A lidar emission circuit with pulse width compensation and its control method

Abstract

The present application discloses a lidar transmitting circuit with pulse width compensation and its control method. The circuit includes: an optical pulse transmitting circuit and a pulse width sampling control signal feedback circuit. The method includes: generating a start pulse signal and exciting the optical pulse transmitting circuit to output a laser pulse signal according to the start pulse signal; comparing the laser pulse signal with a reference voltage to output a square wave pulse signal; capturing the square wave pulse signal to obtain time interval data; calculating according to the time interval data to obtain the pulse width of the laser pulse current and performing output voltage adjustment processing to obtain a signal feedback amount; and performing feedback adjustment on the output voltage of the optical pulse transmitting circuit according to the signal feedback amount. The embodiments of the present application can achieve the acquisition and adjustment of the pulse width of the optical pulse current, thereby improving the pulse width stability of the optical pulse current. The present application can be widely applied to the technical field of lidar transmitting circuits.

Description

Technical Field

[0001] The present application relates to the technical field of lidar emission circuits, and particularly to a lidar emission circuit with pulse width compensation and its control method. Background Art

[0002] The current lidar emission circuit has the problem of unstable optical pulses. Since the laser will heat up during operation, the parasitic parameters of the laser will change at different temperatures, which causes the pulse width of the optical pulse to change during capacitor discharge. The accuracy that lidar can achieve highly depends on the stability of the emission pulse width. The relevant solutions mainly involve selecting devices with low temperature drift, such as discharge capacitors, lasers, etc., and at the same time strengthening the stability of the power supply voltage. Nevertheless, the temperature drift of the current pulse width of the emission circuit still significantly affects the accuracy performance of the system. There is also a solution that uses peak current detection for certain regulation, but even when the peak currents are the same, the pulse widths of the emission optical pulse currents are still different.

[0003] In summary, the technical problems existing in the related art need to be improved. Summary of the Invention

[0004] The main purpose of the embodiments of the present application is to propose a lidar emission circuit with pulse width compensation and its control method, which can realize the acquisition and adjustment of the pulse width of the optical pulse current, thereby improving the pulse width stability of the optical pulse current.

[0005] To achieve the above object, on the one hand, an embodiment of the present application proposes a lidar emission circuit with pulse width compensation. The circuit includes an optical pulse emission circuit and a pulse width sampling control signal feedback circuit. The pulse width sampling control signal feedback circuit includes a first high-speed comparator module, a second high-speed comparator module, a first time-to-digital converter, a second time-to-digital converter, an MCU module, a digital potentiometer module, and a third resistor. The output end of the optical pulse emission circuit is connected to the input end of the pulse width sampling control signal feedback circuit, and the output end of the pulse width sampling control signal feedback circuit is feedback-connected to the optical pulse emission circuit, where:

[0006] The optical pulse emission circuit is used to output a laser pulse signal;

[0007] The pulse width sampling control signal feedback circuit is used to sample and perform pulse width calculation and judgment processing on the laser pulse signal to generate a signal feedback amount.

[0008] In some embodiments, the optical pulse emission circuit includes a boost circuit and an optical pulse discharge loop. The output end of the boost circuit is connected to the input end of the optical pulse discharge loop, where:

[0009] The boost circuit is used to obtain an input voltage signal and perform a boost process to obtain a capacitor charging voltage;

[0010] The optical pulse discharge circuit is used to perform an adjustment process according to the capacitor charging voltage and output the laser pulse signal.

[0011] In some embodiments, the positive input terminal of the first high-speed comparator module and the positive input terminal of the second high-speed comparator module are respectively connected to the output terminal of the optical pulse emission circuit. The negative input terminal of the first high-speed comparator module is connected to a first reference voltage, and the negative input terminal of the second high-speed comparator module is connected to a second reference voltage. The output terminal of the first high-speed comparator module is connected to the input terminal of the first time-to-digital converter, and the output terminal of the second high-speed comparator module is connected to the input terminal of the second time-to-digital converter. The first time-to-digital converter and the MCU module are interconnected, and the second time-to-digital converter and the MCU module are interconnected. The MCU module and the digital potentiometer module are interconnected. The output terminal of the digital potentiometer module is connected to the input terminal of the third resistor, and the output terminal of the third resistor is connected to the optical pulse emission circuit.

[0012] In some embodiments, it further includes:

[0013] The first high-speed comparator module is used to compare the laser pulse signal with the first reference voltage and sample the rising edge moment of the optical pulse emission circuit;

[0014] The second high-speed comparator module is used to compare the laser pulse signal with the second reference voltage and sample the falling edge moment of the optical pulse emission circuit;

[0015] The first time-to-digital converter is used to calculate the time interval between the start pulse signal and the first stop signal output by the first high-speed comparator module to obtain first time interval data;

[0016] The second time-to-digital converter is used to calculate the time interval between the start pulse signal and the second stop signal output by the second high-speed comparator module to obtain second time interval data;

[0017] The MCU module is used to obtain the first time interval data and the second time interval data and generate a digital potentiometer module voltage adjustment signal;

[0018] The digital potentiometer module is used to perform an output voltage adjustment process according to the digital potentiometer module voltage adjustment signal to obtain the signal feedback amount;

[0019] The third resistor is used to transfer the signal feedback amount to the optical pulse emission circuit.

[0020] To achieve the above object, another aspect of the embodiments of the present application proposes a control method for a lidar emission circuit with pulse width compensation. The method includes the following steps:

[0021] Generate a start pulse signal and stimulate the optical pulse emission circuit to output a laser pulse signal according to the start pulse signal;

[0022] Compare the laser pulse signal with a reference voltage and output a square wave pulse signal, where the square wave pulse signal includes the rising edge time and the falling edge time of the optical pulse emission circuit;

[0023] Capture the square wave pulse signal to obtain time interval data;

[0024] Calculate according to the time interval data to obtain the laser pulse current pulse width and perform output voltage adjustment processing to obtain a signal feedback amount;

[0025] Perform feedback adjustment on the output voltage of the optical pulse emission circuit according to the signal feedback amount.

[0026] In some embodiments, the generating a start pulse signal and stimulating the optical pulse emission circuit to output a laser pulse signal includes:

[0027] Generate the start pulse signal through the MCU module;

[0028] The start pulse signal stimulates the optical pulse emission circuit to output a discharge current;

[0029] Perform conversion processing on the discharge current to obtain the laser pulse signal.

[0030] In some embodiments, the comparing the laser pulse signal with a reference voltage and outputting a square wave pulse signal includes:

[0031] Perform conversion processing on the laser pulse signal to obtain a laser pulse voltage signal;

[0032] Compare the laser pulse voltage signal with the first reference voltage through the first high-speed comparator module, sample the rising edge time of the optical pulse emission circuit, and output a first stop signal;

[0033] Compare the laser pulse voltage signal with the second reference voltage through the second high-speed comparator module, sample the falling edge time of the optical pulse emission circuit, and output a second stop signal;

[0034] Integrate the rising edge time and the falling edge time of the optical pulse emission circuit, and output the square wave pulse signal.

[0035] In some embodiments, the capturing of the square wave pulse signal to obtain time interval data includes:

[0036] Calculate the time interval between the start pulse signal and the first stop signal through a first time-to-digital converter to obtain first time interval data;

[0037] Calculate the time interval between the start pulse signal and the second stop signal through a second time-to-digital converter to obtain second time interval data;

[0038] Subtract the first time interval data from the second time interval data to obtain the time interval data.

[0039] In some embodiments, the calculating based on the time interval data to obtain the laser pulse current pulse width and performing output voltage regulation processing to obtain a signal feedback amount includes:

[0040] Obtain the time interval data through the MCU module and perform calculations to obtain the laser pulse current pulse width;

[0041] According to the laser pulse current pulse width, perform output voltage regulation processing on the third resistor through the digital potentiometer module to obtain the signal feedback amount.

[0042] In some embodiments, the feedback regulation of the output voltage of the optical pulse emission circuit according to the signal feedback amount includes:

[0043] Adjust the transmission current of the optical pulse emission circuit according to the signal feedback amount to obtain the adjusted transmission current of the optical pulse emission circuit;

[0044] Adjust the charging voltage of the capacitor in the optical pulse discharge loop according to the adjusted transmission current of the optical pulse emission circuit to achieve feedback regulation of the output voltage of the optical pulse emission circuit.

[0045] The embodiments of the present application at least include the following beneficial effects: The present application provides a lidar emission circuit with pulse width compensation and its control method. This solution realizes the acquisition and regulation of the pulse width of the optical pulse current through the cooperation of a high-speed comparator module and a time-to-digital converter. The time-to-digital converter discriminates the leading edge and trailing edge times of the high-speed comparator and converts them into time signals, thereby improving the pulse width stability of the optical pulse current and overcoming the temperature drift problems of devices such as lasers and capacitors. Description of the Drawings

[0046] Figure 1 It is a schematic structural diagram of a lidar emission circuit with pulse width compensation provided by an embodiment of the present application;

[0047] Figure 2 It is a schematic step - flow diagram of a control method for a lidar emission circuit with pulse width compensation provided by an embodiment of the present application;

[0048] Figure 3 It is a schematic structural diagram of an optical pulse emission circuit provided by an embodiment of the present application;

[0049] Figure 4 It is a schematic structural diagram of an existing lidar emission circuit based on peak sampling provided by an embodiment of the present application.

[0050] Reference numerals: 1, optical pulse emission circuit; 2, pulse width sampling control signal feedback circuit; 201, first high - speed comparator module; 202, second high - speed comparator module; 203, first time - to - digital converter; 204, second time - to - digital converter; 205, MCU module; 206, digital potentiometer module; 207, third resistor. Detailed implementation manners

[0051] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the embodiments of the present application. They are only examples of systems and methods that are consistent with some aspects of the embodiments of the present application detailed in the appended claims.

[0052] It can be understood that the terms "first", "second", etc. used in the present application may be used herein to describe various concepts, but unless otherwise specified, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another. For example, without departing from the scope of the embodiments of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the words "if", "when" as used herein may be interpreted as "when...", "while...", or "in response to determining".

[0053] The terms "at least one", "a plurality", "each", "any one", etc. used in the present application, at least one includes one, two or more, a plurality includes two or more, each refers to each of the corresponding plurality, and any one refers to any one of the plurality.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used herein are for the purpose of describing the embodiments of this application only and are not intended to limit this application.

[0055] Before elaborating on the embodiments of this application in detail, some nouns and terms involved in the embodiments of this application are first explained, and the nouns and terms involved in the embodiments of this application are applicable to the following explanations.

[0056] 1) DC-DC: A DC power converter chip.

[0057] 2) FB: A common feedback pin in a DC power converter chip, which is a constant voltage value.

[0058] 3) TDC (Time Digital Convertor): A time-to-digital converter, which is a commonly used and mature technology. It usually has START and STOP pins. The main function of the chip is to calculate the signal time interval between the START pin and the STOP pin. Briefly, an external pulse signal is given to the START pin, and then the internal counter of the TDC starts to work and the timing begins. When a pulse signal arrives at the STOP pin, the TDC timing ends. The time interval value between the START signal and the STOP signal can be obtained by reading the result of the TDC timing.

[0059] 4) MCU: A microcontroller unit.

[0060] 5) GaN: A gallium nitride power switch device.

[0061] LiDAR is widely used in the fields of autonomous driving and non-contact measurement, and has broad development prospects. Accuracy is the core index of LiDAR, and high accuracy is also an important development direction of LiDAR. The accuracy of LiDAR depends on many factors. In the LiDAR circuit system, each module will affect the accuracy. Among them, the pulse width stability of the optical pulse in the emission circuit module is an important reason affecting the accuracy of LiDAR. In the related technologies, there are some deficiencies, such as Figure 4 As shown, the related technical solutions detect the peak value of the emission optical pulse current, and try to make the peak current constant by adjusting the peak current. However, even when the peak currents are the same, the pulse widths of the emission optical pulse currents are still different.

[0062] In view of this, in the embodiments of the present application, a lidar emission circuit with pulse width compensation is provided, which makes full use of the function of the TDC to realize the acquisition and adjustment of the pulse width of the optical pulse current, thereby realizing the pulse width stability of the optical pulse current, and can effectively overcome the temperature drift of devices such as lasers and capacitors. At the same time, the embodiments of the present application are more direct and accurate than the existing peak current detection and adjustment schemes. The embodiments of the present application make full use of the cooperation of the TDC and the high-speed comparator to realize the sampling and adjustment of the pulse width.

[0063] Referring to Figure 1 , Figure 1 FIG. is a structural diagram of a lidar emission circuit with pulse width compensation provided by an embodiment of the present invention. Referring to Figure 1 , the circuit includes an optical pulse emission circuit 1 and a pulse width sampling control signal feedback circuit 2. The pulse width sampling control signal feedback circuit includes a first high-speed comparator module 201, a second high-speed comparator module 202, a first time-to-digital converter 203, a second time-to-digital converter 204, an MCU module 205, a digital potentiometer module 206, and a third resistor 207. The output end of the optical pulse emission circuit is connected to the input end of the pulse width sampling control signal feedback circuit, and the output end of the pulse width sampling control signal feedback circuit is feedback-connected to the optical pulse emission circuit, where:

[0064] The optical pulse emission circuit is used to output a laser pulse signal;

[0065] Specifically, the optical pulse emission circuit includes a boost circuit and an optical pulse discharge loop. The output end of the boost circuit is connected to the input end of the optical pulse discharge loop. Among them, the boost circuit is used to obtain an input voltage signal and perform a boost process to obtain a capacitor charging voltage; the optical pulse discharge loop is used to perform an adjustment process according to the capacitor charging voltage and output a laser pulse signal.

[0066] In the embodiments of the present invention, as Figure 3 shown, the optical pulse emission circuit of the present invention is an existing mature circuit solution. Among them, C2 is the discharge capacitor of the lidar emission circuit, R2 is the sampling resistor of the optical pulse current, the non-inverting input ends of the first high-speed comparator module and the second high-speed comparator module are connected to one end of the sampling resistor R2, and the inverting input ends are the set first reference voltage V REF1 and the second reference voltage V REF2 . The first reference voltage V REF1 and the second reference voltage V REF2 can be realized by common resistor voltage division. The DC-DC chip, inductor L1, capacitor C1, diode D, resistor R4, resistor R5, etc. constitute the boost circuit V BUS , which mainly boosts the input voltage V in to the voltage V BUSR1 is a charging current-limiting resistor, D3 is a photodiode used to emit laser pulses, Q1 is a switching device, and GaN driver is a GaN gate driver. Among them, FB in the DC-DC chip is a constant reference voltage value. C2, D3, Q1, and R2 together form the discharge circuit of the optical pulse.

[0067] The pulse width sampling control signal feedback circuit is used to sample and process the laser pulse signal for pulse width calculation and judgment, and generate a signal feedback quantity.

[0068] Specifically, the positive input terminal of the first high-speed comparator module and the positive input terminal of the second high-speed comparator module are respectively connected to the output terminal of the optical pulse emission circuit. The negative input terminal of the first high-speed comparator module is connected to the first reference voltage, and the negative input terminal of the second high-speed comparator module is connected to the second reference voltage. The output terminal of the first high-speed comparator module is connected to the input terminal of the first time-to-digital converter, and the output terminal of the second high-speed comparator module is connected to the input terminal of the second time-to-digital converter. The first time-to-digital converter and the MCU module are interconnected, and the second time-to-digital converter and the MCU module are interconnected. The MCU module and the digital potentiometer module are interconnected. The output terminal of the digital potentiometer module is connected to the input terminal of the third resistor, and the output terminal of the third resistor is connected to the optical pulse emission circuit. Among them, the first high-speed comparator module is used to compare the laser pulse signal with the first reference voltage and sample the rising edge moment of the optical pulse emission circuit; the second high-speed comparator module is used to compare the laser pulse signal with the second reference voltage and sample the falling edge moment of the optical pulse emission circuit; the first time-to-digital converter is used to calculate the time interval between the start pulse signal and the first stop signal output by the first high-speed comparator module to obtain the first time interval data; the second time-to-digital converter is used to calculate the time interval between the start pulse signal and the second stop signal output by the second high-speed comparator module to obtain the second time interval data; the MCU module is used to obtain the first time interval data and the second time interval data and generate a voltage regulation signal for the digital potentiometer module; the digital potentiometer module is used to adjust the output voltage according to the voltage regulation signal of the digital potentiometer module to obtain a signal feedback quantity; the third resistor is used to transmit the signal feedback quantity to the optical pulse emission circuit.

[0069] In the embodiment of the present invention, the first high-speed comparator module belongs to the sampling module and is responsible for the rising edge moment of the sampling resistor R2 by setting a threshold; the second high-speed comparator module also belongs to the sampling module and is responsible for the falling edge moment of the sampling resistor R2 by setting a threshold; the first time-to-digital converter TDC1 is a time-to-digital conversion unit, which is used to receive the first stop signal (STOP1) output by the first high-speed comparator module to calculate the first time interval T1 between the start pulse signal START and STOP1; the second time-to-digital converter TDC2 is a time-to-digital conversion unit, which is used to receive the second stop signal (STOP2) output by the first high-speed comparator module to calculate the second time interval T2 between the start moment START and STOP2; the MCU is a calculation unit module, which is used to read the first time interval and the second time interval data of the first time-to-digital converter and the second time-to-digital converter; the digital potentiometer is a feedback signal generation module, and the MCU changes the output voltage or resistance of the digital potentiometer through I2C to generate a signal feedback amount. The third resistor R3 is a feedback signal transmission channel, and the feedback signal is transmitted to the FB pin in the DC-DC boost circuit IC through R3, thereby completing the control and change of the DC-DC boost circuit V BUS control and change.

[0070] In summary, in the embodiment of the present application, a resistor is connected in series at the discharge capacitor of the radar transmitting circuit. The high-speed comparator is used to sample the voltage on the resistor, and then compare it with the set threshold, and send the comparison result into the TDC. Since the discharge current of the optical pulse of the transmitting circuit belongs to a Gaussian waveform and is an extremely narrow pulse, the high-speed comparator can capture the leading edge and the trailing edge of the current pulse. The TDC discriminates the leading edge and trailing edge moments of the high-speed comparator and converts them into time signals. The difference between the leading edge time and the trailing edge time is the pulse width of the photocurrent. The obtained pulse width data is sent to the MCU for processing and comparison. Finally, the MCU adjusts the V BUS voltage according to the result of the current pulse width data. V BUS voltage is the charging voltage given to the discharge capacitor when the switching device is closed. When the V BUS voltage increases, the capacitor voltage increases, and the discharge pulse width increases; conversely, when the V BUS voltage decreases, the capacitor voltage decreases, and the discharge pulse width decreases.

[0071] There is a digital potentiometer between the MCU and the optical pulse transmitting circuit. The MCU controls the different output voltages of the digital potentiometer through I2C. This voltage and the feedback point FB of the optical pulse transmitting circuit together form a feedback circuit to perform feedback control on the output voltage of the optical pulse transmitting circuit.

[0072] Please refer to Figure 2, The embodiment of the present application further provides a control method for a lidar emission circuit with pulse width compensation, which can implement the above-mentioned lidar emission circuit with pulse width compensation. The method includes the following steps:

[0073] S100, Generate a start pulse signal and stimulate the optical pulse emission circuit to output a laser pulse signal according to the start pulse signal;

[0074] Specifically, generate a start pulse signal through the MCU module; the start pulse signal stimulates the optical pulse emission circuit to output a discharge current; perform conversion processing on the discharge current to obtain a laser pulse signal.

[0075] In some specific embodiments, the MCU module issues a start pulse signal START through an IO pin. The START pulse signal is connected to the GaN drive IC, so as to drive the switch device Q1 to open. At the same time, the START signal is also connected to the START pins of the first time-to-digital converter TDC1 and the second time-to-digital converter TDC2. At this time, the two TDC modules start timing. After the switch device Q1 is driven to open, the discharge capacitor C2 of the lidar emission circuit starts to discharge. The discharge current passes through the laser D3, Q1, R1 and then returns to the discharge capacitor C2 of the lidar emission circuit. At this time, the optical pulse current stimulates the laser to emit a laser pulse.

[0076] S200, Compare the laser pulse signal with a reference voltage and output a square wave pulse signal, where the square wave pulse signal includes the rising edge time and the falling edge time of the optical pulse emission circuit;

[0077] Specifically, perform conversion processing on the laser pulse signal to obtain a laser pulse voltage signal; compare the laser pulse voltage signal with a first reference voltage through the first high-speed comparator module to sample the rising edge time of the optical pulse emission circuit and output a first stop signal; compare the laser pulse voltage signal with a second reference voltage through the second high-speed comparator module to sample the falling edge time of the optical pulse emission circuit and output a second stop signal; integrate the rising edge time and the falling edge time of the optical pulse emission circuit to output a square wave pulse signal.

[0078] It should be noted that in some specific embodiments, the optical pulse current is a Gaussian waveform. This current is converted into a voltage by the resistor R2. When this voltage exceeds the set first reference voltage V REF1 and the second reference voltage V REF2 of the comparator, the output of the comparator will be inverted. At the rising edge of the optical current pulse, the outputs of the two comparators change from low to high; at the falling edge of the optical current pulse, the outputs of the two comparators change from high to low. Therefore, the output of the comparator will present a square wave pulse.

[0079] S300 captures the square-wave pulse signal to obtain time interval data;

[0080] Specifically, the first time-to-digital converter calculates the time interval between the start pulse signal and the first stop signal to obtain the first time interval data; the second time-to-digital converter calculates the time interval between the start pulse signal and the second stop signal to obtain the second time interval data; the first time interval data and the second time interval data are subtracted from each other to obtain the time interval data.

[0081] It should be noted that in some specific embodiments, the output pulses of the comparator will be captured by TDC1 and TDC2, and both TDC1 and TDC2 can be set to be triggered by the rising edge signal or the falling edge signal. Therefore, we can set TDC1 to be triggered by the rising edge and TDC2 to be triggered by the falling edge. At this time, TDC1 can capture the time interval from the START signal to the rising edge of the comparator; while TDC2 can capture the time interval from the START signal to the falling edge of the comparator. Subtracting the two time intervals can obtain the pulse width output by the comparator.

[0082] S400 calculates based on the time interval data to obtain the laser pulse current pulse width and performs output voltage adjustment processing to obtain the signal feedback amount;

[0083] Specifically, the MCU module obtains the time interval data and performs calculations to obtain the laser pulse current pulse width; according to the laser pulse current pulse width, the digital potentiometer module adjusts the output voltage of the third resistor to obtain the signal feedback amount.

[0084] It should be noted that in some specific embodiments, the MCU reads the time interval data of TDC1 and TDC2 and calculates the output pulse width of the comparator, which is the pulse width of the optical pulse current. When the measured pulse width of the optical pulse current increases, the MCU can output an I2C interface signal to the digital potentiometer to adjust the voltage value of the digital potentiometer connected to R3.

[0085] S500 performs feedback adjustment on the output voltage of the optical pulse emission circuit according to the signal feedback amount;

[0086] Specifically, the transmission current of the optical pulse emission circuit is adjusted according to the signal feedback amount to obtain the adjusted transmission current of the optical pulse emission circuit; the charging voltage of the capacitor in the optical pulse discharge loop is adjusted according to the adjusted transmission current of the optical pulse emission circuit, so as to realize the feedback adjustment of the output voltage of the optical pulse emission circuit.

[0087] It should be noted that in some specific embodiments, one end of R3 is connected to the output port of the digital potentiometer, and the other end is connected to the FB pin of the DC-DC circuit. The MCU adjusts the voltage value at the output port of the digital potentiometer through the I2C signal, so that the current of R3 changes, and then the current of R4 also changes, so that the output voltage of V BUS is adjusted. The FB pin is the feedback voltage pin of the DC-DC circuit, and its voltage remains constant, so the current of R5 remains unchanged. Briefly speaking, the resistances of R4, R5, and R3 form a current distribution network, I R5 =I R3 +I R4 . When the current of R3 changes, the current of R4 also changes. Furthermore, the output voltage V BUS also changes. When V BUS changes, the voltage of C2 also changes. Thus, when C2 discharges, the pulse width is changed. The circuit finally realizes the pulse width sampling of the optical pulse circuit. After judgment, the process of adjustment is finally carried out. The basic direction of adjustment is that if the pulse width of the collected photocurrent decreases, then increase the voltage of V BUS . If the pulse width of the collected photocurrent increases, then decrease the voltage of V BUS .

[0088] In addition, it should also be noted that another embodiment may exist in the solution of this application. For example, Figure 1 the blue dotted line in. At this time, the START pin and the STOP pin of the TDC module are short-circuited. When the rising edge of the optical pulse current arrives, the output of the comparator flips. At this time, the START pin of the TDC is triggered and starts timing. When the falling edge of the optical pulse arrives, the output of the comparator flips for the second time. At this time, the STOP pin of the TDC module is triggered. The time interval between START and STOP captured by the TDC at this time is the optical pulse data. Other logics are the same.

[0089] It can be understood that the content in the above method embodiments is applicable to this system embodiment. The functions specifically implemented in this system embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0090] The preferred embodiments of the embodiments of this application have been described above with reference to the drawings, and thus do not limit the scope of rights of the embodiments of this application. Any modifications, equivalent replacements, and improvements made by those skilled in the art without departing from the scope and essence of the embodiments of this application shall be within the scope of rights of the embodiments of this application.

Claims

1. A laser radar transmitting circuit with pulse width compensation, characterized in that: The circuit comprises an optical pulse emission circuit and a pulse width sampling control signal feedback circuit, wherein the pulse width sampling control signal feedback circuit comprises a first high-speed comparator module, a second high-speed comparator module, a first time-to-digital converter, a second time-to-digital converter, an MCU module, a digital potentiometer module and a third resistor, wherein the output end of the optical pulse emission circuit is connected to the input end of the pulse width sampling control signal feedback circuit, and the output end of the pulse width sampling control signal feedback circuit is connected to the optical pulse emission circuit for feedback, wherein: The optical pulse transmitting circuit is used to output a laser pulse signal; The optical pulse transmitting circuit comprises a boost circuit and an optical pulse discharge circuit, wherein the output end of the boost circuit is connected to the input end of the optical pulse discharge circuit, wherein: The boost circuit is used to obtain an input voltage signal and perform a boost process to obtain a capacitor charging voltage; The optical pulse discharge circuit is used to adjust and process according to the capacitor charging voltage to output the laser pulse signal; The pulse width sampling control signal feedback circuit is used to perform sampling and pulse width calculation and judgment processing on the laser pulse signal to generate a signal feedback amount; The positive input terminal of the first high-speed comparator module and the positive input terminal of the second high-speed comparator module are respectively connected to the output terminal of the optical pulse transmitting circuit, the negative input terminal of the first high-speed comparator module is connected to the first reference voltage, the negative input terminal of the second high-speed comparator module is connected to the second reference voltage, the output terminal of the first high-speed comparator module is connected to the input terminal of the first time-to-digital converter, the output terminal of the second high-speed comparator module is connected to the input terminal of the second time-to-digital converter, the first time-to-digital converter and the MCU module are connected to each other, the second time-to-digital converter and the MCU module are connected to each other, the MCU module and the digital potentiometer module are connected to each other, the output terminal of the digital potentiometer module is connected to the input terminal of the third resistor, and the output terminal of the third resistor is connected to the optical pulse transmitting circuit; The first high-speed comparator module is used to compare the laser pulse signal with the first reference voltage to sample the rising edge time of the optical pulse emission circuit; The second high-speed comparator module is used to compare the laser pulse signal with the second reference voltage to sample the falling edge time of the optical pulse emission circuit; The first time-to-digital converter is used to calculate the time interval between the start pulse signal and the first stop signal output by the first high-speed comparator module to obtain first time interval data; The second time-to-digital converter is used to calculate the time interval between the start pulse signal and the second stop signal output by the second high-speed comparator module to obtain second time interval data; The MCU module is used to obtain the first time interval data and the second time interval data, and generate a voltage adjustment signal for the digital potentiometer module; The digital potentiometer module is used to perform output voltage regulation processing according to the voltage regulation signal of the digital potentiometer module to obtain the signal feedback amount; The third resistor is used to transmit the signal feedback amount to the optical pulse transmitting circuit.

2. A control method for a laser radar transmitting circuit with pulse width compensation, characterized in that: The method comprises the following steps: Generate a start pulse signal and excite a light pulse emission circuit to output a laser pulse signal according to the start pulse signal; The laser pulse signal is compared with a reference voltage to output a square wave pulse signal, wherein the square wave pulse signal includes a rising edge time of the optical pulse transmitting circuit and a falling edge time of the optical pulse transmitting circuit, including: Converting the laser pulse signal to obtain a laser pulse voltage signal; Comparing the laser pulse voltage signal with a first reference voltage through a first high-speed comparator module, sampling the rising edge moment of the optical pulse emission circuit, and outputting a first stop signal; Comparing the laser pulse voltage signal with a second reference voltage through a second high-speed comparator module, sampling the falling edge moment of the optical pulse emission circuit, and outputting a second stop signal; Integrate the rising edge timing of the optical pulse transmitting circuit and the falling edge timing of the optical pulse transmitting circuit to output the square wave pulse signal; Capturing the square wave pulse signal to obtain time interval data includes: Calculating the time interval between the start pulse signal and the first stop signal by a first time-to-digital converter to obtain first time interval data; Calculating the time interval between the start pulse signal and the second stop signal by a second time-to-digital converter to obtain second time interval data; Subtracting the first time interval data from the second time interval data to obtain the time interval data; Calculation is performed based on the time interval data to obtain the laser pulse current pulse width and output voltage adjustment processing is performed to obtain a signal feedback amount, including: The time interval data is acquired and calculated by the MCU module to obtain the pulse width of the laser pulse current; According to the laser pulse current pulse width, the output voltage of the third resistor is adjusted by a digital potentiometer module to obtain the signal feedback amount; Feedback-regulating the output voltage of the optical pulse transmitting circuit according to the signal feedback amount includes: Adjusting the transmission current of the optical pulse transmitting circuit according to the signal feedback amount to obtain an adjusted transmission current of the optical pulse transmitting circuit; The capacitor charging voltage of the optical pulse discharge loop is adjusted according to the adjusted optical pulse emission circuit transmission current, so as to implement feedback adjustment of the output voltage of the optical pulse emission circuit.

3. The method according to claim 2, characterized in that The method of generating a start pulse signal and exciting a light pulse emission circuit to output a laser pulse signal according to the start pulse signal comprises: Generate the start pulse signal through the MCU module; The start pulse signal excites the light pulse emission circuit to output a discharge current; The discharge current is converted to obtain the laser pulse signal.

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