filter can filter out the random SPAD trigger event during the gated period, while retaining the true SPAD event. Furthermore, some of the SPADs can be selected for random event filtering, thereby increasing accuracy and flexibility, and further increasing precision.
[0069] In some optional embodiments, a current buffer is further included; the current buffer is used to transmit the fourth pulse signal from an input source with extremely small impedance to an output load with high impedance to obtain a fifth pulse signal;
[0070] The current generator is used for converting the fifth pulse signal into a current signal.
[0071] In the embodiment of the present application, the main function of the current buffer is to transmit a signal from an input source with extremely small impedance (such as the fourth pulse signal output by the random event filter) to an output load with high impedance without introducing significant signal attenuation or distortion. This ensures the integrity and quality of the signal and reduces the signal loss caused by impedance mismatch during signal transmission. The current buffer usually has a higher current gain and bandwidth, which can enhance the driving capability of the signal, so that the signal can be transmitted to subsequent processing circuits or devices more stably and reliably. This is especially important for laser radar receiving devices that require high sensitivity and high-speed response.
[0072] In some optional implementations, a plurality of SPAD arrays are included, each SPAD array corresponds to a SPAD quenching circuit, a gating module, a random event filter, and a current buffer:
[0073] The outputs of the multiple current buffers are coupled and then output to the current generator.
[0074] In the embodiment of the present application, multiple SPAD arrays are connected in parallel to aggregate photon detection events, reducing the impact of background noise and saturation. In addition, the outputs of multiple current buffers are coupled and output to the current generator. Due to the effect of the current buffer, the input source with extremely small impedance (effective resistance) is transmitted to the output load with high impedance, preventing the signal source from being affected by any difference in the amount of current absorbed by the output load, so as to aggregate the output currents of the two groups of SPAD arrays, reduce current loss, and output to the current generator.
[0075] Specifically, this embodiment is based on multiple parallel-connected SPAD arrays as receivers of laser echoes, and digital pulses are generated through SPAD quenching circuits, each of which is a variable load quenching circuit (VLQC), and the dead zone duration can be adjusted in the range of 10-100ns. The adjustable duration of the VLQC output digital pulse is set to 5ns, which is equal to the pulse width of the laser. The digital pulse is output to the transimpedance amplifier (TIA) through the current generation circuit to achieve digital-to-analog conversion of the current to the total voltage waveform. The analog signal is then processed by the on-chip analog electronic device and the highest peak detected since the laser emission is monitored by the peak holder. The AC coupling circuit (AC couple) tracks the changes in the signal, and the comparator triggers the multi-hit TDC to store the TOF information. At the end of the frame, before the next laser shot, the only stored TOF value will be the last one, that is, corresponding to the highest signal peak detected in the frame.
[0076] Please refer to Fig. 9 , Fig. 9A flow chart of the steps of a control method for a single-photon ranging laser radar receiving device provided in an embodiment of the present application includes:
[0077] Step S1, using a SPAD array to receive a light signal and generate an avalanche current;
[0078] Step S2, using a SPAD quenching circuit to quench the avalanche current to generate a first pulse signal;
[0079] Step S3, using a current generator to convert the first pulse signal into a current signal;
[0080] Step S4, using a transimpedance amplifier to convert the current signal into a voltage waveform signal;
[0081] Step S5, using a peak holder to detect and hold the peak value of the voltage waveform signal to obtain a shaped signal;
[0082] Step S6, using an AC coupling circuit to remove the DC component of the shaped signal to obtain a second pulse signal;
[0083] Step S7, using a comparator to convert the second pulse signal into a digital pulse according to a set threshold;
[0084] Step S8, using the multi-hit TDC module, triggering the hit TDC multiple times according to the digital pulse to obtain multiple TOFs; taking the TOF of the last event as the final distance information.
[0085] In some optional embodiments, the method further comprises:
[0086] The gate control module is used to filter out the avalanche current outside the gate control period of the first pulse signal, and retain the avalanche current within the gate control period to obtain a third pulse signal.
[0087] In some optional embodiments, the method further comprises:
[0088] The random event filter is used to filter out the random SPAD triggering events within the gated period of the third pulse signal, retain the real SPAD events related to time, and obtain the fourth pulse signal.
[0089] In some optional embodiments, the method further comprises:
[0090] A current buffer is used to transmit the fourth pulse signal from an input source with extremely small impedance to an output load with high impedance, so as to obtain a fifth pulse signal;
[0091] The fifth pulse signal is converted into a current signal by using a current generator.
[0092] In some optional embodiments, the method further comprises:
[0093] The avalanche current generated by each SPAD array is processed in sequence by the corresponding SPAD quenching circuit, gating module, random event filter, and current buffer;
[0094] The outputs of the plurality of current buffers are coupled and then output to the current generator.
[0095] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of the devices or units can be electrical, mechanical or other forms.
[0096] In addition, the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
[0097] Furthermore, the functional modules in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.
[0098] In this document, relational terms such as first and second, etc. are used merely to distinguish one entity or operation from another entity or operation, but do not necessarily require or imply any such actual relationship or order between these entities or operations.
[0099] The above description is only an embodiment of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A single-photon ranging laser radar receiving device, characterized in that: include: SPAD array, SPAD quenching circuit, current generator, transimpedance amplifier, peak holder, AC coupling circuit, comparator, and multi-hit TDC module; The SPAD array is used to receive optical signals and generate avalanche current; The SPAD quenching circuit is used to quench the avalanche current and generate a first pulse signal; The current generator is used to convert the first pulse signal into a current signal; The transimpedance amplifier is used to convert the current signal into a voltage waveform signal; The peak holder is used to detect and hold the peak value of the voltage waveform signal to obtain a shaped signal; The AC coupling circuit is used to remove the DC component of the shaped signal to obtain a second pulse signal; The comparator is used to convert the second pulse signal into a digital pulse according to a set threshold; The multi-hit TDC module is used to trigger the hit TDC multiple times according to the digital pulse to obtain multiple TOFs; and the TOF of the last event is used as the final distance information.
2. The device according to claim 1, characterized in that Also includes: Gating module; The gate control module is used to filter out the avalanche current outside the gate control period and retain the avalanche current within the gate control period for the first pulse signal to obtain a third pulse signal.
3. The device according to claim 2, characterized in that Also includes: Random event filter; the random event filter is used to filter out random SPAD trigger events within the gated period of the third pulse signal, retain the real SPAD events related to time, and obtain the fourth pulse signal.
4. The device according to claim 3, characterized in that Also includes a current buffer; the current buffer is used to transmit the fourth pulse signal from an input source with extremely small impedance to an output load with high impedance to obtain a fifth pulse signal; The current generator is used for converting the fifth pulse signal into a current signal.
5. The device according to claim 4, characterized in that It includes multiple SPAD arrays, each of which corresponds to a SPAD quenching circuit, a gating module, a random event filter, and a current buffer: The outputs of the multiple current buffers are coupled and then output to the current generator.
6. A control method for a single-photon ranging laser radar receiving device, characterized in that: include: Using SPAD array, light signals are received and avalanche current is generated; Using a SPAD quenching circuit to quench the avalanche current and generate a first pulse signal; Using a current generator, converting the first pulse signal into a current signal; Using a transimpedance amplifier, the current signal is converted into a voltage waveform signal; The peak value of the voltage waveform signal is detected and held by using a peak holder to obtain a shaped signal; Using an AC coupling circuit, the DC component of the shaped signal is removed to obtain a second pulse signal; Using a comparator, converting the second pulse signal into a digital pulse according to a set threshold value; Using the multi-hit TDC module, the TDC is triggered multiple times according to the digital pulse to obtain multiple TOFs; the TOF of the last event is used as the final distance information.
7. The method according to claim 6, characterized in that Also includes: The gate control module is used to filter out the avalanche current outside the gate control period of the first pulse signal, and retain the avalanche current within the gate control period to obtain a third pulse signal.
8. The method according to claim 7, characterized in that Also includes: The random event filter is used to filter out the random SPAD triggering events within the gated period of the third pulse signal, retain the real SPAD events related to time, and obtain the fourth pulse signal.
9. The method according to claim 8, characterized in that Also includes: A current buffer is used to transmit the fourth pulse signal from an input source with extremely small impedance to an output load with high impedance, so as to obtain a fifth pulse signal; The fifth pulse signal is converted into a current signal by using a current generator.
10. The method according to claim 9, characterized in that Also includes: The avalanche current generated by each SPAD array is processed in sequence by the corresponding SPAD quenching circuit, gating module, random event filter, and current buffer; The outputs of the plurality of current buffers are coupled and then output to the current generator.