Laser radar transmitting circuit with pulse width compensation and control method thereof

Abstract

The invention discloses a laser radar transmitting circuit with pulse width compensation and a control method thereof. The circuit comprises an optical pulse transmitting circuit and a pulse width sampling control signal feedback circuit. The method comprises the following steps: generating a starting pulse signal and exciting an optical pulse transmitting circuit to output a laser pulse signal according to the starting pulse signal; comparing the laser pulse signal with a reference voltage, and outputting a square wave pulse signal; capturing the square wave pulse signal to obtain time interval data; carrying out calculation according to the time interval data to obtain the pulse width of the laser pulse current and carrying out output voltage regulation processing to obtain a signal feedback quantity; and performing feedback regulation on the output voltage of the optical pulse transmitting circuit according to the signal feedback quantity. According to the embodiment of the invention, pulse width acquisition and adjustment of the optical pulse current can be realized, so that the pulse width stability of the optical pulse current is improved. The laser radar transmitting circuit can be widely applied to the technical field of laser radar transmitting circuits.

Description

Technical Field

[0001] The present application relates to the technical field of laser radar transmitting circuits, and in particular to a laser radar transmitting circuit with pulse width compensation and a control method thereof. Background Art

[0002] The current laser radar transmitting circuit has the problem of unstable light pulses. Since the laser will generate heat during operation, the parasitic parameters of the laser will change at different temperatures, which causes the pulse width of the light pulse to change when the capacitor is discharged. The accuracy that the laser radar can achieve is highly dependent on the stability of the transmitting pulse width. The relevant solution is mainly to select devices with low temperature drift, such as discharge capacitors, lasers, etc., and to strengthen the stability of the power supply voltage. Despite this, the temperature drift of the current pulse width of the transmitting circuit still significantly affects the accuracy performance of the system. There are also solutions to use peak current detection to make certain adjustments, but even when the peak current is consistent, the pulse width of the transmitting light pulse current is still different.

[0003] In summary, the technical problems existing in the relevant technologies need to be improved. Summary of the invention

[0004] The main purpose of the embodiments of the present application is to propose a laser radar transmitting circuit with pulse width compensation and a control method thereof, which can realize the pulse width collection and adjustment of the light pulse current, thereby improving the pulse width stability of the light pulse current.

[0005] To achieve the above-mentioned purpose, an embodiment of the present application proposes a laser radar transmitting circuit with pulse width compensation, wherein the circuit includes a light pulse transmitting circuit and a pulse width sampling control signal feedback circuit, wherein 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, wherein the output end of the light pulse transmitting 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 light pulse transmitting circuit feedback, wherein:

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

[0007] 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.

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

[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 adjustment processing 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, 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, 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, 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 also includes:

[0013] 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;

[0014] 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;

[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 voltage adjustment signal for the digital potentiometer module;

[0018] 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;

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

[0020] To achieve the above object, another aspect of an embodiment of the present application provides a control method for a laser radar transmitting circuit with pulse width compensation, the method comprising the following steps:

[0021] Generate a start pulse signal and excite a light 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, wherein the square wave pulse signal includes a rising edge timing of the optical pulse transmitting circuit and a falling edge timing of the optical pulse transmitting circuit;

[0023] Capturing 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] The output voltage of the optical pulse transmitting circuit is feedback-regulated according to the signal feedback amount.

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

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

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

[0029] The discharge current is converted to obtain the laser pulse signal.

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

[0031] Converting the laser pulse signal to obtain a laser pulse voltage signal;

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

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

[0034] The rising edge timing of the optical pulse transmitting circuit and the falling edge timing of the optical pulse transmitting circuit are integrated to output the square wave pulse signal.

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

[0036] 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;

[0037] 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;

[0038] The first time interval data is subtracted from the second time interval data to obtain the time interval data.

[0039] In some embodiments, the calculation is performed according to the time interval data to obtain the laser pulse current pulse width and the output voltage is adjusted to obtain the signal feedback amount, including:

[0040] The time interval data is acquired and calculated by the MCU module to obtain the pulse width of the laser pulse current;

[0041] 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.

[0042] In some embodiments, the step of performing feedback adjustment on the output voltage of the optical pulse transmitting circuit according to the signal feedback amount includes:

[0043] 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;

[0044] 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.

[0045] The embodiments of the present application include at least the following beneficial effects: The present application provides a laser radar transmitting circuit with pulse width compensation and a control method thereof. The scheme cooperates with a high-speed comparator module and a time-to-digital converter. The time-to-digital converter identifies the leading and trailing edge moments of the high-speed comparator and converts them into time signals, thereby realizing pulse width acquisition and adjustment of the optical pulse current, thereby improving the pulse width stability of the optical pulse current and overcoming the temperature drift problem of devices such as lasers and capacitors. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a structural schematic diagram of a laser radar transmitting circuit with pulse width compensation provided in an embodiment of the present application;

[0047] Figure 2 It is a schematic diagram of the steps of a control method of a laser radar transmitting circuit with pulse width compensation provided in an embodiment of the present application;

[0048] Figure 3 is a schematic diagram of the structure of the optical pulse transmitting circuit provided in an embodiment of the present application;

[0049] Figure 4 It is a structural diagram of an existing peak sampling-based laser radar transmitting circuit provided in an embodiment of the present application.

[0050] Figure 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 DESCRIPTION

[0051] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. When the following description refers to the 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 consistent with some aspects of the embodiments of the present application as detailed in the attached claims.

[0052] It is understood that the terms "first", "second", etc. used in this application can be used to describe various concepts in this article, but unless otherwise specified, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another concept. For example, without departing from the scope of the embodiment 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" and "if" as used herein can be interpreted as "at the time of" or "when" or "in response to determination".

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

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

[0055] Before describing the embodiments of the present application in detail, some nouns and terms involved in the embodiments of the present application are first described. The nouns and terms involved in the embodiments of the present application are subject to the following explanations.

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

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

[0058] 3) TDC (Time Digital Convertor): Time digital converter is a commonly used mature technology. Usually there are START pin and STOP pin. The main function of the chip is to calculate the signal time interval between the START pin and the STOP pin. Simply put, the external START pin is given a pulse signal, and then the counter inside the TDC starts working and the timing begins. When the STOP pin receives a pulse signal, the TDC timing ends. The result of TDC timing can be read to know the time interval between the START signal and the STOP signal.

[0059] 4)MCU: single-chip microcomputer.

[0060] 5)GaN: Gallium nitride power switching 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 indicator 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 of the transmitting circuit module is an important factor affecting the accuracy of LiDAR. There are some deficiencies in related technologies, such as Figure 4 As shown, the related technical solution detects the peak value of the emitted light pulse current, and attempts to make the peak current constant by adjusting the peak current. However, even when the peak current is consistent, the pulse width of the emitted light pulse current is still different.

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

[0063] Reference Figure 1 , Figure 1 A structure diagram of a laser radar transmitting circuit with pulse width compensation provided by an embodiment of the present invention, referring to Figure 1 The circuit includes an optical pulse transmitting 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 transmitting 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 transmitting circuit feedback, wherein:

[0064] The optical pulse transmitting circuit is used for outputting laser pulse signals;

[0065] Specifically, the optical pulse emission circuit includes 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 perform an adjustment process according to the capacitor charging voltage and output a laser pulse signal.

[0066] In the embodiment of the present invention, Figure 3 As shown, the optical pulse transmitting circuit of the present invention is an existing mature circuit solution, wherein C2 is a discharge capacitor of the laser radar transmitting circuit, R2 is a sampling resistor of the optical pulse current, the in-phase input end 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 end is a 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 This can be achieved through common resistor voltage division. The DC-DC chip, inductor L1, capacitor C1, diode D, resistor R4, resistor R5, etc. form the boost circuit V BUS , which mainly converts the input voltage V in Increase to voltage V BUSR1 is a charging current limiting resistor, D3 is a photodiode used to emit laser pulses, Q1 is a switching device, GaN driver is a GaN gate driver, and FB in the DC-DC chip is a constant reference voltage value. C2, D3, Q1, and R2 together form the discharge circuit of the light pulse.

[0067] The pulse width sampling control signal feedback circuit is used to sample the laser pulse signal and perform pulse width calculation and judgment processing to generate a signal feedback amount.

[0068] Specifically, the positive input end of the first high-speed comparator module and the positive input end of the second high-speed comparator module are respectively connected to the output end of the optical pulse emission circuit, the negative input end of the first high-speed comparator module is connected to the first reference voltage, the negative input end of the second high-speed comparator module is connected to the second reference voltage, the output end of the first high-speed comparator module is connected to the input end of the first time digital converter, the output end of the second high-speed comparator module is connected to the input end of the second time digital converter, the first time digital converter and the MCU module are interconnected, the second time digital converter and the MCU module are interconnected, the MCU module and the digital potentiometer module are interconnected, the output end of the digital potentiometer module is connected to the input end of the third resistor, and the output end of the third resistor is connected to the optical pulse emission circuit, wherein the first high-speed comparator module is used to generate a voltage according to the laser pulse signal and the first reference voltage. The voltage is compared 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 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 to generate a voltage adjustment signal of the digital potentiometer module; the digital potentiometer module is used to perform output voltage adjustment processing according to the voltage adjustment 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 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 the 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 the threshold; the first time digital converter TDC1 is a time 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 digital converter TDC2 is a time 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 time START and STOP2; 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 digital converter and the second time 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 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, and a high-speed comparator is used to sample the voltage on the resistor, which is then compared with a set threshold value, and the comparison result is sent to the TDC. Since the discharge current of the optical pulse of the transmitting circuit belongs to a Gaussian waveform, which is an extremely narrow pulse, the high-speed comparator can capture the leading and trailing edges of the current pulse. The TDC identifies the leading and trailing edge moments of the high-speed comparator and converts them into a time signal. The difference between the leading edge moment time and the trailing edge moment 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 compares V according to the result of the current pulse width data. BUS The voltage is regulated. V BUS The voltage is the charging voltage of the discharge capacitor when the switch device is closed. BUS When the voltage increases, the capacitor voltage increases, and the discharge pulse width increases; conversely, when V BUS When the 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. The 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] See also Figure 2The embodiment of the present application also provides a control method for a laser radar transmitting circuit with pulse width compensation, which can realize the above-mentioned laser radar transmitting circuit with pulse width compensation, and the method includes the following steps:

[0073] S100, generating a start pulse signal and stimulating a light pulse emission circuit to output a laser pulse signal according to the start pulse signal;

[0074] Specifically, a start pulse signal is generated through an MCU module; the start pulse signal excites a light pulse emission circuit to output a discharge current; and the discharge current is converted to obtain a laser pulse signal.

[0075] In some specific embodiments, the MCU module sends a start pulse signal START through the IO pin. The START pulse signal is connected to the GaN driver IC, thereby driving 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 driving switch device Q1 is turned on, the discharge capacitor C2 of the laser radar transmitting circuit starts to discharge. The discharge current passes through the laser D3, Q1, and R1 and then returns to the discharge capacitor C2 of the laser radar transmitting circuit. At this time, the light pulse current excites the laser to emit a laser pulse.

[0076] S200, comparing the laser pulse signal with a reference voltage, and outputting 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;

[0077] Specifically, the laser pulse signal is converted and processed to obtain a laser pulse voltage signal; the laser pulse voltage signal is compared with the first reference voltage through a first high-speed comparator module, the rising edge moment of the optical pulse emission circuit is sampled, and a first stop signal is output; the laser pulse voltage signal is compared with the second reference voltage through a second high-speed comparator module, the falling edge moment of the optical pulse emission circuit is sampled, and a second stop signal is output; the rising edge moment of the optical pulse emission circuit and the falling edge moment of the optical pulse emission circuit are integrated to output a square wave pulse signal.

[0078] It should be noted that in some specific embodiments, the light pulse current is a Gaussian waveform, and the current is converted into a voltage by the resistor R2. When the voltage exceeds the set first reference voltage V REF1 and the second reference voltage V REF2 When the photocurrent pulse rises, the output of the two comparators changes from low to high; when the photocurrent pulse falls, the output of the two comparators changes from high to low. Therefore, the output of the comparator will present a square wave pulse.

[0079] S300, capturing a square wave pulse signal to obtain time interval data;

[0080] Specifically, the time interval between the start pulse signal and the first stop signal is calculated by a first time-to-digital converter to obtain first time interval data; the time interval between the start pulse signal and the second stop signal is calculated by a second time-to-digital converter to obtain second time interval data; the first time interval data is subtracted from the second time interval data to obtain time interval data.

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

[0082] S400, calculating according to the time interval data to obtain the laser pulse current pulse width and performing output voltage adjustment processing to obtain a signal feedback amount;

[0083] Specifically, the time interval data is acquired and calculated by the MCU module to obtain the laser pulse current pulse width; according to the laser pulse current pulse width, the output voltage of the third resistor is adjusted and processed by the digital potentiometer module 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, calculates the comparator output pulse width, and the pulse width is the pulse width of the light pulse current. When the measured pulse width of the light pulse current increases, the MCU can output an I2C interface to the digital potentiometer signal to adjust the voltage value connected to R3 by the digital potentiometer.

[0085] S500, performing feedback adjustment on the output voltage of the optical pulse transmitting circuit according to the signal feedback amount;

[0086] Specifically, the transmission current of the optical pulse transmitting circuit is adjusted according to the signal feedback amount to obtain the adjusted transmission current of the optical pulse transmitting circuit; the capacitor charging voltage of the optical pulse discharge circuit is adjusted according to the adjusted transmission current of the optical pulse transmitting circuit to realize feedback adjustment of the output voltage of the optical pulse transmitting 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 of 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 V BUS The output voltage is regulated. The FB pin is the feedback voltage pin of the DC-DC circuit, and its voltage is constant, so the current of R5 remains unchanged. Simply put, the three resistors 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. Then the output voltage V BUS will also change. BUS When the voltage of C2 changes, it will also change, so that the pulse width of C2 will be changed when it discharges. The circuit finally realizes the pulse width sampling of the optical pulse circuit, makes judgments, and then adjusts it. The basic direction of adjustment is to increase V if the collected photocurrent pulse width decreases. BUS If the collected photocurrent pulse width increases, V BUS voltage.

[0088] In addition, it should be noted that the present application scheme may also have another embodiment, such as Figure 1 The blue dotted line in the figure shows that the START pin and STOP pin of the TDC module are short-circuited. When the rising edge of the light pulse current comes, the comparator output flips, and the START pin of the TDC is triggered to start timing. When the falling edge of the light pulse comes, the comparator output flips for the second time, and the STOP pin of the TDC module is triggered. At this time, the time interval between START and STOP captured by the TDC is the light pulse data. The other logics are the same.

[0089] It can be understood that the contents of the above method embodiments are all applicable to the present system embodiments, the functions specifically implemented by the present system embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0090] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but the scope of the rights of the present invention is not limited thereto. Any modification, equivalent substitution and improvement made by a person skilled in the art without departing from the scope and essence of the present invention should be within the scope of the rights of the present invention.

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 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.

2. The circuit according to claim 1, characterized in that 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 perform adjustment processing according to the capacitor charging voltage and output the laser pulse signal.

3. The circuit according to claim 1, characterized in that 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.

4. The circuit according to claim 1, characterized in that Also includes: 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.

5. 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; Compare the laser pulse signal with a reference voltage and output a square wave pulse signal, wherein the square wave pulse signal includes a rising edge timing of the optical pulse transmitting circuit and a falling edge timing of the optical pulse transmitting circuit; Capturing the square wave pulse signal to obtain time interval data; 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; The output voltage of the optical pulse transmitting circuit is feedback-regulated according to the signal feedback amount.

6. The method according to claim 5, 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.

7. The method according to claim 5, characterized in that The step of comparing the laser pulse signal with a reference voltage and outputting a square wave pulse signal comprises: Converting the laser pulse signal to obtain a laser pulse voltage signal; Comparing the laser pulse voltage signal with the first reference voltage through a first high-speed comparator module, sampling the rising edge time of the optical pulse emission circuit, and outputting a first stop signal; Comparing the laser pulse voltage signal with the second reference voltage through a second high-speed comparator module, sampling the falling edge time of the optical pulse emission circuit, and outputting a second stop signal; The rising edge timing of the optical pulse transmitting circuit and the falling edge timing of the optical pulse transmitting circuit are integrated to output the square wave pulse signal.

8. The method according to claim 5, characterized in that The step of 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; The first time interval data is subtracted from the second time interval data to obtain the time interval data.

9. The method according to claim 5, characterized in that The step of calculating according to the time interval data to obtain the laser pulse current pulse width and performing output voltage adjustment processing to obtain a signal feedback amount includes: 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.

10. The method according to claim 5, characterized in that The step of performing feedback adjustment on the output voltage of the optical pulse transmitting circuit according to the signal feedback amount comprises: 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.

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