Optical detector and lidar

Abstract

Provided in the present disclosure is an optical detector, comprising: N detectors, the detectors being configured to receive optical signals and output electrical signals, and N being an integer greater than 1; a signal processing circuit, which is connected to the N detectors in a direct-current coupling manner, and is configured to acquire the electrical signals; and a switching group, which is connected to the N detectors and the signal processing circuit, and is configured to connect a target detector to the signal processing circuit, the target detector comprising one or more of the N detectors. The optical detector and a LiDAR provided in the present disclosure can realize gating of target detectors, thereby avoiding crosstalk, and having good detection performance for low-frequency signals.

Description

A photodetector and lidar

[0001] This disclosure claims priority to Chinese Patent Application No. 202411053545.9, filed August 1, 2024, entitled "A Photodetector and LiDAR", and Chinese Patent Application No. 202411396191.8, filed September 30, 2024, entitled "Method for Detecting Pulses, Detector, Related Devices and Storage Medium", the contents of which are incorporated herein by reference in their entirety. Technical Field

[0002] This specification relates to the field of circuit and signal processing technology, and in particular to a photodetector, lidar, a method for detecting pulses, a detector, related equipment and storage medium. Background Technology

[0003] In a lidar system, a detector and its corresponding laser form a detection channel. Multi-line lidar systems typically include multiple detection channels. Due to the non-ideals of the optical path and the circuitry, optical crosstalk and / or electrical crosstalk occur when multiple channels operate simultaneously, leading to inaccurate measurement results at the lidar receiver.

[0004] Signals from the detector can be acquired using AC coupling. However, due to the blocking effect of AC coupling on low-frequency signals, the ground line echo signal is significantly weakened.

[0005] Therefore, it is necessary to design the receiver circuit to select one or more channels to operate within the same time period in order to avoid crosstalk problems and enhance the radar's ability to detect low-frequency signals.

[0006] The information in the background section is merely information known only to the applicant and does not imply that such information had entered the public domain before the date of this application, nor does it imply that it can be considered prior art in this disclosure. Summary of the Invention

[0007] This disclosure provides a photodetector, a lidar, a method for detecting pulses, a detector, related equipment, and a storage medium, which can enable the selection of target detectors, avoid crosstalk, and have good detection performance for low-frequency signals; it can also determine the pulse distribution in the circuit, improving the accuracy of signal processing.

[0008] In a first aspect, this disclosure provides a photodetector, comprising: N detectors, the N detectors including detectors; the detectors being configured to receive optical signals and output electrical signals, the N being an integer greater than 1; a signal processing circuit connected to the N detectors in a DC-coupled manner, configured to acquire the electrical signals; and a switch group connected to the N detectors and the signal processing circuit, configured to connect a target detector to the signal processing circuit, wherein the target detector includes one or more of the N detectors.

[0009] In some implementations, the N detectors include M detector groups, and the M detector groups include detector sets; each detector set includes a first connection terminal and one or more of the detectors, where M is an integer less than N; each of the one or more detectors includes a first terminal and a second terminal; wherein, in the detector group, the first terminal of the one or more detectors is connected to the first connection terminal, and the second terminal of the one or more detectors is connected to the signal processing circuit through the switch group.

[0010] In some implementations, the detector group includes a target detector, and the switch group includes a first switch group configured to connect the target detector in the detector group to the signal processing circuit.

[0011] In some implementations, the switch group further includes: a second switch group comprising P second switches, wherein each of the P second switches is connected to a different detector group, and P is an integer less than or equal to M; the P second switches are configured to output a first target voltage to the first connection terminal of the different detector groups.

[0012] In some implementations, P second switches adjust the first target voltage of the detector group to the operating voltage at different times.

[0013] In some implementations, the P second switches include second switches; the second switches include: a first input terminal for receiving a first voltage; a second input terminal for receiving a second voltage; an output terminal for outputting the first voltage or the second voltage according to a control signal; and a control terminal for receiving the control signal, the control signal switching between a first level and a second level, wherein the first target voltage includes the first voltage and the second voltage.

[0014] In some implementations, when the control signal is at a first level, the output terminal outputs the first voltage.

[0015] In some implementations, when the control signal is at the second level, the output terminal outputs the second voltage.

[0016] In some implementations, the photodetector further includes a level adjustment circuit, the second switch being connected to the level adjustment circuit, wherein the level adjustment circuit is connected to the control terminal and the second input terminal, and is configured to output a control signal based on the second voltage.

[0017] In some implementations, the photodetector further includes a voltage gradient circuit; the voltage gradient circuit is connected between the output terminal of the second switch and the first connection terminal of the detector group, and is configured to receive the voltage at the output terminal and output the first target voltage to the first connection terminal, and the voltage gradient circuit is configured to control the rate at which the first target voltage changes to the operating voltage when the voltage value at the output terminal transitions.

[0018] In some implementations, the photodetector further includes a bias voltage terminal for receiving a bias voltage; different detectors in the detector group are connected to the bias voltage terminal through different first resistors.

[0019] In some implementations, the switch group further includes: a third switch group, comprising a plurality of third switches, the plurality of third switches including third switches; the third switches are connected to the detector and the first resistor corresponding to the detector; wherein, different detectors in the detector group are connected to different third switches.

[0020] In some implementations, the third switch includes a transistor.

[0021] In some implementations, the photodetector further includes a third voltage terminal for receiving a third voltage, wherein the difference between the voltage at the first connection terminal of the detector group and the third voltage is less than the breakdown voltage of the detector; and the second terminals of different detectors in the detector group are connected to the third voltage through different second resistors.

[0022] In some implementations, the photodetector further includes a second voltage supply circuit connected to the first resistor and the signal processing circuit, configured to provide a base voltage to the signal processing circuit.

[0023] In a second aspect, this disclosure also provides a lidar, comprising: a signal transmitter configured to transmit a detection signal; and the photodetector described in the first aspect.

[0024] As can be seen from the above technical solutions, the photodetector and lidar provided in this disclosure have good anti-crosstalk performance and low-frequency signal detection performance. On the one hand, the photodetector can achieve efficient gating of the target detector K by setting one or more sets of switches, thus improving the radar's anti-crosstalk performance. On the other hand, since the photodetector acquires the detector's signal through DC coupling, the radar has high detection accuracy for ground line echoes and ambient light signals.

[0025] Thirdly, embodiments of this disclosure provide a method for detecting pulses, comprising: receiving a signal from a DC-coupled circuit; determining the extreme values ​​of the valleys of the signal; and determining the pulse distribution in the signal based on the extreme values ​​of the valleys.

[0026] Optionally, determining the extreme value of the signal trough includes: determining the signal value corresponding to multiple sampling times within the detection time window; and determining the signal value corresponding to a first time point as the extreme value of the trough based on the signal values ​​corresponding to the multiple sampling times; wherein the first time point is at least one of the multiple sampling times.

[0027] Optionally, determining the signal value corresponding to the first time point as the trough extreme value based on the signal values ​​corresponding to the plurality of sampling times includes: determining the signal value corresponding to the first time point as the trough extreme value based on the comparison result between the signal value corresponding to the sampling time point among the plurality of sampling times and the signal value corresponding to the previous sampling time point of the sampling time.

[0028] Optionally, the comparison result between the signal value corresponding to the sampling time in the plurality of sampling times and the signal value corresponding to the previous sampling time includes a first marker value and a second marker value;

[0029] Wherein, the first marker value indicates that the signal value corresponding to the current sampling time is greater than or equal to the signal value corresponding to the previous sampling time, and the second marker value indicates that the signal value corresponding to the current sampling time is less than the signal value corresponding to the previous sampling time.

[0030] Optionally, the comparison result is represented by bit data.

[0031] Optionally, the signal value corresponding to the first moment is less than the signal value corresponding to each sampling moment within the first preset time period and the second preset time period in the detection time window, wherein the first preset time period is adjacent to the first moment and located before the first moment, the second preset time period is adjacent to the first moment and located after the first moment, and both the first preset time period and the second preset time period include at least one sampling moment.

[0032] Optionally, the comparison result corresponding to each sampling moment within the first preset time period is the second marker value, and the comparison result corresponding to each sampling moment within the second preset time period is the first marker value.

[0033] Optionally, the first preset time period and the second preset time period are set based on the waveform characteristics of the signal.

[0034] Optionally, the signal value corresponding to the first time point is less than the signal value corresponding to the second time point, and the second time point is located before the first time point.

[0035] Optionally, the signal value at the first moment is in an unsaturated state.

[0036] Optionally, the first moment falls within a third preset time period, which is set based on preset parameter values.

[0037] Optionally, the first moment includes a third moment and a fourth moment, wherein the third moment is located before the fourth moment;

[0038] Determining the pulse distribution in the signal based on the valley extreme value includes:

[0039] A first pulse of the signal is determined, the sampling time corresponding to the first pulse is located between the third time moment and the fourth time moment, the peak value of the signal value of the first pulse is greater than a first parameter, and the first parameter is determined based on the signal value corresponding to the third time moment.

[0040] Optionally, the first parameter is determined based on the signal value corresponding to the third time point and a preset parameter value.

[0041] Optionally, the preset parameter value is determined based on the average noise value and root mean square noise value of the signal within the detection time window.

[0042] Fourthly, embodiments of this disclosure also provide a detector configured to receive a signal from a DC-coupled circuit; determine the trough extreme values ​​of the signal; and determine the pulse distribution in the signal based on the trough extreme values.

[0043] Fifthly, embodiments of this disclosure also provide a computer program product, including computer instructions that, when executed by a processor, implement the method for detecting pulses described in any of the above embodiments.

[0044] Sixthly, embodiments of this disclosure also provide a non-volatile computer-readable storage medium having computer instructions stored thereon, which, when executed by a processor, implement the method for detecting pulses described in any of the above embodiments.

[0045] Other functions of the photodetectors and lidars provided in this specification will be partially listed in the following description. The figures and examples described below will be readily apparent to those skilled in the art. The inventive aspects of the photodetectors and lidars provided in this specification can be fully understood through practice or by using the methods, apparatus, and combinations provided in the detailed examples below. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 shows a schematic diagram of a lidar according to some embodiments consistent with this disclosure.

[0048] Figure 2 shows a circuit diagram of a photodetector consistent with some embodiments of the present disclosure.

[0049] Figure 3 shows a circuit diagram of a photodetector consistent with some embodiments of the present disclosure.

[0050] Figure 4 shows a circuit diagram of a photodetector consistent with some embodiments of the present disclosure.

[0051] Figure 5 shows a circuit diagram of a photodetector consistent with some embodiments of the present disclosure.

[0052] Figure 6 shows a circuit diagram of a photodetector consistent with some embodiments of the present disclosure.

[0053] Figure 7 shows a circuit diagram of a photodetector consistent with some embodiments of the present disclosure.

[0054] Figure 8 shows a circuit diagram of a photodetector consistent with some embodiments of the present disclosure.

[0055] Figure 9 shows a circuit diagram of a photodetector consistent with some embodiments of the present disclosure.

[0056] Figure 10 shows an example diagram of a first detection circuit consistent with some embodiments of this disclosure.

[0057] Figure 11 shows an example diagram of a second detection circuit consistent with some embodiments of this disclosure.

[0058] Figure 12 shows an example diagram of the output signal of an AC coupling circuit consistent with some embodiments of this disclosure.

[0059] Figure 13 shows an example diagram of the output signal of a DC-coupled circuit consistent with some embodiments of this disclosure.

[0060] Figure 14 shows an example diagram of a first method consistent with some embodiments of this disclosure.

[0061] Figure 15 shows an example diagram of a second method consistent with some embodiments of this disclosure.

[0062] Figure 16 shows an example diagram of signal sampling consistent with some embodiments of this disclosure.

[0063] Figure 17 shows a schematic diagram of the sampling results of the output signal of a DC-coupled circuit within a detection time window, consistent with some embodiments of this disclosure.

[0064] Figure 18 shows an example diagram of a detector consistent with some embodiments of this disclosure. Detailed Implementation

[0065] The following description provides specific application scenarios and requirements for this specification, intended to enable those skilled in the art to make and use the contents of this specification. Various partial modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of this specification. Therefore, this specification is not limited to the embodiments shown, but rather to the widest scope consistent with the claims.

[0066] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure; the terms “comprising” and “having”, and any variations thereof, in the specification, claims and foregoing description of the drawings of this disclosure are intended to cover non-exclusive inclusion.

[0067] In the description of the embodiments of this disclosure, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of the embodiments of this disclosure, "a plurality of" means two or more, unless otherwise explicitly defined.

[0068] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this disclosure. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0069] Considering the following description, these and other features of this specification, as well as the operation and function of the related components of the structure, and the economy of assembly and manufacture of the parts, can be significantly improved. All of these form part of this specification with reference to the accompanying drawings. However, it should be clearly understood that the drawings are for illustrative and descriptive purposes only and are not intended to limit the scope of this specification. It should also be understood that the drawings are not drawn to scale.

[0070] The flowcharts used in this specification illustrate operations implemented according to some embodiments of this specification. It should be clearly understood that the operations in the flowcharts may not be implemented in a sequential order. Instead, the operations may be implemented in reverse order or simultaneously. Furthermore, one or more additional operations may be added to the flowcharts. One or more operations may be removed from the flowcharts.

[0071] In this specification, "X includes at least one of A, B, or C" means that X includes at least A, or X includes at least B, or X includes at least C. That is, X may include only one of A, B, and C, or any combination of A, B, and C, as well as other possible content / elements. The arbitrary combination of A, B, and C can be A, B, C, AB, AC, BC, or ABC.

[0072] In this specification, unless explicitly stated otherwise, the relationships between structures can be direct or indirect. For example, when describing "A is connected to B," unless it is explicitly stated that A and B are directly connected, it should be understood that A can be directly connected to B or indirectly connected to B. Similarly, when describing "A is on top of B," unless it is explicitly stated that A is directly above B (AB is adjacent and A is above B), it should be understood that A can be directly above B or indirectly above B (AB is separated by other elements, and A is above B). And so on.

[0073] As discussed in the background section, crosstalk occurs when multiple detection channels in a lidar system operate simultaneously, affecting the accuracy of signal readout. Furthermore, the signal reading circuits in related technologies have poor throughput for low-frequency signals, resulting in weak capabilities for ground plane detection and ambient light detection. Therefore, designing the receiver circuit to select multiple detection channels and improving the lidar's response to low-frequency signals are pressing issues for those skilled in the art.

[0074] Figure 1 shows a schematic diagram of a lidar according to some embodiments of the present disclosure. The lidar 001 includes a signal transmitter (e.g., a laser) 020 and a photodetector (e.g., a detector) 010. When the lidar is in operation, the signal transmitter 020 emits a detection signal, such as a laser. The echo signal reflected by the object 002 after the detection signal reaches the object 002 is received by the photodetector 010. The photodetector 010 receives the echo signal and converts it into an electrical signal. After a series of post-processing operations, it obtains the required data, such as one or more parameters of the object 002, including distance, reflectivity, azimuth, height, velocity, attitude, and shape.

[0075] Signal transmitter 020 may include multiple lasers. Signal transmitter 020 may include any one or more types of lasers. For example, the lasers may be vertical cavity surface emitting lasers (VCSELs), photonic crystal surface emitting semiconductor lasers (PCSELs), edge emitting lasers (EELs), etc.

[0076] The photodetector 010 may include multiple detectors. The photodetector 010 may include any one or more types of photodetectors or photodetector arrays. For example, the detector may be an avalanche photodiode (APD) or a single-photon detector. The single-photon detector may include a silicon photomultiplier (SiPM) or a single-photon avalanche diode (SPAD). The detector can respond to optical signals and generate electrical signals under a certain bias voltage. For example, when the bias voltage of the single-photon detector is greater than or equal to its avalanche breakdown voltage, the single-photon detector can respond to optical signals and generate electrical signals.

[0077] A laser and its corresponding detector can form a detection channel. For example, when the laser is working, it emits an outgoing laser beam. When the outgoing laser beam encounters a target object, it is reflected by the target object and becomes a reflected laser beam. The reflected laser beam is detected by the detector, thus forming a detection channel. In some embodiments, a detection channel can consist of one laser beam corresponding to one detector, one laser beam corresponding to multiple detectors, or multiple laser beams corresponding to one detector.

[0078] Within a lidar system, if multiple detection channels operate simultaneously, optical crosstalk and / or electrical crosstalk may occur. Optical crosstalk occurs when a detector receives reflected light from a target object corresponding to another channel, affecting the received signal waveform. If one of the lidar's detection channels has a stronger electrical signal, this stronger signal can crosstalk to the detection circuits of other channels, generating interfering waveforms. To address this crosstalk problem, this disclosure provides a lidar system capable of selecting multiple detectors and acquiring the signal from the selected target detector simultaneously, while ignoring signals from other detectors. This avoids two adjacent detection channels operating simultaneously, thereby reducing the aforementioned crosstalk.

[0079] Furthermore, low-frequency signals such as ground surface echo signals and ambient light signals are of great significance for lidar detection. For example, ground surface echo signals can reflect ground elevation information, helping to determine the altitude of vehicles or aircraft relative to the ground, which is crucial for safe driving. Ambient light signals can be used for point cloud data calculations, including compensation and calibration for the accuracy of point cloud reflectivity and ranging accuracy, playing a vital role in improving radar performance. The lidar disclosed herein acquires electrical signals from the target detector through DC coupling, enhancing its ability to detect low-frequency signals.

[0080] The signals output by DC-coupled circuits are prone to overlap, making it difficult to distinguish between multiple signals, which may reduce the accuracy of signal processing.

[0081] The photodetector 010 will now be described in detail with reference to the accompanying drawings.

[0082] Figure 2 shows a circuit diagram of a photodetector according to some embodiments of the present disclosure. The photodetector 010 includes N detectors 1101, a switch group 130, and a signal processing circuit 150, where N is an integer greater than 1. Figure 2 illustrates an example where N equals 12, meaning the photodetector 010 shown in Figure 2 includes 12 detectors 1101. In some embodiments, N can be any other integer greater than 1.

[0083] When detector 1101 is in operation, it can receive optical signals and output electrical signals. As mentioned above, detector 1101 can be an APD, SPAD, SiPM, etc., and this specification does not limit the type of detector. When the voltage across detector 1101 meets its operating conditions, detector 1101 can respond to optical signals and output electrical signals.

[0084] Switch group 130 is connected to N detectors 1101 and signal processing circuit 150. When the gating switch 130 is working, it can connect the selected target detector K to the signal processing circuit 150. As an example, the target detector K is marked in black in Figure 2. It should be noted that the target detector K can be one or more detectors among the N detectors 1101, and is the detector selected by the switch group 130. Figure 2 is illustrated using the example of the target detector K being one of the N detectors. The gating switch connects the signal of one target detector K to one signal processing circuit 150. In some embodiments, the target detector K can include multiple detectors among the N detectors. The gating switch 130 can connect the signals of multiple target detectors K to multiple corresponding signal processing circuits 150. "Multiple" in this specification means two or more. It should also be noted that Figure 2 shows the gating status of the N detectors 1101 at one moment or during one time period when the switch group 130 is working. At other moments or during other time periods, the target detector K can be other detectors 1101 among the N detectors 1101.

[0085] When the signal processing circuit 150 is operating, it acquires the electrical signal of the target detector K. The signal processing circuit 150 is connected to N detectors 1101 via DC coupling. In some embodiments, the signal processing circuit 150 is directly electrically connected to the N detectors 1101, and both the DC and AC components of the detector output signals can be transmitted to the signal processing circuit 150. The connection between the signal processing circuit 150 and the N detectors 1101 can be direct or indirect. Indirect connection involves the signal processing circuit 150 connecting to the detectors 1101 via a selector switch 130 and / or other electrical components. The selector switch 130 connects the electrical signal of the target detector K to the signal processing circuit 150 while simultaneously disconnecting the signal transmission between the other detectors 1101 and the signal processing circuit 150.

[0086] The photodetector 010 provided in this disclosure can acquire the electrical signal of the target detector K in a DC-coupled manner. On the one hand, compared with the AC-coupled method, the DC-coupled method can reduce the obstruction of low-frequency signals and enhance the detection effect of low-frequency signals, which can be ground line echo signals, ambient light signals, etc. On the other hand, by gating the target detector K (for example, disconnecting the signal transmission between other detectors in the N detectors 1101 and the signal processing circuit 150), the optical crosstalk and / or electrical crosstalk caused by the simultaneous operation of the N detectors 1101 can be reduced to a certain extent.

[0087] Referring again to Figure 2, the N detectors 1101 can comprise M detector groups 111, where M is an integer less than N. Each detector group 111 can include one or more detectors 1101. Figure 2 uses an example where M equals 3, where the 12 detectors 1101 are divided into 3 detector groups, each containing 4 detectors 1101. These 3 detector groups are denoted as 111-A, 111-B, and 111-C for distinction.

[0088] Each detector group 111 may include a first connection terminal C and one or more detectors 1101. The number of detectors 1101 included in each detector group 111 may be the same or different. Detector 1101 may include a first terminal A and a second terminal B. Figure 2 illustrates this with the first terminal A as the cathode of detector 1101 and the second terminal B as the anode of detector 1101 as an example. In practice, detector 1101 may also have the first terminal A as the anode and the second terminal B as the cathode.

[0089] In the same detector group 111, taking detector group 111-A as an example, the first terminal A of the four detectors 1101 in detector group 111-A can be connected to the first connection terminal C of detector group 111A, and the second terminal B of the four detectors 1101 in detector group 111-A can be connected to the signal processing circuit 150 through switch group 130.

[0090] In the same detector group, the second ends of multiple detectors 1101 are not connected together. Between different detector groups 111, the first connection ends C of multiple detectors 1101 can be connected together, for example, the first connection ends C of detector 1101 in detector group 111-A and detector 1101 in detector group 111-B can be connected together (e.g., connected to the same node). Between different detector groups 111, the first connection ends C may also not be connected together, for example, the first connection ends C of detector 1101 in detector group 111-A and detector 1101 in detector group 111-C may not be connected together (e.g., connected to switch group 130 via different ports). The second ends of detectors 1101 may not be connected together between different detector groups 111. Alternatively, the second ends of detectors 1101 may be connected together between different detector groups 111. For example, the second end of each detector 1101 in detector group 111-A and the second end of one detector 1101 in detector group 111-C can be connected together.

[0091] The previous section introduced the grouping and connection method of the N detectors 1101 in the photodetector 010. The following section will introduce the switch group 130 in detail.

[0092] In some embodiments, switch group 130 may include a first switch group. FIG3 shows a circuit diagram of a photodetector provided according to some embodiments of the present disclosure. Switch group 130 may include one or more first switch groups 131. The multiple first switch groups 131 may be of the same type or different types. The first switch group 131 can connect the target detector K in the same detector group 111 to the signal processing circuit 150. The first switch group 131 may be a single device or multiple devices. Taking the first switch group 131 to implement a four-to-one selection from the same detector group 111 as an example. For example, the first switch group 131 may be a multiplexer. For example, the first switch group 131 may also be two single-pole double-throw switches. As another example, the first switch group may also be four single-pole single-throw switches.

[0093] As shown in Figure 3, switch group 130 includes first switch group 131-A and first switch group 131-B. First switch group 131-A consists of two single-pole double-throw switches. First switch group 131-B consists of four single-pole single-throw switches. In some embodiments, first switch group 131-A and first switch group 131-B can both be single-pole double-throw switches or single-pole single-throw switches. During a single selection process, first switch group 131-B can turn on the switch connected to the target detector K, thereby connecting the target detector K to the signal processing circuit 150. For multiple detectors 1101 in the same detector group 111, one detector 1101 is connected to the signal processing circuit 150 at a time.

[0094] For a photodetector 010 comprising multiple first switch groups 131, multiple target detectors K can be selected by controlling the multiple first switch groups 131. The electrical signal output by the selected target detector K can be acquired by the signal processing circuit 150 connected to it. For example, in Figure 3, while the photodetector 010 is conducting target detector K in detector group 111-A, it can also select another target detector in detector group 111-B through the first switch group 131-A. In this way, simultaneous selection of two target detectors K can be achieved. It should be noted that detectors 1101 in the same detector group 111 may not be selected simultaneously.

[0095] In some embodiments, switch group 130 may further include a second switch group. FIG4 shows a circuit diagram of a photodetector provided according to some embodiments of the present disclosure. The second switch group 132 includes P second switches 1321, where P is an integer less than or equal to M. Different second switches 1321 are connected to different detector groups 111. One detector group 111 is connected to one second switch 1321. One second switch 1321 may be connected to one or more detector groups 111. As shown in FIG4, second switch 1321-A is connected to detector group 111-A and detector group 111-B, and second switch 1321-B is connected to detector group 111-C.

[0096] When the second switch 1321 is operational, it outputs a first target voltage to the first connection terminal C of the detector group 111. The second switch 1321 can be directly connected to the first connection terminal C of the detector group 111, or it can be indirectly connected to the first connection terminal C of the detector group 111. The first target voltage at the first connection terminal C can change with the voltage of the second switch 1321. When the first target voltage of the detector group 111 changes to the operating voltage of the detector 1101, the detector 1101 in the detector group 111 can enter a photoresponse state.

[0097] The P second switches 1321 in the second switch group 132 can adjust the first target voltage of their corresponding detector groups 111 to the operating voltage at different times or time periods, thereby enabling the selection of some detector groups in detector groups 111-A, 111-B, and 111-C. As shown in Figure 4, at a certain time or time period, second switch 1321-A can adjust the first target voltage of detector groups 111-A and 111-B to the operating voltage, so that detectors 1101 in these two groups can perform photoresponse. At the same time, the other second switch 1321-B does not adjust the first target voltage of detector group 111-C to the operating voltage, and detectors 1101 in detector group 111-C cannot perform photoresponse or perform very little photoresponse. When detectors 1101 in detector groups 111-A and 111-B are in photoresponse state, they can cooperate with the first switch group 131 to connect the target detector K to the signal processing circuit 150.

[0098] Referring again to Figure 4, each second switch 1321 includes a first input terminal D, a second input terminal E, an output terminal F, and a control terminal G. The first input terminal D can be used to receive a first voltage. The second input terminal E can be used to receive a second voltage. The output terminal F can output either the first voltage or the second voltage according to a control signal. The control terminal G can be used to receive a control signal, which switches between a first level and a second level. When the control signal is at the first level, the output terminal F outputs the first voltage; when the control signal is at the second level, the output terminal F outputs the second voltage. The first target voltage includes both the first voltage and the second voltage. The first voltage can be higher than the second voltage, or it can be lower than the second voltage. This specification uses an example where the first voltage is higher than the second voltage. As shown in Figure 4, the first voltage is used as an example of the operating voltage. When the control signal of the second switch 1321-A is at the first level, the first target voltage of detector group 111-A and detector group 111-B is the first voltage, and detector 1101 in detector group 111-A and detector group 111-B can perform photoresponse; when the control signal of the second switch 1321-B is at the second level, the first target voltage of detector group 111-C is the second voltage, and detector 1101 in detector group 111-C cannot perform photoresponse or performs very little photoresponse. In some embodiments, the second switch can be a CMOS switch, a transistor switch, a multiplexer, etc.

[0099] In some embodiments, the photodetector may further include a level adjustment circuit 160. Figure 5 shows a circuit diagram of a photodetector according to some embodiments of the present disclosure. A second switch 1321 may be connected to the level adjustment circuit 160. The level adjustment circuit 160 may be connected to a control terminal G and a second input terminal E, and can output a control signal based on a second voltage during operation. The control terminal G of the second switch 1321 can switch the output terminal F between a first voltage and a second voltage by switching high and low level signals. The second switch 1321 requires the voltage difference between the level input to its control terminal G and the second voltage to achieve voltage switching to be either high (e.g., 3V) or low (e.g., 0V). Therefore, by setting up the level adjustment circuit 160, the second switch 1321 can still operate normally when the received high and low level signals are not referenced to the second voltage. As shown in Figure 5, in some implementations, the level adjustment circuit 160 may include a capacitor C1, a resistor R1, and a diode D1. When the low-level signal input to port H is less than the second voltage input to the second input terminal E, the voltage difference between the levels input to the control terminal G is made low (e.g., 0V) through capacitor C1, resistor R1, and diode D1, causing the output terminal F of the second switch 1321 to output the second voltage. When the high-level signal input to port H is high, the voltage difference between the levels input to the control terminal G is made high (e.g., 3V) through capacitor C1, resistor R1, and diode D1, causing the output terminal F of the second switch 1321 to output the first voltage. The high-level signal input to port H can be less than, equal to, or greater than the second voltage.

[0100] In some embodiments, the photodetector may further include a voltage gradient circuit 170. The voltage gradient circuit 170 may be connected between the output terminal F of the second switch 1321 and the first connection terminal C of the detector group 111. The voltage gradient circuit 170 may receive the voltage at the output terminal F and output a first target voltage to the first connection terminal C, and control the rate at which the first target voltage changes to the operating voltage when the voltage value at the output terminal F transitions.

[0101] As shown in Figure 5, in some implementations, the voltage gradient circuit 170 may include a resistor R2 and a capacitor C2. When the voltage at the output terminal F experiences a voltage step change, the voltage across capacitor C2 does not change abruptly, therefore the first target voltage output by the voltage gradient circuit 170 does not change abruptly. Taking the common cathode connection of detector group 111 as an example, the voltage difference between the first target voltage at the first connection terminal C and the voltage at the second terminal of detector 1101 is greater than the breakdown voltage of detector 1101, and detector 1101 has the ability to respond to photons. When the voltage at the output terminal F transitions from the second voltage to the first voltage, the voltage at the output terminal F charges capacitor C2 through resistor R2, and the first target voltage output by capacitor C2 rises slowly. As the charging process progresses, the voltage of capacitor C2 gradually increases, the current flowing through resistor R2 gradually decreases, and the charging speed of capacitor C2 through resistor R2 gradually slows down until capacitor C2 reaches the state of being fully charged. Finally, the first target voltage gradually changes to the operating voltage. The voltage gradual change circuit 170 prevents the first target voltage from changing abruptly, reduces high-frequency signals caused by voltage changes, reduces electrical signal noise in the circuit, and reduces the possibility of electrical crosstalk.

[0102] The photodetector 010 provided in this disclosure can select one detector 1101 in the same detector group 111 through the first switch group 131. Furthermore, it can cooperate with the second switch group 132 to select a specific detector group 111. The photodetector 010 provided in this disclosure can select different target detectors at different times, reducing the impact of optical crosstalk and / or electrical crosstalk of the lidar on the detection results.

[0103] Figure 6 shows a circuit diagram of a photodetector according to some embodiments of the present disclosure. The photodetector 010 also includes a bias voltage terminal for receiving a bias voltage VCC. When the first terminal A of detector 1101 reaches its operating voltage and the second terminal B is connected to the bias voltage VCC through a first resistor R11, the voltage difference across detector 1101 exceeds its breakdown voltage, and detector 1101 has the ability to respond to photons. Different detectors 1101 in the same detector group 111 are connected to the bias voltage terminal through different first resistors R11. Detectors 1101 in different detector groups 111 can use the same first resistor R11. As shown in Figure 6, detectors 1101 in detector groups 111-A and 111-B use the same first resistor R11. In some embodiments, detectors 1101 in detector group 111-A are connected to the bias voltage terminal using different first resistors R11. In some embodiments, detectors 1101 in detector group 111-B can also be connected to the bias voltage terminal using different first resistors R11.

[0104] In some embodiments, switch group 130 may further include a third switch group 133. The third switch group 133 may include a plurality of third switches 1331. The third switches 1331 are connected to the second terminal B of detector 1101 and the corresponding first resistor R11. Different detectors 1101 in the same detector group 111 are connected to different third switches 133. When a third switch 1331 is turned on, the second terminal B of the detector 1101 connected to it can be connected to the bias voltage VCC through the first resistor R11. When a third switch 1331 is turned off, the second terminal B of the detector 1101 connected to it cannot be connected to the bias voltage VCC through the first resistor R11. The third switch 1331 may be a transistor. For example, the third switch 1331 may be a PMOS transistor or an NMOS transistor. The third switch 1331 may also be a multiplexer, such as an 8-to-1 multiplexer.

[0105] The photodetector 010 provided in this disclosure can reduce circuit power consumption by using a third switch group 133. Taking Figure 6 as an example, without the third switch group 133, all detectors 1101 in the figure can respond to the optical signal and output electrical signals. The first switch group 131 can select one of the detectors 1101 as the target detector K to be turned on to avoid or reduce crosstalk. However, the remaining detectors 1101 that are not connected to the signal processing circuit 150 will still operate and generate power consumption. In embodiments including the third switch group 133, the third switch 1331 of the detector 1101 that does not need to acquire signals can be turned off. Therefore, the second terminal B of the detector 1101 cannot be connected to the bias voltage VCC through the first resistor R11 and cannot enter the operating state, thereby reducing power consumption.

[0106] Because detector 1101 may have leakage current, when the circuit includes a third switch group 133, when the third switch group 133 is open, the voltage at the end of the third switch 1331 connected to detector 1101 will slowly rise due to the leakage current of detector 1101. This leakage problem may cause the third switch 1331 to malfunction. Taking a transistor as an example, when the voltage at one port of the transistor continuously increases, the voltage difference between it and other ports will also change, affecting the control of its switching state.

[0107] In some embodiments, the photodetector 010 may further include a third voltage terminal. Figure 7 shows a circuit diagram of a photodetector provided according to some embodiments of the present disclosure. The third voltage terminal is used to receive a third voltage V3. The difference between the voltage at the first connection terminal C of the detector group 111 and the third voltage V3 is less than the breakdown voltage of the detector 1101. That is, after connecting the third voltage V3, the difference between the voltage at the first connection terminal C and the third voltage V3 will not cause the detector 1101 to enter a normal operating state. The second terminals B of different detectors 1101 in the same detector group 111 are connected to the third voltage V3 through different second resistors R22. By setting the third voltage terminal V3 and the second resistor R22, the voltage at the second terminal B of the detector 1101 can remain stable when the third switch 1331 is open.

[0108] The signal processing circuit 150 may include an amplifier and an analog-to-digital converter (ADC). When the target detector K is active but does not respond to the light output signal, the voltage acquired by the ADC is the voltage at point S in Figure 7. If there is a requirement for the magnitude of the voltage acquired by the ADC when the target detector K has no signal output (e.g., the base voltage), the voltage at point S needs to be provided by the circuit. For this purpose, in some embodiments, the voltage at point S can be made to reach the base voltage by directly adjusting the value of VCC. In some embodiments, the photodetector may also include a second voltage supply circuit. Figure 8 shows a circuit diagram of a photodetector according to some embodiments of the present disclosure. The second voltage supply circuit 180 is connected to the first resistor R11 and the signal processing circuit 150. The second voltage supply circuit 180 can provide the base voltage V0 to the signal processing circuit 150. For example, referring to Figure 8, when the target detector K is in operation, it is connected to the signal processing circuit 150 via the first switch group 131-B. When the target detector K does not respond to the optical signal and output an electrical signal, the signal processing circuit 150 acquires the base voltage V0 provided by the second voltage supply circuit 180. In some embodiments, the second voltage supply circuit 180 can also provide a fourth voltage V4 to the signal processing circuit 150. The fourth voltage V4 can be used to provide operating voltage or reference voltage for electronic components in the second voltage supply circuit 180. For example, when the signal processing circuit 150 includes an ADC, the fourth voltage V4 can be used to provide a power supply voltage or a reference voltage for the ADC. This specification does not limit the specific implementation of the second voltage supply circuit.

[0109] Figure 9 shows a circuit diagram of a photodetector according to some embodiments of the present disclosure. As shown in Figure 9, the photodetector 010 includes a first switch group 131, a second switch group 132, and a third switch group 133. The first switch group 131 controls the switching on and off of the detector and the signal processing circuit 150. To improve the selection efficiency, the second switch group 132 can select the detector group 111-A, which includes the target detector K. The selection method can be to adjust the first target voltage of the first connection terminal C of the detector group 111-A to the operating voltage of the detector 1101. The third switch group 133 can connect or disconnect the second terminal of the detector 1101 from the bias voltage. When the detector group 111-A is selected by the second switch 1321, the first terminals A of the detectors in the detector group are all at the operating voltage. The third switch group 133 can disconnect the remaining detectors 1101 except the target detector K from the bias voltage to reduce circuit power consumption.

[0110] In summary, the photodetector and lidar provided in this disclosure have good anti-crosstalk performance and low-frequency signal detection performance. On one hand, the photodetector 010 can achieve efficient gating of the target detector K by setting one or more sets of switches, thus improving the radar's anti-crosstalk performance. On the other hand, since the photodetector 010 acquires the signal from the detector 1101 through DC coupling, the radar has high detection accuracy for ground line echoes and ambient light signals.

[0111] Referring to Figure 10, which shows an example diagram of a first detection circuit consistent with some embodiments of this disclosure. Referring to Figure 10, the first detection circuit includes multiple detectors 201, a gating circuit 202, a signal processing circuit 203, and a coupling circuit 204. Detectors 201 can receive optical signals and output electrical signals during operation. Detectors 201 can be detectors of the type APD, SPAD, or SiPM, etc. When the voltage across detector 201 meets its operating conditions, detector 201 can respond to optical signals and output electrical signals. The gating circuit 202 can be coupled between the multiple detectors 201 and the signal processing circuit 203. The gating circuit 202 can control the conduction or deactivation between the signal processing circuit 203 and each detector 201. The gating circuit 202 may include a multiplexer or a data selector, etc.

[0112] In some embodiments, the number of detectors is the same as the number of signal processing circuits. For example, each detector has a corresponding signal processing circuit that processes its output electrical signal. In this case, the first detection circuit may not include a gating circuit.

[0113] In some embodiments, detector 201 can be coupled to signal processing circuit 203 via coupling circuit 204. For example, coupling circuit 204 can be coupled between multiple detectors 201 and signal processing circuit 203. As another example, coupling circuit 204 can be coupled between multiple detectors 201 and gating circuit 202. Yet another example, coupling circuit 204 can be coupled between gating circuit 202 and signal processing circuit 203.

[0114] The signal processing circuit 203 may include devices such as amplifiers, integrators, or analog-to-digital converters. For example, by integrating the DC signal output by the detector over time using an integrator, ambient light information can be determined, and further, reflectivity information can be determined. As another example, by amplifying the electrical signal output by the detector, the signal strength can be increased.

[0115] Figure 11 shows an example diagram of a second detection circuit consistent with some embodiments of this disclosure. Referring to Figure 11, the second detection circuit includes a plurality of detectors 301, a gating circuit 302, a signal processing circuit 303, and a coupling circuit 304. The detectors 301, gating circuit 302, and signal processing circuit 303 can be referred to the relevant descriptions of detectors 201, gating circuit 202, and signal processing circuit 203 in the first detection circuit.

[0116] The signal processing circuit 303 can be connected to multiple detectors 301 via AC coupling. For example, referring to FIG11, multiple detectors 301 are connected to a gating circuit 302 via a coupling circuit 304 (e.g., a capacitor), and then connected to the signal processing circuit 303 via the gating circuit 302.

[0117] DC-coupled circuits do not attenuate echo signals with small amplitudes and large pulse widths, such as ground line echoes. In this case, the lidar's ability to detect ground lines can be enhanced. For example, compared to AC-coupled circuits, which can detect ground lines up to 50 meters away, DC-coupled circuits can detect ground lines up to 60 meters away.

[0118] Figure 12 shows an example output signal diagram of an AC coupling circuit consistent with some embodiments of this disclosure. Figure 13 shows an example output signal diagram of a DC coupling circuit consistent with some embodiments of this disclosure. Referring to Figure 12, the AC coupling circuit (e.g., the AC coupling circuit shown in Figure 11) has the characteristic of passing high frequencies and blocking low frequencies, resulting in poor transmission of echo signals with small amplitude and large pulse width. The AC coupling circuit may attenuate the echo signals with small amplitude and large pulse width significantly. The AC coupling circuit may also transform the already transmitted echo signals with small amplitude and large pulse width into echo signals with large amplitude and small pulse width, for example, transforming a "short and wide" signal into a "slender and tall" signal. This is beneficial for distinguishing multiple pulse signals. Referring to Figure 13, the DC coupling circuit does not attenuate the echo signals with small amplitude and large pulse width. However, these echo signals with small amplitude and large pulse width tend to overlap. It is difficult to distinguish between multiple pulse signals. This may reduce the accuracy of signal processing, thereby affecting the detection of objects by the lidar.

[0119] Therefore, determining the pulse distribution in the signal output by the DC-coupled circuit and improving the accuracy of signal processing is of great significance for identifying relevant information in the signal.

[0120] Some embodiments of this disclosure provide methods for detecting pulses. These methods can determine the extreme troughs of a received signal from a DC-coupled circuit, and thus determine the pulse distribution within the signal.

[0121] Figure 14 illustrates an example diagram of a first method consistent with some embodiments of this disclosure. The first method can be used to detect pulses. The first method can be performed by a first device, for example, the first device including at least one of an integrated circuit with processing capabilities, or a processor. For example, the processor can be a central processing unit (CPU), a microprocessor, or a field-programmable gate array (FPGA), etc. Referring to Figure 14, the first method includes 601, 602, and 603.

[0122] In 601, signals are received from the DC-coupled circuit.

[0123] At 602, determine the extreme values ​​of the signal's troughs.

[0124] In 603, the pulse distribution in the signal is determined based on the trough extremes.

[0125] It is understood that the steps or portions included in the methods of this disclosure are not fixed. In some embodiments, fewer steps or portions may be included. For example, determining the trough extrema of the signal and determining the pulse distribution in the signal based on the trough extrema may be performed in one step. In some embodiments, more steps or portions may be included. For example, a preprocessing step of the received signal from the DC-coupled circuit may also be included.

[0126] In some embodiments, the lidar receives echo signals through a detector, and the received echo signals can be sent to a signal processing circuit for processing via a DC coupling circuit.

[0127] In some embodiments, the first device may receive a signal directly from a DC-coupled circuit. For example, the first device receives a signal directly output from a DC-coupled circuit. The first device includes at least one of a signal processing circuit, an integrated circuit with processing capabilities, or a processor.

[0128] In some embodiments, the first device can receive signals indirectly from a DC-coupled circuit. For example, the first device receives signals indirectly output by the DC-coupled circuit, such as signals output by the DC-coupled circuit being processed by a signal processing circuit before being sent to the first device for processing. For example, referring to FIG10, the first device can receive signals sent by the signal processing circuit 203.

[0129] A trough extreme value can be a local minimum value in a signal waveform. As a turning point in the signal, a trough extreme value typically lies between two adjacent pulses. A first device can determine the trough extreme values ​​of the received signal and, based on these values, determine the pulse distribution of the signal. This can improve the accuracy of signal processing.

[0130] Figure 15 illustrates an example diagram of a second method consistent with some embodiments of this disclosure. The second method can be used to determine the extreme values ​​of a signal's troughs. The second method can also be performed by the first device. Referring to Figure 15, the second method includes 701 and 702.

[0131] In step 701, the signal values ​​corresponding to multiple sampling times within the detection time window are determined.

[0132] In some embodiments, after receiving a signal from a DC-coupled circuit, the first device can sample the signal. Alternatively, other devices with sampling capabilities can sample the signal, and the first device communicates with such devices. Alternatively, the first device can read the sampling result obtained by the device with sampling capabilities to determine the signal value corresponding to the sampling time. The following description uses the example of the first device sampling the signal.

[0133] In some embodiments, the signal can be sampled within one or more time windows, and the sampling time and the signal value at that sampling time can be stored. The length of the time window can be fixed or variable. The first device can determine the signal value corresponding to multiple sampling times within the detection time window by reading the stored signal values ​​corresponding to multiple sampling times. The detection time window can include one time window or multiple time windows.

[0134] In some embodiments, the first device can sample the signal of the DC-coupled circuit within a detection time window to determine the signal values ​​corresponding to multiple sampling times. The sampling times can be preset. Adjacent sampling times can be spaced out by the same duration, or adjacent sampling times can be spaced out by different durations.

[0135] Figure 16 shows an example diagram of signal sampling consistent with some embodiments of this disclosure. The horizontal axis t represents the signal time, and the vertical axis RSS represents the strength value of the received signal. The signal strength can be represented by power or voltage, etc., and the unit of the vertical axis RSS can be watts (W) or volts (V). Referring to Figure 16, the first device can sample the signal from the DC-coupled circuit to obtain multiple sampling points, for example, A0 to A10 shown in Figure 16. 13 Where A0 is denoted as (t0, v0), A1 as (t1, v1), ..., A 13 The coordinates of (t) 13 ,v 13 ).

[0136] In step 702, based on the comparison between the signal values ​​corresponding to multiple sampling times and the signal value corresponding to the previous sampling time, the signal value corresponding to the first sampling time is determined to be a trough extreme value. Here, the first sampling time is at least one of the multiple sampling times.

[0137] The first device can compare the signal values ​​corresponding to multiple sampling times with the signal value corresponding to the previous sampling time to determine the magnitude comparison result.

[0138] In some embodiments, for all sampling moments within the detection time window, the signal values ​​corresponding to a portion of the sampling moments can be selected and compared with the signal values ​​corresponding to the previous sampling moment to determine the magnitude comparison result.

[0139] For example, please continue to refer to Figure 16, for sampling points A0 to A1 shown in Figure 16 13You can select any number of consecutive sampling points, such as A1 to A8, and determine the magnitude comparison results of the intensity values ​​of these sampling times with the intensity values ​​of the previous sampling times by comparing the intensity values ​​of A1 and A0, A2 and A1, A3 and A2, A4 and A3, A5 and A4, A6 and A5, A7 and A6, and A8 and A7 respectively.

[0140] In some embodiments, the signal value corresponding to a sampling moment within the detection time window is compared with the signal value corresponding to the previous sampling moment, and the comparison result is determined. For example, the above operation is performed for each sampling moment within the detection time window. Alternatively, the above operation is performed for multiple sampling moments within the detection time window.

[0141] For example, please continue to refer to Figure 16, for sampling points A0 to A1 shown in Figure 16 13 By comparing the intensity values ​​of A1 and A0, A2 and A1, A3 and A2, A4 and A3, A5 and A4, A6 and A5, A7 and A6, A8 and A7, A9 and A8, A10 and A9, A11 and A10, A12 and A11, and A13 and A12 respectively, the comparison results of the intensity values ​​of these sampling times with their previous sampling times are determined. For sampling points without a previous sampling time, such as sampling point A0, the comparison result of the intensity values ​​of sampling point A0 with its previous sampling time can be set to be consistent with the comparison result of the intensity values ​​of A1 and A0.

[0142] In some embodiments, the trough extreme value can be determined based on the above magnitude comparison results. The trough extreme value is smaller than the preceding signal value and also smaller than the following signal value. The sampling time corresponding to the determined trough extreme value is called the first sampling time. The first sampling time can be one sampling time or multiple sampling times.

[0143] For example, referring to Figure 16, in the comparison of the intensity values ​​of A1 and A0, A2 and A1, A3 and A2, A4 and A3, A5 and A4, A6 and A5, A7 and A6, A8 and A7, A9 and A8, A10 and A9, A11 and A10, A12 and A11, and A13 and A12, the intensity value of A6 is less than that of A5, and the intensity value of A6 is less than that of A7. Therefore, A6 is a trough extreme value, and the sampling time t6 corresponding to A6 is the first time point. Similarly, the intensity value of A12 is less than that of A11, and the intensity value of A12 is less than that of A13. Therefore, A12 is a trough extreme value, and the sampling time t6 corresponding to A12 is... 12 It was the first moment.

[0144] In some embodiments, when the signal sampling rate is high and the processing clock frequency is low, multiple size comparison results can be processed in parallel, thereby improving the real-time performance of pulse detection.

[0145] For example, referring to Figure 16, within a single processing clock cycle, the magnitude comparison results of the intensity values ​​of eight consecutive sampling points with their previous sampling time can be determined simultaneously. For example, for sampling points A0 to A10 shown in Figure 16... 13 Within 7 processing clock cycles, 7 sets of comparison results can be determined respectively: the comparison results of the intensity values ​​of each time point in A0 to A7 with the intensity values ​​of the previous sampling time point; the comparison results of the intensity values ​​of each time point in A1 to A8 with the intensity values ​​of the previous sampling time point; the comparison results of the intensity values ​​of each time point in A2 to A9 with the intensity values ​​of the previous sampling time point; the comparison results of the intensity values ​​of each time point in A3 to A10 with the intensity values ​​of the previous sampling time point; the comparison results of the intensity values ​​of each time point in A4 to A11 with the intensity values ​​of the previous sampling time point; the comparison results of the intensity values ​​of each time point in A5 to A12 with the intensity values ​​of the previous sampling time point; and the comparison results of the intensity values ​​of each time point in A6 to A13 with the intensity values ​​of the previous sampling time point.

[0146] In some embodiments, the magnitude comparison result can be determined by subtracting the signal value corresponding to the current sampling time from the signal value corresponding to the previous sampling time.

[0147] In the above embodiments, the current sampling time refers to the sampling time at which the current sampling time is being compared with the previous sampling time, rather than the sampling time itself.

[0148] For example, referring to Figure 16, when comparing the intensity values ​​of A1 and A0, the sampling time corresponding to A1 is the current sampling time. When comparing the intensity values ​​of A2 and A1, the sampling time corresponding to A2 is the current sampling time. When comparing the intensity values ​​of A3 and A2, the sampling time corresponding to A3 is the current sampling time, and so on.

[0149] In some embodiments, the magnitude comparison result can be determined by dividing the signal value corresponding to the current sampling time by the signal value corresponding to the previous sampling time.

[0150] It is understood that the embodiments of this disclosure do not impose specific limitations on how to compare the magnitudes of signal values, as long as the determined comparison result can characterize the magnitude difference between signal values.

[0151] Compared to directly determining the extreme values ​​of a signal trough based on signal values ​​at multiple sampling times, the method described in the above embodiments simplifies the processing logic by determining the extreme value of the signal at the first sampling time based on a comparison between the signal values ​​at multiple sampling times and the signal value at the previous sampling time. This not only improves the real-time performance of pulse detection but also reduces processing resource consumption.

[0152] In some embodiments, a first marker value can be used to indicate that the signal value corresponding to the current sampling time is greater than or equal to the signal value corresponding to the previous sampling time, and a second marker value can be used to indicate that the signal value corresponding to the current sampling time is less than the signal value corresponding to the previous sampling time. The comparison result of the signal values ​​corresponding to multiple sampling times with the signal values ​​corresponding to the previous sampling time includes the first marker value and the second marker value.

[0153] Since the characteristic of a trough extreme value is that it is less than the previous signal value and less than the next signal value, when determining the signal value corresponding to the first moment as a trough extreme value based on the comparison results of the signal values ​​corresponding to multiple sampling moments with the signal value corresponding to the previous sampling moment, the comparison results of the signal values ​​corresponding to multiple sampling moments with the signal value corresponding to the previous sampling moment should include a first marker value indicating that the signal value corresponding to the current sampling moment is greater than or equal to the signal value corresponding to the previous sampling moment, and a second marker value indicating that the signal value corresponding to the current sampling moment is less than the signal value corresponding to the previous sampling moment.

[0154] By using the above embodiments, the first marker value indicates that the signal value corresponding to the current sampling time is greater than or equal to the signal value corresponding to the previous sampling time, and the second marker value indicates that the signal value corresponding to the current sampling time is less than the signal value corresponding to the previous sampling time. This can further simplify the processing logic for determining the extreme value of the trough, thereby further improving the real-time performance of pulse detection.

[0155] In some embodiments, the first and second flag values ​​can be represented by a single bit of data. For example, when comparing the signal value at the current sampling time with the signal value at the previous sampling time, if the result of the subtraction is greater than or equal to 0, that is, the signal value at the current sampling time is greater than or equal to the signal value at the previous sampling time, the comparison result can be represented by "1"; if the result of the subtraction is less than zero, that is, the signal value at the current sampling time is less than the signal value at the previous sampling time, the comparison result can be represented by "0". When the signal value at the first moment is determined to be a trough extreme value based on the comparison results of the signal values ​​at multiple sampling times with the signal values ​​at the previous sampling time, the comparison result includes at least one set of "01".

[0156] For example, when comparing the signal value at the current sampling time by dividing it by the signal value at the previous sampling time, if the result of the division is greater than or equal to 1 (meaning the signal value at the current sampling time is greater than or equal to the signal value at the previous sampling time), the comparison result can be represented by "0"; if the result of the division is less than 1 (meaning the signal value at the current sampling time is less than the signal value at the previous sampling time), the comparison result can be represented by "1". When determining the signal value at the first sampling time as a trough extreme based on the comparison results of signal values ​​at multiple sampling times with the signal value at the previous sampling time, the comparison result must include at least one set of "10".

[0157] For example, referring to Figure 16, within a single processing clock cycle, the magnitude comparison results of multiple consecutive sampling points with their previous sampling time can be determined simultaneously. For instance, the magnitude comparison results of each time point from A2 to A9 with their previous sampling time can be determined simultaneously. Dividing the signal values ​​of A3 and A2, if the result is less than 1, is represented by "1". Dividing the signal values ​​of A4 and A3, if the result is less than 1, is represented by "1". Dividing the signal values ​​of A5 and A4, if the result is less than 1, is represented by "1". Dividing the signal values ​​of A6 and A5, if the result is less than 1, is represented by "1". Dividing the signal values ​​of A7 and A6, if the result is greater than 1, is represented by "0". Dividing the signal values ​​of A8 and A7, if the result is greater than 1, is represented by "0". Dividing the signal values ​​of A9 and A8, the result of which is greater than 1 is represented by "0". The comparison result of A2 with the signal from the previous sampling time is the same as the comparison result of A3 with A2, and is represented by "1". A comparison result of "11111000" can be obtained. Based on the above comparison result, the sampling time corresponding to A6 can be determined as the first time, and the signal value corresponding to A6 is the extreme value of the trough.

[0158] For example, please continue referring to Figure 16, and simultaneously determine the magnitude comparison result of the intensity value of each time step A3 to A10 with its previous sampling time step. Divide the signal value of A4 by the signal value of A3; if the result is less than 1, use "1" to represent the magnitude comparison result. Divide the signal value of A5 by the signal value of A4; if the result is less than 1, use "1" to represent the magnitude comparison result. Divide the signal value of A6 by the signal value of A5; if the result is less than 1, use "1" to represent the magnitude comparison result. Divide the signal value of A7 by the signal value of A6; if the result is greater than 1, use "0" to represent the magnitude comparison result. Divide the signal value of A8 by the signal value of A7; if the result is greater than 1, use "0" to represent the magnitude comparison result. Dividing the signal values ​​of A9 and A8 by a factor of 1, the result is represented by "0". Similarly, dividing the signal values ​​of A10 and A9 by a factor of 1, also results in a value greater than 1, represented by "0". The comparison result of A3 with the signal from the previous sampling time is the same as the comparison result of A4 with A3, represented by "1". This yields a comparison result of "11110000". Based on this comparison result, the sampling time corresponding to A6 can be determined as the first time step, and the signal value corresponding to A6 is a trough extreme value.

[0159] In some embodiments, the signal value corresponding to the first moment may be less than the signal value corresponding to a sampling moment within a first preset time period and a second preset time period within the detection time window. The first preset time period is adjacent to and precedes the first moment, and the second preset time period is adjacent to and follows the first moment. Both the first and second preset time periods include at least one sampling moment. For example, the signal value corresponding to the first moment may be less than the signal value corresponding to each sampling moment within the first and second preset time periods within the detection time window. As another example, the signal value corresponding to the first moment may be less than the signal values ​​corresponding to multiple sampling moments within the first and second preset time periods within the detection time window.

[0160] For example, both the first and second preset time periods can include a sampling time. Since the characteristic of a trough extreme value is that it is less than both the preceding and following signal values, the signal value corresponding to the first time point can be determined as a trough extreme value when it is less than the signal value corresponding to a sampling time point preceding and adjacent to the first time point, and less than the signal value corresponding to a sampling time point following and adjacent to the first time point. The method in this embodiment has low computational complexity, which is beneficial for improving the real-time performance of pulse detection.

[0161] For example, both the first and second preset time periods can include multiple sampling moments. When the signal value corresponding to the first moment is less than the signal values ​​corresponding to multiple sampling moments in the first preset time period that are before and adjacent to the first moment, and less than the signal values ​​corresponding to multiple sampling moments in the second preset time period that are after and adjacent to the first moment, the signal value corresponding to the first moment can be determined as a trough extreme value. Furthermore, since the signal value corresponding to the first moment is less than the signal value corresponding to each sampling moment within the first and second preset time periods in the detection time window, the effective falling edge before the trough extreme value and the effective rising edge after the trough extreme value can be determined, thereby reducing noise interference and improving the accuracy of pulse detection.

[0162] It is understood that the embodiments of this disclosure do not impose specific limitations on the first preset time period and the second preset time period. The number of sampling moments included in the first preset time period and the second preset time period may be the same or different. In some embodiments, the first preset time period may include one sampling moment, and the second time period may include multiple sampling moments. In some embodiments, the first preset time period may include multiple sampling moments, for example, two sampling moments. The second time period may include multiple sampling moments, for example, four sampling moments.

[0163] In some embodiments, the comparison result corresponding to a sampling moment within a first preset time period is a second marker value, and the comparison result corresponding to a sampling moment within a second preset time period is a first marker value. For example, the comparison result corresponding to each sampling moment within the first preset time period is a second marker value, and the comparison result corresponding to each sampling moment within the second preset time period is a first marker value. As another example, the comparison results corresponding to multiple sampling moments within the first preset time period are second marker values, and the comparison results corresponding to multiple sampling moments within the second preset time period are first marker values.

[0164] For example, based on the characteristics of the trough extreme value, if a valid falling edge precedes the trough extreme value, then the trough extreme value is less than the signal value corresponding to each sampling moment within the first preset time period. Accordingly, the comparison result corresponding to each sampling moment within the first preset time period can be represented by a second marker value, as mentioned above, where the second marker value indicates that the signal value corresponding to the current sampling moment is less than the second marker value of the signal value corresponding to the previous sampling moment. If a valid rising edge follows the trough extreme value, then the trough extreme value is less than the signal value corresponding to each sampling moment within the second preset time period. Accordingly, the comparison result corresponding to each sampling moment within the second preset time period can be represented by a first marker value, as mentioned above, where the first marker value indicates that the signal value corresponding to the current sampling moment is greater than or equal to the signal value corresponding to the previous sampling moment.

[0165] Optionally, for sampling moments located at the edge of the first preset time period, i.e. sampling moments without a previous sampling moment, the comparison result can be set to be consistent with the comparison result of its subsequent sampling moment.

[0166] In some embodiments, the first preset time period and the second preset time period are set based on the waveform characteristics of the signal. For example, when the signal amplitude is large, both the first preset time period and the second preset time period may include multiple sampling moments. Alternatively, when the signal amplitude is small, both the first preset time period and the second preset time period may include only one sampling moment.

[0167] In some embodiments, the first device can determine the signal value corresponding to the first time moment as a trough extreme value when it determines that the signal value at the first time moment is less than the signal value at the second time moment, wherein the second time moment is before the first time moment. This improves the accuracy of the determined trough extreme value. For example, when processing signals from a DC-coupled circuit in a lidar system, during actual lidar detection, the incident angle of the detection signal may not be perpendicular to the object being measured. This situation may cause the echo signal reflected from the object to have a plateau with a slow rising edge, leading to incorrect determination of the trough extreme value. Therefore, by determining that the signal value corresponding to the first time moment is less than the signal value corresponding to the second time moment, which is before the first time moment, a valid falling edge can be determined before the signal value corresponding to the first time moment, thereby improving the accuracy of the determined trough extreme value.

[0168] In some embodiments, when it is determined that the signal value corresponding to the first time moment is in an unsaturated state, the first device can determine that the signal value corresponding to the first time moment is a trough extreme value. Since the trough extreme value in a saturated state does not have suitable leading-edge features, it may not accurately represent the true change of the signal. Therefore, when the signal value corresponding to the first time moment is in an unsaturated state, determining that the signal value corresponding to the first time moment is a trough extreme value can further improve the accuracy of the determined trough extreme value, thereby further improving the accuracy of signal processing.

[0169] In some embodiments, if the first moment falls within a third preset time period, the signal value corresponding to the first moment can be determined as a trough extreme value, wherein the third preset time period is set based on preset parameter values. This approach can further improve the accuracy of the determined trough extreme value.

[0170] Noise may exist in DC-coupled circuits. In some embodiments, a preset parameter value can be set, and portions smaller than the preset parameter value are considered noise and not processed by pulse detection. Portions larger than the preset parameter value are considered valid signals, and only the pulse distribution within the valid signals is determined. This reduces pulse detection processing time and improves processing accuracy. In some embodiments, signal values ​​near the preset parameter value may also be noise, and trough extreme values ​​can be determined within a preset time period. For example, if the first moment falls within a third preset time period, the signal value corresponding to the first moment is determined to be a trough extreme value. The third preset time period can be any time period within the detection time window, excluding the time period corresponding to signal values ​​that might be considered noise. This reduces the probability of identifying potentially noisy signal values ​​near the preset parameter value as trough extreme values, further improving the accuracy of the determined trough extreme values, and thus further improving the accuracy of signal processing.

[0171] Figure 17 shows a schematic diagram of the sampling results of the output signal of a DC-coupled circuit within a detection time window, consistent with some embodiments of this disclosure. Referring to Figure 17, r1 is a preset parameter value. Signal values ​​greater than r1 are considered valid signals. Since the signal values ​​corresponding to sampling times t0 and t3 are equal to the preset parameter value, the signal values ​​corresponding to sampling times in the sampling periods [t0, t0'] near sampling time t0 and [t3', t3] near sampling time t3 are not significantly different from the preset parameter value, and may be noise. Therefore, the extreme values ​​of the troughs detected within the above sampling periods are unreliable and can be discarded. In this embodiment, the sampling periods [t0, t0'] and [t3', t3] are considered to be the time periods corresponding to noise. The third preset time period can be any time period within the detection time window [t0', t3']. For example, the third preset time period can be [t0', t3']. Another example is [t0', t2]. Yet another example is [t1, t3'].

[0172] It is understood that the embodiments disclosed herein do not impose specific limitations on the third preset time period, and the third preset time period in the above embodiments is merely illustrative. Those skilled in the art can set the time period according to the actual application scenario of the DC-coupled circuit and the noise rate of the signal from the DC-coupled circuit.

[0173] In some embodiments, the first time point may include multiple sampling times, for example, it may include a third time point and a fourth time point, with the third time point preceding the fourth time point. Accordingly, at 603, a first pulse of the signal can be determined, the sampling time corresponding to the first pulse being between the third and fourth time points, and the peak value of the signal value of the first pulse being greater than a first parameter, the first parameter being determined based on the signal value corresponding to the third time point.

[0174] Optionally, after determining the signal values ​​corresponding to the third and fourth moments as trough extremes, the determined trough extremes can be used as the last point of the previous pulse and simultaneously as the first point of the next pulse to segment the signal and determine the first pulse. By determining that the peak value of the first pulse is greater than the first parameter, the probability of misidentifying a noise pulse as the first pulse can be reduced.

[0175] For example, continuing to refer to Figure 17, in the signal sampling results shown in Figure 17, the first time includes the third time t1 and the fourth time t2. The third time t1 is located before the fourth time t2. Based on the signal values ​​corresponding to the third time t1 and the fourth time t2, the signal sampling results are segmented to identify pulse M0, the first pulse M1, and pulse M2. The sampling time corresponding to the first pulse M1 is located between the third time t1 and the fourth time t2. The signal value corresponding to the third time t1 is used as the baseline value of the first pulse M1, and thus the first parameter can be determined.

[0176] In some embodiments, the first parameter is determined based on the signal value corresponding to the third time moment and a preset parameter value.

[0177] For example, the first parameter can be the sum of the signal value at the third moment and the preset parameter value. As before, the portion smaller than the preset parameter value can be regarded as noise, the signal value at the third moment can be used as the baseline value of the first pulse, and the preset parameter value can be added to the baseline value as the first parameter. By confirming that the peak value of the signal value of the first pulse is greater than the first parameter, the probability of misidentifying the noise waveform as the first pulse can be reduced.

[0178] In some embodiments, the preset parameter values ​​are determined based on the average noise value and the root mean square noise value of the signal within the detection time window.

[0179] In some embodiments, the predetermined preset parameter value can be adjusted according to the noise rate of the signal.

[0180] For example, if the preset parameter value is too low, the noise will be greater than the preset parameter value, becoming noise in the effective pulse and resulting in a high noise rate in the signal. In this case, the preset parameter value can be appropriately increased.

[0181] This disclosure also provides a detector configured to receive a signal from a DC-coupled circuit; determine the trough extremes of the signal; and determine the pulse distribution in the signal based on the trough extremes.

[0182] The specific steps for the detector to determine the extreme values ​​of the signal troughs and, based on these extreme values, to determine the pulse distribution in the signal can be found in the aforementioned embodiments, and will not be repeated here.

[0183] In some embodiments, the detector may include at least one of an integrated circuit with processing capabilities, or a processor. For example, the processor may be a central processing unit (CPU), a microprocessor, or a field-programmable gate array (FPGA).

[0184] Figure 18 shows an example diagram of a detector consistent with some embodiments of this disclosure. Referring to Figure 18, the detector T includes a memory T0 and a processor T1.

[0185] In some embodiments, the memory T0 may be a device or circuit with storage function. For example, the memory T0 may be a read-only memory (ROM) or other types of static storage devices capable of storing static information and instructions. For example, the memory T0 may be a random access memory (RAM) or other types of dynamic storage devices capable of storing information and instructions. As another example, the memory T0 may be an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM), or other optical disc storage, optical disk storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media, or other magnetic storage devices.

[0186] In some embodiments, the processor T1 may be a central processing unit (CPU), a microprocessor, or a field programmable gate array (FPGA), etc.

[0187] In some embodiments, the processor T1 may be a circuit with signal processing capabilities.

[0188] The detectors using some embodiments of this disclosure can determine the trough extreme values ​​of the received signal from the DC-coupled circuit, and then determine the pulse distribution in the signal based on the trough extreme values. The detectors have good signal processing performance and simple structure.

[0189] This disclosure also provides a lidar, including:

[0190] The detector is configured to receive a signal from a DC-coupled circuit; determine the trough extrema of the signal; and determine the pulse distribution in the signal based on the trough extrema.

[0191] In some embodiments, the detector may include at least one of an integrated circuit with processing capabilities, or a processor. For example, the processor may be a central processing unit (CPU), a microprocessor, or a field-programmable gate array (FPGA).

[0192] The lidar employing some embodiments of this disclosure determines the extreme values ​​of the troughs in the received signal from the DC-coupled circuit using a detector, thereby determining the pulse distribution in the signal. Based on the determined pulse distribution, the lidar can acquire accurate signal processing results, thus improving the accuracy of the measurement results.

[0193] This disclosure also provides a computer program product, including computer instructions, wherein when executed by a processor, the computer instructions implement the method for detecting pulses according to any of the foregoing embodiments. Specific steps can be found in the foregoing embodiments, and will not be repeated here.

[0194] This disclosure also provides a non-volatile computer-readable storage medium storing computer instructions thereon, wherein the computer instructions, when executed by a processor, implement the method for detecting pulses according to any of the foregoing embodiments. Specific steps can be found in the foregoing embodiments, and will not be repeated here.

[0195] In some embodiments, the non-volatile computer-readable storage medium may be various suitable readable storage media such as optical discs, hard disk drives, solid-state drives, etc.

[0196] The foregoing has described specific embodiments of this application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0197] In summary, after reading this detailed disclosure, those skilled in the art will understand that the foregoing detailed disclosure is presented by way of example only and is not restrictive. Although not explicitly stated herein, those skilled in the art will understand that the requirements of this application encompass various reasonable changes, improvements, and modifications to the embodiments. These changes, improvements, and modifications are intended to be made by this application and are within the spirit and scope of the exemplary embodiments of this application.

[0198] Furthermore, certain terms used in this application have been used to describe embodiments of this application. For example, "an embodiment," "an embodiment," and / or "some embodiments" mean that a particular feature, structure, or characteristic described in connection with that embodiment may be included in at least one embodiment of this application. Therefore, it is to be emphasized and understood that two or more references to "an embodiment" or "an embodiment" or "alternative embodiment" in various parts of this application do not necessarily refer to the same embodiment. Moreover, specific features, structures, or characteristics may be appropriately combined in one or more embodiments of this application.

[0199] It should be understood that in the foregoing description of the embodiments of this application, various features are combined in a single embodiment, drawing, or description for the purpose of simplifying the understanding of a feature. However, this does not mean that the combination of these features is necessary, and those skilled in the art may readily identify some of the devices as separate embodiments when reading this application. That is, the embodiments in this application can also be understood as an integration of multiple sub-embodiments. It is also valid when each sub-embodiment contains fewer than all the features of a single foregoing disclosed embodiment.

[0200] Every patent, patent application, publication of a patent application, and other material such as articles, books, specifications, publications, documents, articles, etc., cited herein, except for any related historical prosecution documents, any identical ones that may be inconsistent with or conflict with this document, or any identical historical prosecution documents that may have a limiting effect on the widest scope of the claims, may be incorporated herein by reference and used for all purposes now or hereafter in connection with this document. Furthermore, in the event of any inconsistency or conflict between the description, definition, and / or use of terms related to any included material and those related to this document, the terminology used herein shall prevail.

[0201] Finally, it should be understood that the embodiments disclosed herein are illustrative of the principles of the embodiments of this application. Other modified embodiments are also within the scope of this application. Therefore, the embodiments disclosed herein are merely examples and not limitations. Those skilled in the art can adopt alternative configurations to implement the applications in this application based on the embodiments in this application. Therefore, the embodiments of this application are not limited to the embodiments precisely described in the application.

Claims

1. A photodetector, characterized by, Comprising: N detectors, the N detectors comprising a detector; the detector is configured to receive a light signal and output an electrical signal, and N is an integer greater than 1; a signal processing circuit connected to the N detectors in a direct current coupling manner and configured to collect the electrical signal; and a switch group connected to the N detectors and the signal processing circuit and configured to turn on a target detector and the signal processing circuit, wherein the target detector comprises one or more of the N detectors.

2. The light detector of claim 1, wherein the N detectors comprise M detector groups, the M detector groups comprising a detector group; the detector group comprises a first connection end and one or more detectors, and M is an integer less than N; each of the one or more detectors comprises a first end and a second end; wherein, in the detector group, the first end of the one or more detectors is connected to the first connection end, and the second end of the one or more detectors is connected to the signal processing circuit through the switch group. The detector group includes a target detector, and the switch group includes:

3. The photodetector of claim 2, wherein, a first switch group configured to turn on the target detector in the detector group and the signal processing circuit. The switch group further comprises:

4. The photodetector of claim 3, wherein, a second switch group comprising P second switches, wherein each of the P second switches is connected to a different detector group, and P is an integer less than or equal to M; the P second switches are configured to output a first target voltage to the different first connection ends of the detector groups. The P second switches adjust the first target voltage of the detector groups connected thereto to an operating voltage at different times.

5. The photodetector of claim 4, wherein, The P second switches include a second switch, and the second switch includes:

6. The photodetector of claim 5, wherein, a first input end receiving a first voltage; a second input end receiving a second voltage; an output end outputting the first voltage or the second voltage according to a control signal; and a control end receiving the control signal, the control signal switching between a first level and a second level; wherein the first target voltage comprises the first voltage and the second voltage. The light detector further comprises a level adjustment circuit, and the second switch is connected to the level adjustment circuit, wherein 7. The photodetector of claim 6, wherein, the level adjustment circuit is connected to the control end and the second input end and is configured to output a control signal based on the second voltage. The light detector further comprises a voltage ramping circuit; 8. The photodetector of claim 6, wherein, the voltage ramping circuit is connected between the output end of the second switch and the first connection end of the detector group and is configured to receive a voltage at the output end and output the first target voltage to the first connection end, the voltage ramping circuit is configured to control the speed of changing the first target voltage to the operating voltage when the voltage value at the output end jumps. Further comprising a bias voltage end for receiving a bias voltage; 9. The photodetector of claim 3, wherein, different detectors in the detector group are connected to the bias voltage end through different first resistors. The switch group further comprises:

10. The photodetector of claim 9, wherein, ​ a third switch group comprising a plurality of third switches, the plurality of third switches comprising a third switch; the third switch being connected with the detector and the first resistor corresponding to the detector; wherein different detectors in the detector group are connected with different third switches.

11. The photodetector of claim 10, wherein, The third switch comprises a transistor.

12. The photodetector of claim 10, wherein, The light detector further comprises a third voltage terminal for receiving a third voltage, a difference between a voltage of the first terminal of the detector group and the third voltage being less than a breakdown voltage of the detector; The second terminal of different detectors of the same detector group are connected to the third voltage through different second resistors.

13. The photodetector of claim 10, wherein, The light detector further comprises a second voltage supply circuit, the second voltage supply circuit being connected with the first resistor and the signal processing circuit, and being configured to provide a base voltage to the signal processing circuit.

14. A lidar, comprising: comprising: a signal transmitter configured to transmit a detection signal; and the light detector of any one of claims 1-13.

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