WO2022126394A1

WO2022126394A1 - Current limiting protection circuit, current limiting protection method, and device

Info

Publication number: WO2022126394A1
Application number: PCT/CN2020/136617
Authority: WO
Inventors: 谭斌; 江申
Original assignee: 深圳市速腾聚创科技有限公司
Priority date: 2020-12-15
Filing date: 2020-12-15
Publication date: 2022-06-23
Also published as: CN114946041A

Abstract

Disclosed in embodiments of the present application are a current limiting protection circuit, a current limiting protection method, and a device. The current limiting protection circuit comprises a power source, a first photoelectric sensor, a receiving and outputting circuit, a current limiting protection circuit, and a controller, wherein the current limiting protection circuit is used for receiving an initial voltage signal and amplifying same to obtain a negative bias signal, and loading the negative bias signal to an anode of the first photoelectric sensor to decrease the current value of the first photoelectric sensor. By using the embodiments of the present application, the working current of the photoelectric sensor can be limited, thereby preventing the photoelectric sensor from working abnormally or even being damaged due to excessive current, and remarkably improving the reliability of working of the photoelectric sensor in the case of receiving highly reflective energy.

Description

A current limiting protection circuit, current limiting protection method and device

technical field

The present application relates to the field of electronic circuits, and in particular, to a current-limiting protection circuit, a current-limiting protection method and device.

Background technique

The single-photon array sensor is composed of multiple single-photon avalanche diodes with a gain of more than 106 times. It can detect very low-power optical signals and is suitable for use in laser ranging radar. In the process of using the single-photon array sensor for ranging, when the reflected energy is high, the single-photon array sensor frequently excites the micro-unit to work, the current changes greatly, and the single-photon array sensor is abnormally heated. , resulting in abnormal operation or even damage to the single-photon array sensor, resulting in the failure of lidar ranging.

In view of this, there is an urgent need to propose a working circuit containing a single-photon array sensor to solve the problems that occur when the above-mentioned optical single-photon array sensor works. Realize the possibility of laser ranging radar ranging under the condition of receiving high reflected energy.

SUMMARY OF THE INVENTION

The embodiments of the present application provide a current-limiting protection circuit, a current-limiting protection method and a device, which can limit the working current of the photoelectric sensor, thereby preventing the photoelectric sensor from working abnormally or even being damaged due to excessive working current, and significantly improving the performance of receiving high reflection Reliability of photoelectric sensor operation in the presence of energy. The technical solution is as follows:

In a first aspect, the present application proposes a current-limiting protection circuit, including: a power supply, a first photoelectric sensor, a receiving output circuit, a current-limiting protection circuit, and a controller;

The first end of the power supply is connected to the cathode of the first photoelectric sensor, the first end of the controller is connected to the current limiting protection circuit, and the second end of the controller is connected to the receiving output circuit , the third end of the controller is connected to the second end of the power supply, the anode of the first photoelectric sensor is connected to the receiving output circuit, and the current limiting protection circuit is connected to the anode of the first photoelectric sensor connected;

the power supply for providing a positive bias signal for the first photoelectric sensor;

The receiving and outputting circuit is configured to receive the first echo signal collected by the first photoelectric sensor, and send the first echo signal to the controller;

the controller, configured to analyze and obtain a signal characteristic value after receiving the first echo signal, and output an initial voltage signal based on the signal characteristic value;

The current limiting protection circuit is used for amplifying the initial voltage signal to obtain a negative bias signal, and loading the negative bias signal to the anode of the first photoelectric sensor to reduce the first The current value of the photoelectric sensor.

In a second aspect, the present application provides a current-limiting protection method, and the current-limiting protection method is applied to the current-limiting protection circuit described in the first aspect;

Wherein, the method includes:

outputting a driving voltage signal to the current limiting protection circuit;

Receive the first echo signal from the receiving output circuit, analyze the first echo signal to obtain a signal characteristic value; wherein, the first echo signal is obtained by the receiving output circuit through the first photoelectric sensor of;

Based on the signal characteristic value, output the initial voltage signal to the current limiting protection circuit; wherein, the initial voltage signal is used to instruct the current limiting protection circuit to output a negative bias signal and load it into the first photoelectric the anode of the sensor to reduce the current value of the first photosensor.

In a third aspect, the present application provides a current limiting protection device, the current limiting protection device is applied to the current limiting protection method according to the second aspect, and the current limiting protection device includes:

an output module, which outputs a driving voltage signal to the current limiting protection circuit;

a receiving module, receiving the first echo signal from the receiving output circuit, and analyzing the first echo signal to obtain a signal characteristic value; wherein, the first echo signal is passed by the receiving output circuit through the first echo signal Obtained by photoelectric sensor;

a comparison module, outputting the initial voltage signal to the current-limiting protection circuit based on the signal characteristic value; wherein the initial voltage signal is used to instruct the current-limiting protection circuit to output a negative bias signal and load it into the current-limiting protection circuit the anode of the first photosensor to reduce the current value of the first photosensor.

In a fourth aspect, the present application provides a computer storage medium, the computer storage medium stores a plurality of instructions, and the instructions are suitable for being loaded by a processor and performing the method steps of the third aspect.

In a fifth aspect, the present application provides a lidar, including the current limiting protection circuit described in the first aspect.

The beneficial effects brought by the technical solutions provided by some embodiments of the present application at least include: using a current-limiting protection circuit to limit the working current of the photoelectric sensor, thereby preventing the photoelectric sensor from heating due to excessive operating current, thereby causing the photoelectric sensor to work abnormally Even damaged; significantly improve the reliability of the photoelectric sensor in the case of receiving high reflected energy, and improve the distance measurement ability of the photoelectric sensor.

Description of drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

1 is a schematic diagram of a connection of a current limiting protection circuit provided by an embodiment of the present application;

2 is a schematic diagram of the connection of another current limiting protection circuit provided by an embodiment of the present application;

3 is a schematic diagram of the connection of another current limiting protection circuit provided by an embodiment of the present application;

4 is a schematic flowchart of a current limiting protection method provided by an embodiment of the present application;

FIG. 5 is a schematic structural diagram of a current limiting protection device provided by an embodiment of the present application.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

In the description of the present application, it should be understood that the terms "first", "second" and the like are used for descriptive purposes only, and should not be construed as indicating or implying relative importance. In the description of the present application, it should be noted that, unless otherwise expressly specified and defined, "including" and "having" and any modifications thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but optionally also includes unlisted steps or units, or optionally also includes For other steps or units inherent to these processes, methods, products or devices. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood in specific situations. In addition, in the description of this application, unless otherwise specified, "a plurality" is

means two or more. "And/or", which describes the association relationship of the associated objects, means that there can be three kinds of relationships, for example, A and/or B, which can mean that A exists alone, A and B exist at the same time, and B exists alone. The character "/" generally indicates that the associated objects are an "or" relationship.

The present application will be described in detail below with reference to specific embodiments.

As shown in FIG. 1, a schematic diagram of the connection of a current limiting protection circuit provided by an embodiment of the present application includes: a power supply 101, a first photoelectric sensor L1, a receiving output circuit 103, a current limiting protection circuit 104, and a controller 102; a power supply The first end of 101 is connected to the cathode of the first photoelectric sensor L1, the first end of the controller 102 is connected to the current limiting protection circuit 104, the second end of the controller 102 is connected to the receiving output circuit 103, and the The third end is connected to the second end of the power supply 101, the anode of the first photoelectric sensor L1 is connected to the receiving output circuit 104, and the current limiting protection circuit 103 is connected to the anode of the first photoelectric sensor L1.

The first photoelectric sensor L1, especially referred to as a single-photon array sensor in this application, can be understood as a single-photon avalanche photodiode used in laser communication, which utilizes the avalanche multiplication effect of carriers to amplify the photoelectric signal to improve detection efficiency. sensitivity. For example, the models of the first photoelectric sensor L1 include, but are not limited to, C30659-900-R5BH, C30659-1550-R08BH, C30919E, and the like. Taking a high-sensitivity SiPM (silicon photomultiplier tube) as an example of the first photosensor L1, the SiPM is composed of a plurality of micro-units in parallel, and each micro-unit is composed of a single-photon avalanche diode (SPAD) and a quenching resistor. When a reverse bias voltage is applied to the silicon photomultiplier tube (the reverse bias voltage generated under the combined action of the positive bias signal and the negative bias signal, several tens of volts), the SPAD depletion layer of each micro-unit has an intensity At a very high electric field, if photons are irradiated from the outside world, Compton scattering will occur with the electron-hole pair in the SPAD semiconductor to generate electrons or holes. The high-energy electrons and holes are then accelerated in the electric field and excited. A large number of secondary electrons and holes, that is, the avalanche effect occurs. At this time, the current output by each micro-unit suddenly increases, the voltage on the quenching resistor also increases, and the electric field in the SPAD decreases instantaneously, that is, the SPAD outputs a The avalanche stops after a momentary current pulse, so the SiPM array can act as a photosensor, converting the light signal into a current signal.

In other words, the laser signal emitted by the lidar is reflected on the target object to form a laser echo signal, the first photoelectric sensor L1 receives the laser echo signal, and the bias voltage formed by the power supply 101 and the current limiting protection circuit 104 is greater than When the breakdown voltage is reached, the laser echo signal is converted into a first current signal, and the first current signal is sent to the receiving output circuit 103 for processing to obtain the first echo signal.

The power supply 101 can be understood as a component that controls to load a positive bias signal on the cathode of the first photosensor L1 based on a preset rule. Preferably, the power supply 101 used in this application is a high-voltage pulse power supply, which can be understood as adding a switch circuit on the basis of a high-voltage DC power supply, so that the output pulse amplitude can be adjusted, the pulse width can be adjusted, the pulse frequency can be adjusted, and the pulse output can be adjusted. A high-voltage power supply with a settable number.

The controller 102 can be implemented by using an FPGA (field programmable gate array, Fieldprogrammable gate array) or an ASIC (Application Specific Integrated Circuit, application specific integrated circuit). Among them, the field programmable gate array is a program-driven logic device, just like a microprocessor, its control program is stored in the memory, and after power-on, the program is automatically loaded into the chip for execution. Field programmable gate array is generally composed of two programmable modules and storage SRAM. CLB is a programmable logic block, the core component of the field programmable gate array, and the basic unit for realizing logic functions. It is mainly composed of digital logic circuits such as logic function generators, flip-flops, and data selectors. Among them, all interface modules (including control modules) of ASIC chip technology are connected to a matrix backplane, and communication between multiple modules can be carried out at the same time through direct forwarding from ASIC chip to ASIC chip; the cache of each module is only It handles the input and output queues on this module, so the performance requirements of the memory chip are much lower than those of the shared memory method. In short, the switch matrix is characterized by high access efficiency, suitable for simultaneous multi-point access, easy to provide very high bandwidth, and easy performance expansion, not easily limited by CPU, bus and memory technology.

In the embodiment of the present application, the controller 102 is configured to receive the first echo signal of the receiving and outputting circuit 103 to obtain the signal characteristic value after analysis, and output an initial voltage signal to the current limiting protection circuit 104 based on the signal characteristic value. The signal characteristic value may be a current value or a voltage value of the first echo signal. For example, the first echo signal is analyzed to obtain a voltage value. When the voltage value is greater than the voltage threshold, an initial voltage signal is output to the current limiting protection circuit 104 .

The receiving and outputting circuit 103 can be understood as receiving the first current signal of the first photoelectric sensor L1, performing noise reduction, amplification and other processing on the current signal to obtain a first echo signal, and sending the first echo signal to the controller 102 circuit.

In one embodiment, the receiving output circuit 103 includes: a transimpedance amplifying circuit and a processing circuit; and a transimpedance amplifying circuit, connected to the first photosensor L1, for converting the first current signal into a first voltage signal and amplifying it processing to obtain the amplified voltage signal; the processing circuit, connected with the transimpedance amplifying circuit, is used for receiving the amplified voltage signal, and sending the first echo signal obtained after the voltage signal passes through the analog-to-digital converter to the controller 102. It can be understood that the current value of the first current signal generated by the first photoelectric sensor L1 according to the laser echo signal is relatively small, so it needs to be converted into the first voltage signal by the transimpedance amplifier circuit, and then amplified and shaped to facilitate the processing circuit. signal processing.

The current limiting protection circuit 104 can be understood as being used to amplify the initial voltage signal based on a preset operation rule to obtain a negative bias signal, and load the negative bias signal to the anode of the first photoelectric sensor L1 to reduce the first photoelectric Protection circuit for the current value of sensor L1.

For example, the working process of the current limiting protection circuit of the present application is as follows: the first photosensor L1 is composed of a high-sensitivity SiPM (silicon photomultiplier tube), and an avalanche effect occurs when photons are received. The current output by each micro-unit suddenly increases, the current value and the number of photons are linearly positively correlated, and the photoelectric amplification capability (ie Gain, Gain) is positively correlated with the bias voltage (Bias Voltage); at time T1, the controller 102 moves to the limit The current protection circuit 104 outputs the driving voltage signal V ₁ , and the current limiting protection circuit 104 receives the driving voltage signal V ₁ and amplifies it to obtain a negative bias signal V _m , which is loaded on the anode of the first photoelectric sensor L1; The sensor L1 outputs the current value I _a of the first current signal, the receiving and outputting circuit 103 receives the first current signal and processes it to obtain a first echo signal, the voltage value is _VL , and the first echo signal _VL It is transmitted to the controller 102; the controller 102 receives the first echo signal _VL , analyzes the voltage value _VL as the signal characteristic value, and compares it with the voltage threshold V ₀ ; when the voltage value of the first echo signal _VL > voltage Threshold V ₀ , the controller 102 outputs an initial voltage signal V ₂ to the current-limiting protection circuit 104 , wherein the voltage value V ₂ of the initial voltage signal > the voltage value V ₁ of the driving voltage signal; the current-limiting protection circuit 104 receives the initial voltage signal V After ₂ , the amplification process is performed to obtain the negative bias signal _Vn , which is loaded on the anode of the first photosensor L1. Since the positive bias signal _Vd loaded by the power supply 101 on the first photosensor L1 does not change, the first photosensor L1 The bias voltage of L1 decreases, the photoelectric amplification capability decreases (ie the gain decreases), and the current value of the current _Ia of the first photoelectric sensor L1 decreases.

The beneficial effects brought by the technical solutions provided by some embodiments of the present application at least include: using a current-limiting protection circuit to limit the working current of the photoelectric sensor, thereby preventing the photoelectric sensor from heating due to excessive operating current, thereby causing the photoelectric sensor to work abnormally Even damage; significantly improve the reliability of the photoelectric sensor in the case of receiving high reflected energy, such as the reliability of the object with high reflectivity or the object is very close, and improve the distance measurement ability of the photoelectric sensor.

As shown in FIG. 2 , a schematic diagram of connection of another current limiting protection circuit provided by an embodiment of the present application includes: a power supply 101 , a first photoelectric sensor L1 , a second photoelectric sensor L2 , a first capacitor C1 , and a second capacitor C2 , a processing circuit 202, a transformer 201, a current limiting protection circuit 104 and a controller 102; wherein, the transformer 201 includes a primary coil and a secondary coil.

The first end of the controller 102 is connected to the first end of the power supply 101, the second end of the power supply 101 is connected to the cathode of the first photoelectric sensor L1, the third end of the power supply 101 is connected to the cathode of the second photoelectric sensor L2, the first The anode of the photosensor L1 is connected to the first end of the first capacitor C1, the second end of the first capacitor C1 is grounded, the anode of the first photosensor L1 is connected to the primary coil of the transformer 201, and the anode of the second photosensor L2 is connected to the primary coil of the transformer 201. The first end of the second capacitor C2 is connected to the ground, the anode of the second photoelectric sensor L2 is connected to the primary coil of the transformer 201 , and the second end of the controller 102 is connected to the current limiting protection circuit 104 , the current limiting protection circuit 104 is connected to the primary coil of the transformer 201 , the secondary coil of the transformer 201 is connected to the processing circuit 202 , and the processing circuit 202 is connected to the third end of the controller 102 .

The second photoelectric sensor L2, especially referred to as a single-photon array sensor in this application, can be understood as an avalanche photodiode used in laser communication, which utilizes the avalanche multiplication effect of carriers to amplify the photoelectric signal to improve detection sensitivity.

In the embodiment of the present application, the first photosensor L1 and the second photosensor L2 are further provided with a decoupling circuit, and the decoupling circuit includes a first capacitor C1 and a second capacitor C2. The first end of the first capacitor C1 is connected to the anode of the first photoelectric sensor L1, the second end of the first capacitor C1 is connected to the ground (such as the casing), and the first end of the second capacitor C2 is connected to the second photoelectric sensor L2. The anode is connected, the second end of the second capacitor C2 is connected to the ground (such as the casing), and the first capacitor C1 and the second capacitor C2 are used as decoupling capacitors for removing power supply noise and stabilizing the bias voltage.

In the embodiment of the present application, the second photoelectric sensor L2 is provided with a shading member, which is used for shading the second photoelectric sensor L2, and may be, but not limited to, a shading plate, a shading cover, or a shading cloth. It can be understood that, in the absence of light, when the applied bias voltage is greater than the breakdown voltage, the second light sensor L2 will also output a second current signal.

The working principle of the second photoelectric sensor L2 in the embodiment of the present application is described below. The current signal caused by the laser echo signal on the first photosensor L1 is called the photocurrent signal, and the current signal caused by the bias voltage provided by the power supply is called the bias current signal. Therefore, the first current signal output by the first photosensor L1 may only include the bias current signal at most of the time, and at the moment when the laser echo signal reaches the first photosensor L1, the first current signal includes the photocurrent signal and bias current signal. Meanwhile, the photocurrent signal is weaker than the bias current signal, so it is difficult for the processing circuit 202 and even the controller 102 to detect the photocurrent signal.

Because the second photosensor L2 is connected in parallel with the first photosensor L1, and the same bias voltage is provided by the same power supply 101 and the controller 102, the bias voltage of the second photosensor L2 is the same as that of the first photosensor L1. The voltages are equal, that is, the bias current signals of the second photosensor L2 and the first photosensor L1 are the same. Meanwhile, because the second photosensor L2 is in a light-shielding state, the second current signal output by the second photosensor L2 is a bias current signal at any time. Therefore, the transformer 201 receives the first echo signal of the first photoelectric sensor L1 and the second echo signal of the second photoelectric sensor L2, performs differential processing, and removes the current value belonging to the second echo signal in the first echo signal. , the differential current signal is obtained. The differential current signal obtained by the processing circuit 202 is only the photocurrent part. Therefore, the differential current signal obtained by the processing circuit 202 is a photocurrent signal when the laser echo signal reaches the first photosensor L1, and the differential current signal should be 0 outside the moment when the laser echo signal reaches the first photosensor L1.

The beneficial effects brought by the technical solutions provided by some embodiments of the present application at least include: Therefore, the processing circuit 202 and even the controller 102 can sensitively detect the photocurrent signal, and detect the moment when the differential current signal obtained by the processing circuit 202 is not 0 , as the moment when the laser echo signal reaches the first photoelectric sensor L1; the sensitivity and accuracy of detecting the laser echo signal are improved, and the accuracy of ranging is improved.

The transformer 201 can be understood as receiving the first echo signal of the first photoelectric sensor L1 and the second echo signal on the second photoelectric sensor L2, performing differential processing to obtain a differential current signal, and using the principle of electromagnetic induction to convert the differential current signal. A component that amplifies the voltage value. Preferably, a balun transformer is used in the present application, that is, an unbalanced transformer with functions of balanced transmission, unbalanced transmission and impedance transformation, which is used for twisted pair wires.

The processing circuit 202 can be understood as a circuit that collects the differential current signal through the transformer 201 , processes the differential current signal to obtain a differential voltage signal, and transmits the differential voltage signal to the controller 101 .

It should be noted that there are at least two ways to realize the receiving and outputting circuit 103: one is to first perform differential processing on the first echo signal and the second echo signal on the first photoelectric sensor L1 and the second photoelectric sensor L2, Then transimpedance amplification, that is, the implementation provided by the above-mentioned embodiment of the present application; the other is to first amplify the first echo signal and the second echo signal by transimpedance, and then amplify the first echo signal and the second echo signal. Doing differential processing is the second implementation. Since the second embodiment will limit the effective dynamic range of the signal chain and increase power consumption and cost, the present invention adopts the first embodiment to realize the receiving and outputting circuit 103 .

The beneficial effects brought by the technical solutions provided by some embodiments of the present application at least include: in this embodiment, a balun transformer with low insertion loss and high symmetry can be selected, that is, a balun transformer with small signal attenuation and good cancellation processing performance, so The photocurrent signal range close to the output of a single photoelectric sensor can be obtained; it mainly increases the thermal noise of the matching resistor RT, which is much smaller than the current noise of the transimpedance amplification circuit itself (this noise exists in the transimpedance amplification process), and the photocurrent signal The influence of the signal-to-noise ratio is basically negligible; only a very small thermal noise is added, while the photocurrent signal is basically not weakened, and the influence on the signal-to-noise ratio is small, and the photocurrent signal amplification ability of the circuit is almost not reduced.

In another embodiment, the implementation of the receiving output circuit 103 may be: the first echo signal and the second echo signal output by the first photosensor L1 and the second photosensor L2 are respectively input to a transimpedance amplifier for first-stage amplification , output the amplified first echo signal and the second echo signal, and then input the amplified first echo signal and the second echo signal into the subtractor, output the differential voltage signal, and then perform the secondary enlarge.

For example, the working process of the current limiting protection circuit of the present application is as follows: the first photosensor L1 is composed of a high-sensitivity SiPM (silicon photomultiplier tube), and an avalanche effect occurs when photons are received. The current output by each micro-unit suddenly increases, the current value and the number of photons are linearly positively correlated, and the photoelectric amplification capability (ie Gain, Gain) is positively correlated with the bias voltage (Bias Voltage); at time T1, the controller 101 moves to the limit The current protection circuit 104 outputs the driving voltage signal V ₁ , and the current limiting protection circuit 104 receives the driving voltage signal V ₁ and amplifies it to obtain a negative bias signal V _m , which is loaded on the first photoelectric sensor L1 and the second photoelectric sensor L2 On the anode; the first photoelectric sensor L1 outputs the first echo signal I _a , the second photoelectric sensor L2 outputs the second echo signal I _b under the action of the bias voltage; the processing circuit 202 receives the differential current signal I through the transformer 201 _c , where I _c =I _a -I _b , convert the differential current signal I _c into a voltage signal and amplify it to obtain a differential voltage signal V _c , and output the differential voltage signal V _c to the controller 102 ; the controller 102 receives When the differential voltage signal V _c is compared with the voltage threshold V ₀ , and the voltage value of the differential voltage signal V _c > the voltage threshold V ₀ , the controller 101 outputs the initial voltage signal V ₂ to the current limiting protection circuit 104 , wherein the initial voltage signal V ₂ > driving voltage signal V ₁ ; the current-limiting protection circuit 104 receives the initial voltage signal V ₂ and amplifies it to obtain a negative bias signal V _n , which is loaded on the anodes of the first photosensor L1 and the second photosensor L2 , since the positive bias signal V _d loaded by the power supply 101 on the first photosensor L1 does not change, the bias voltage of the first photosensor L1 decreases, and the photoelectric amplification capability decreases (ie, the gain decreases), and the first photosensor L1 The current value of the current I _a becomes smaller.

As shown in FIG. 3 , a schematic diagram of the connection of another current limiting protection circuit provided by an embodiment of the present application includes: a power supply 101 , a first photoelectric sensor L1 , a second photoelectric sensor L2 , a first capacitor C1 , and a second capacitor C2 , a processing circuit 202, a transformer 201, a current limiting protection circuit 104 and a controller 102; wherein, the transformer 201 includes a primary coil and a secondary coil.

The current limiting protection circuit 104 includes: a digital-to-analog converter 1041, a high-voltage amplifier U1, a first resistor R1 and a third capacitor C3.

The inverting input terminal of the high voltage amplifier U1 is connected to the primary coil of the transformer 103, the output terminal of the high voltage amplifier U1 is connected to the first terminal of the first resistor R1, and the first terminal of the first resistor R1 is connected to the first terminal of the third capacitor C3. The second end of the first resistor R1 is connected to the second end of the third capacitor C3, the input end of the digital-to-analog converter 1041 is connected to the second end of the controller 102, and the output end of the digital-to-analog converter 1041 is connected to the high voltage The non-inverting input of amplifier U1 is connected.

The receiving output circuit 103 includes: a transformer 201 , a transimpedance amplifier 301 , an amplification conditioning circuit 302 and an analog-to-digital converter 303 .

The transimpedance amplifier 301 is connected to the secondary coil of the transformer 201, the amplifying and conditioning circuit 302 is connected to the transimpedance amplifier 301, the digital-to-analog converter 303 is connected to the amplifying and conditioning circuit 302, and the second end of the controller 102 is connected to the digital-to-analog converter 303.

The digital-to-analog converter 1041 (DAC, D/A converter) can be understood as a device that converts discrete digital signals into continuous analog signals, mainly composed of digital registers, analog electronic switches, bit weight networks, summing operational amplifiers and The reference voltage source (or constant current source) is composed. For example, the models of the digital-to-analog converter 1041 include, but are not limited to, models such as DAC7311IDCKR, DAC7311IDCKR, and the like.

In the embodiment of the present application, the digital-to-analog converter 1041 is configured to perform digital-to-analog conversion after receiving the initial voltage signal of the controller 102 to obtain the converted voltage signal, and output the converted voltage signal to the high-voltage amplifier U1.

In another embodiment, the current-limiting protection circuit 104 does not include the digital-to-analog converter 1041, and the second terminal of the controller 102 is connected to the non-inverting input terminal of the high-voltage amplifier U1. In this embodiment, the initial voltage signal output by the second end of the controller 102 is a modulo electrical signal, which can be directly received by the high-voltage amplifier U1.

The high-voltage amplifier U1 can be understood as a signal amplifier with high-voltage amplitude output, which is used for receiving the converted voltage signal from the digital-to-analog converter 1041 and performing amplification processing based on a preset operation rule to obtain a negative bias signal, which passes through the first resistor. After R1 is limited, it is loaded on the anode of the first photoelectric sensor L1. For example, the voltage value of the converted voltage signal loaded on the non-inverting input terminal of the high voltage amplifier U1 is 5V, and the negative bias voltage signal of 200V is output and loaded on the anode of the first photosensor L1.

In the embodiment of the present application, a third capacitor C3 is connected in parallel with both ends of the first resistor R1. It should be noted that when a photon is incident, the incident photon can be effectively absorbed by a large number of single-photon avalanche diodes and excite the avalanche effect, so that a large number of single-photon avalanche diodes can be turned on and output pulse current; The capacitor C _cell (due to the structure of the silicon photomultiplier tube, each single-photon avalanche diode is connected with an equivalent capacitor in parallel) is charged, so that the equivalent capacitor of the avalanche diode is charged, thereby returning to the normal bias state, waiting for Before the charging of the effective capacitor is completed, it is difficult for the silicon photomultiplier tube to effectively detect the incident light and output the current; in the embodiment of the present application, the equivalent capacitance refers to the first capacitor C1 and the second capacitor C2, wherein the equivalent capacitance C _cell and the quenching The resistance R _q determines the recovery time constant of the microcell, and the time to recover to 90% of the bias voltage is about 2.3 times the time constant, that is, the recovery time can be: T _recovery =2.3×R _q ×C _cell . When there is only the first resistor R1 in the current limiting protection circuit 104, the first resistor R1 and the first capacitor C1 or the second capacitor C2 form an RC circuit. When the bias voltage is greater than the breakdown voltage and the avalanche effect occurs in the first photosensor L1 , the RC circuit will slow down the voltage change of the anode terminal of the first photoelectric sensor L1, and slow down the recovery time of the first photoelectric sensor L1.

The beneficial effects brought by the technical solutions provided by some embodiments of the present application at least include: connecting a third capacitor C3 in parallel with both ends of the first resistor R1, which can store energy when the current value output by the first photoelectric sensor L1 changes rapidly, and can The charge required for the rapid change of the voltage at the anode terminal of the first photosensor L1 is provided to speed up the recovery time of the first photosensor L1.

The trans-impedance amplifier 301 (trans-impedance amplifier, TIA) can be understood as converting the input voltage signal into a current signal that satisfies a certain relationship. The converted current is equivalent to a constant current source with adjustable output, and its output current should be able to maintain Stable without changing with load changes. In the embodiment of the present application, the transimpedance amplifier 301 converts the differential current signal collected by the transformer 201 into a differential voltage signal to be processed through the current and voltage, and outputs the signal to the amplification and conditioning circuit 302 .

The amplification conditioning circuit 302 can be understood as amplifying, buffering or scaling the analog signal from the sensor, making it suitable for the input of an analog-to-digital converter (ADC) and obtaining a digital signal, thereby outputting to the controller, so that the controller can complete the Data acquisition, control processes, perform calculations, display readouts, and other purposes. In the embodiment of the present application, the amplification and conditioning circuit 302 is configured to amplify and condition the differential voltage signal to be processed to obtain a differential voltage signal, and output the differential voltage signal to the analog-to-digital converter 303 .

The analog-to-digital converter 303 (Analog to Digital Converter, A/D converter) can be understood as an electronic component that converts an analog signal into a digital signal, for example, the model of the analog-to-digital converter 303 includes but is not limited to ADS822E, ADS8472IBRGZT and other models. In the embodiment of the present application, the analog-to-digital converter 303 is configured to perform analog-to-digital conversion on the differential voltage signal from the amplification and conditioning circuit 302 to obtain a digital voltage signal, and transmit the digital voltage signal to the controller 102 .

In another embodiment, the receiving and outputting circuit 103 does not include the analog-to-digital converter 303 , and the third end of the controller 102 is connected to the amplifying and conditioning circuit 302 . In this embodiment, the third terminal of the controller 102 can receive the analog signal.

The description of other units in the embodiment of the present application is described with reference to FIG. 2 , and the working process is also described with reference to FIG. 2 .

As shown in FIG. 4 , a schematic flowchart of a current limiting protection method provided in an embodiment of the present application is executed by a controller, and the controller may adopt an FPGA (Field-programmable gate array, Field-programmable gate array) or an ASIC (Application Specific Integrated Circuit, application-specific integrated circuit) implementation. Among them, the field programmable gate array is a program-driven logic device, just like a microprocessor, its control program is stored in the memory, and after power-on, the program is automatically loaded into the chip for execution. Field programmable gate array is generally composed of two programmable modules and storage SRAM. CLB is a programmable logic block, the core component of the field programmable gate array, and the basic unit for realizing logic functions. It is mainly composed of digital logic circuits such as logic function generators, flip-flops, and data selectors. Among them, all interface modules (including control modules) of ASIC chip technology are connected to a matrix backplane, and communication between multiple modules can be carried out at the same time through direct forwarding from ASIC chip to ASIC chip; the cache of each module is only It handles the input and output queues on this module, so the performance requirements of the memory chip are much lower than those of the shared memory method. In short, the switch matrix is characterized by high access efficiency, suitable for simultaneous multi-point access, easy to provide very high bandwidth, and easy performance expansion, not easily limited by CPU, bus and memory technology.

The current limiting protection method proposed in this application includes the following steps:

S401. Output a driving voltage signal to the current limiting protection circuit.

The controller outputs a driving voltage signal to the current-limiting protection circuit, and the current-limiting protection circuit amplifies the initial voltage signal based on a preset operation rule, obtains a negative bias signal, and loads the negative bias signal to the first photoelectric sensor and the second photoelectric The anode of the sensor, the power supply provides a positive bias signal at the cathode of the first photosensor and the second photosensor, so that the bias voltage on the first photosensor and the second photosensor is greater than the breakdown voltage, the first photosensor and the second photosensor. The photoelectric sensor is working normally.

For example, the controller outputs a driving voltage signal V1 to the current-limiting protection circuit 104, and the current-limiting protection circuit 104 receives the driving voltage signal V1 and amplifies it to obtain a negative bias signal _Vm , which is loaded on the first photoelectric sensor and the second photoelectric On the anode of the sensor; the power supply outputs a positive bias signal V _d and is loaded on the cathodes of the first and second photosensors; where V _m <V _d , so on the first and second photosensors A negative bias voltage is formed, and the bias voltage is greater than the breakdown voltage of the first photosensor; when the first photosensor receives photons, a current value is output.

S402. Receive the first echo signal from the receiving output circuit, and analyze the first echo signal to obtain the signal characteristic value.

The receiving and outputting circuit can be understood as a circuit that collects the differential current signal on the first photoelectric sensor and the second photoelectric sensor, processes the differential current signal to obtain a differential voltage signal, and transmits the differential voltage signal to the controller.

In an application example, the implementation of the voltage compensation circuit may be: the first echo signal and the second echo signal output by the first photoelectric sensor and the second photoelectric sensor are respectively input to both ends of the balanced side of the balun transformer, and the differential processing is performed. The obtained differential current signal is coupled to the primary side through a transformer, and then the differential current signal is input to a transimpedance amplifier for transimpedance amplification to obtain a differential voltage signal.

For example, the first photoelectric sensor outputs the first echo signal I _a , and the second photoelectric sensor outputs the second echo signal I _b under the action of the bias voltage; the voltage compensation circuit receives the differential current signal I _c through the transformer, wherein, Ic=Ia-Ib, convert the differential current signal Ic into a differential voltage signal and amplify it to obtain a differential voltage signal V _c , and output the differential voltage signal V _c to the controller; the controller receives the differential voltage signal V _c and performs After analysis, a voltage value of 50V is obtained as the signal characteristic value of the differential voltage _Vc .

S403. Based on the signal characteristic value, output an initial voltage signal to the current limiting protection circuit.

For example, the controller receives the differential voltage signal V _c and compares it with the voltage threshold V ₀ , and the differential voltage signal V _c > the voltage threshold V ₀ , the controller outputs the initial voltage signal V ₂ to the current limiting protection circuit, wherein the initial voltage signal V ₂ > driving voltage signal V ₁ ; the current-limiting protection circuit receives the initial voltage signal V ₂ and amplifies it to obtain a negative bias signal V _n , which is loaded on the anodes of the first photoelectric sensor and the second photoelectric sensor. The negative bias signal V _d loaded by the power supply on the first photoelectric sensor does not change, the bias voltage of the first photoelectric sensor is reduced, the photoelectric amplification capability is reduced (that is, the gain is reduced), and the first echo signal of the first photoelectric sensor is reduced. The current value of I _a becomes smaller.

In one embodiment, the controller outputs an initial voltage signal to the current-limiting protection circuit, including: obtaining a voltage value based on the differential voltage signal, the voltage value being used as a signal characteristic value; calculating an offset between the voltage value and a voltage threshold; based on the offset The voltage value of the initial voltage signal is obtained through the quantity and PID calculation model; the initial voltage signal is output to the current limiting protection circuit.

The PID calculation model is a calculation model that calculates the input value based on the PID control theory to obtain the output value. PID control theory can be understood as a linear control theory in which a control deviation is formed according to a given value and an actual output value, and the deviation is formed by a linear combination of proportional, integral and differential to form a control quantity, and the controlled object is controlled.

For example, the controller receives the differential voltage signal V _c =50V, the voltage threshold V ₀ is 30 V, and the calculation formula of the offset e between the differential voltage signal V _c and the voltage threshold V ₀ is:

e(t)=V _c (t)-V ₀ (t)

The proportional (P), integral (I) and differential (D) of the deviation e are linearly combined to form the basic formula of the PID calculation model. The control law refers to the following formula:

Among them, Kp is the proportional coefficient, Ki is the integral constant, and Kd is the differential constant;

Based on the above rules, the basic formula of the PID calculation model is formed, and the initial voltage signal V ₂ is obtained as 60V. The main parameters in the PID calculation model are determined by the following methods: a tuning method based on the parameter identification of the controlled process object. This method first identifies the parameter model of the object, and then uses the pole configuration tuning method, the cancellation principle method and other theoretical calculations. Tuning method tuning; parameter tuning method based on the output response characteristic of the extracted object, such as ZN parameter tuning method (also called critical proportionality method); parameter optimization method; pattern recognition-based expert system method and controller parameters based on the control behavior of the controller itself Online tuning method, etc.

The above is only a feasible method for the controller to obtain the voltage value of the initial voltage signal based on the voltage value of the differential voltage signal, and the application does not specifically limit the calculation method of the controller.

The following are apparatus embodiments of the present application, which can be used to execute the method embodiments of the present application. For details not disclosed in the device embodiments of the present application, please refer to the method embodiments of the present application.

As shown in FIG. 5 , it is a schematic structural diagram of a current limiting protection device according to an embodiment of the present application. The current limiting protection device can be implemented as a whole or a part of the device through software, hardware or a combination of the two. The current limiting protection device includes an output module 501 , a receiving module 502 and a comparison module 503 .

The output module 501 outputs a driving voltage signal to the current limiting protection circuit;

The receiving module 502 receives a first echo signal from the receiving output circuit, and analyzes the first echo signal to obtain a signal characteristic value; wherein, the first echo signal is passed by the receiving output circuit through the first echo signal. Acquired by a photoelectric sensor;

The comparison module 503, based on the signal characteristic value, outputs the initial voltage signal to the current limiting protection circuit; wherein, the initial voltage signal is used to instruct the current limiting protection circuit to output a negative bias signal and load it into the current limiting protection circuit the anode of the first photoelectric sensor to reduce the current value of the first photoelectric sensor.

An embodiment of the present application further provides a computer storage medium, where the computer storage medium can store multiple instructions, and the instructions are suitable for being loaded by a processor and executing the current limiting protection method shown in FIG. 4 above, For the specific execution process, reference may be made to the specific description of the embodiment shown in FIG. 4 , which will not be repeated here.

The present application also provides a computer program product, the computer program product stores at least one instruction, and the at least one instruction is loaded by the processor to execute the current limiting protection method shown in FIG. For the process, reference may be made to the specific description of the embodiment shown in FIG. 4 , which will not be repeated here.

It should be noted that when the current-limiting protection device provided in the above-mentioned embodiment executes the current-limiting protection method, only the division of the above-mentioned functional modules is used as an example for illustration. Module completion means dividing the internal structure of the device into different functional modules to complete all or part of the functions described above. In addition, the current limiting protection device and the current limiting protection method embodiments provided by the above embodiments belong to the same concept, and the embodiment and implementation process thereof are detailed in the method embodiments, which will not be repeated here.

The above-mentioned serial numbers of the embodiments of the present application are only for description, and do not represent the advantages or disadvantages of the embodiments.

Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be implemented by instructing relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. During execution, the processes of the embodiments of the above-mentioned methods may be included. Wherein, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, or a random storage memory, and the like.

The above disclosures are only the preferred embodiments of the present application, and of course, the scope of the rights of the present application cannot be limited by this. Therefore, equivalent changes made according to the claims of the present application are still within the scope of the present application.

Claims

A sensor protection circuit, characterized by comprising: a power supply, a first photoelectric sensor, a receiving output circuit, a current limiting protection circuit and a controller;

The first end of the power supply is connected to the cathode of the first photoelectric sensor, the first end of the controller is connected to the current limiting protection circuit, and the second end of the controller is connected to the receiving output circuit , the third end of the controller is connected to the second end of the power supply, the anode of the first photoelectric sensor is connected to the receiving output circuit, and the current limiting protection circuit is connected to the anode of the first photoelectric sensor connected;

the power supply for providing a positive bias signal for the first photoelectric sensor;

The receiving and outputting circuit is configured to receive the first echo signal collected by the first photoelectric sensor, and send the first echo signal to the controller;

the controller, configured to analyze and obtain a signal characteristic value after receiving the first echo signal, and output an initial voltage signal based on the signal characteristic value;

The current limiting protection circuit is used for amplifying the initial voltage signal to obtain a negative bias signal, and loading the negative bias signal to the anode of the first photoelectric sensor to reduce the first The current value of the photoelectric sensor.
The sensor protection circuit according to claim 1, further comprising: a second photoelectric sensor; a light shielding element is provided on the second photoelectric sensor;

The third end of the power supply is connected to the cathode of the second photoelectric sensor, and the anode of the second photoelectric sensor is respectively connected to the current limiting protection circuit and the anode of the first photoelectric sensor;

The receiving and outputting circuit is further configured to receive the second echo signal collected by the second photoelectric sensor, process the first echo signal and the second echo signal to obtain a differential voltage signal, and convert the differential voltage signal sent to the controller.
The sensor protection circuit according to claim 1, wherein the current limiting protection circuit comprises: a high-voltage amplifier, a first resistor and a first capacitor;

The second terminal of the controller is connected to the non-inverting input terminal of the high-voltage amplifier, the inverting input terminal of the high-voltage amplifier is connected to the receiving output terminal, and the output terminal of the high-voltage amplifier is connected to the output terminal of the first resistor. The first end is connected, the first end of the first resistor is connected to the first end of the first capacitor, and the second end of the first resistor is connected to the second end of the first capacitor.
The sensor protection circuit according to claim 3, wherein the current limiting protection circuit further comprises: a digital-to-analog converter;

The input end of the digital-to-analog converter is connected to the second end of the controller, and the output end of the digital-to-analog converter is connected to the non-inverting input end of the high-voltage amplifier;

The digital-to-analog converter is configured to perform digital-to-analog conversion after receiving the initial voltage signal of the controller to obtain a converted voltage signal, and output the converted voltage signal to the high-voltage amplifier.
The sensor protection circuit according to claim 2, wherein the receiving and outputting circuit comprises: a transformer and a processing circuit; wherein, the processing circuit comprises a transimpedance amplifier and an amplifier conditioning circuit, and the transformer comprises a primary side coil and a secondary side coil;

The primary coil of the transformer is respectively connected to the anode of the first photoelectric sensor and the anode of the second photoelectric sensor, the secondary coil of the transformer is connected to the transimpedance amplifier, and the amplification conditioning circuit is connected to the The transimpedance amplifier;

the transformer, configured to process the first echo signal and the second echo signal to obtain a differential current signal, and transmit the differential current signal to the transimpedance amplifier;

The transimpedance amplifier is used to convert the differential current signal into a differential voltage signal to be processed through a current and voltage, and output the differential voltage signal to be processed to the amplifying and conditioning circuit;

The amplification and conditioning circuit is used for amplifying and conditioning the differential voltage signal to be processed to obtain a differential voltage signal, and outputting the differential voltage signal to the controller.
The current-limiting protection circuit according to claim 5, wherein the receiving and outputting circuit comprises an analog-to-digital converter;

The analog-to-digital converter is connected to the amplifying and conditioning circuit, and is used for performing analog-to-digital conversion on the differential voltage signal from the amplifying and conditioning circuit to obtain a digital voltage signal, and transmitting the digital voltage signal to the controller .
A current-limiting protection method, wherein the current-limiting protection method is applied to the current-limiting protection circuit of claim 1;

Wherein, the method includes:

outputting a driving voltage signal to the current limiting protection circuit;

Receive the first echo signal from the receiving output circuit, analyze the first echo signal to obtain a signal characteristic value; wherein, the first echo signal is obtained by the receiving output circuit through the first photoelectric sensor of;

Based on the signal characteristic value, output the initial voltage signal to the current limiting protection circuit; wherein, the initial voltage signal is used to instruct the current limiting protection circuit to output a negative bias signal and load it into the first photoelectric the anode of the sensor to reduce the current value of the first photosensor.
A current-limiting protection device, characterized in that, the current-limiting protection device is applied to the current-limiting protection method according to claim 7, and the current-limiting protection device comprises:

an output module, which outputs a driving voltage signal to the current limiting protection circuit;

a receiving module, receiving the first echo signal from the receiving output circuit, and analyzing the first echo signal to obtain a signal characteristic value; wherein, the first echo signal is passed by the receiving output circuit through the first echo signal Obtained by photoelectric sensor;

a comparison module, outputting the initial voltage signal to the current-limiting protection circuit based on the signal characteristic value; wherein the initial voltage signal is used to instruct the current-limiting protection circuit to output a negative bias signal and load it into the current-limiting protection circuit the anode of the first photosensor to reduce the current value of the first photosensor.
A computer storage medium, characterized in that the computer storage medium stores a plurality of instructions, and the instructions are suitable for being loaded by a processor and executing the method steps of any one of claims 1-7.
A lidar, characterized by comprising the current limiting protection circuit according to any one of claims 1-7.