Laser distance measuring sensor circuit

Abstract

The invention provides a laser ranging sensor circuit. Comprising a microcontroller, a laser tube high-speed driving module connected with the microcontroller, a transmitting pulse triggering module connected with the laser tube high-speed driving module, a TDC module connected with the transmitting pulse triggering module, and an optical signal amplification and comparison module connected with the TDC module. The laser receiving module is connected with the optical signal amplification and comparison module; the APD high-voltage bias and voltage regulation module is connected with the laser receiving module; the invention has the following beneficial effects: through the design of the resistance-capacitance device and the Schmidt input phase inverter, no auxiliary optical system is provided, the size is small, and the circuit is reliable; the APD high-voltage bias and voltage regulation circuit has the functions of real-time current detection, voltage detection, voltage regulation and the like; and one optical pulse signal is detected twice at the same time, so that the redundancy is increased, and the detection precision can also be improved.

Description

Technical Field

[0001] This invention relates to the field of ranging sensor technology, and in particular to a laser ranging sensor circuit. Background Technology

[0002] With the development of industrial automation, laser rangefinders are being used more and more, and the detection distance is getting longer and longer. To accurately and quickly detect objects, the requirements for the detection accuracy and speed of laser rangefinders are becoming increasingly stringent. At the same time, with increasing integration, there is a need for smaller laser rangefinders. However, existing technologies have the following drawbacks:

[0003] 1. Typically, two receiver tubes are used. One receiver tube is close to the laser tube to trigger the pulse transmission circuit, and the other is used for distance detection. The optical design is complex, the size is large, and the overall cost is high.

[0004] 2. The TDC module has only one TDC circuit to detect START and STOP signals. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a laser ranging sensor circuit to solve the problems of complex optical design, large size, high overall cost, and the fact that the TDC module only has one TDC circuit to detect START and STOP signals in the existing laser ranging sensors.

[0006] To achieve the above and other related objectives, the present invention provides the following technical solution:

[0007] A laser ranging sensor circuit includes a microcontroller, a high-speed laser tube driving module connected to the microcontroller, a transmission pulse triggering module connected to the high-speed laser tube driving module, a TDC module connected to the transmission pulse triggering module, an optical signal amplification and comparison module connected to the TDC module, a laser receiving module connected to the optical signal amplification and comparison module, and an APD high-voltage bias and voltage regulation module connected to the laser receiving module. The microcontroller is also connected to the TDC module, the optical signal amplification and comparison module, and the APD high-voltage bias and voltage regulation module, respectively.

[0008] The TDC module is equipped with START1 port, START2 port, STOP1 port and STOP2 port. The output of the transmit pulse trigger module is connected to START1 port and START2 port respectively. The STOP1 port and STOP2 port are connected to the output of the optical signal amplification and comparison module respectively.

[0009] In one embodiment of the present invention, the high-speed laser tube driving module includes a laser tube driving chip, a laser tube, and other circuit components. One of the control terminals of the laser tube driving chip is connected to the microcontroller, and two of the control terminals of the laser tube driving chip are respectively connected to the positive and negative terminals of the laser tube. The negative terminal of the laser tube is also connected to the emission pulse triggering module.

[0010] In one embodiment of the present invention, the transmit pulse triggering module includes a pulse triggering chip, a third resistor, a third capacitor, and other circuit components. The pulse triggering chip has an inverter inside. One of the control terminals of the pulse triggering chip is connected to one end of the third capacitor through the third resistor. The other end of the third capacitor is connected to the high-speed drive module of the laser tube. One of the control terminals of the pulse triggering chip is connected to the START1 port and the START2 port respectively.

[0011] In one embodiment of the present invention, the optical signal amplification and comparison module includes a transimpedance amplifier, a variable gain amplifier, and a comparator. The input terminal of the transimpedance amplifier is connected to the laser receiving module, the output terminal of the transimpedance amplifier is connected to the input terminal of the variable gain amplifier, the output terminal of the variable gain amplifier is connected to the non-inverting input terminal of the comparator, the inverting input terminal of the comparator is connected to the microcontroller, and the output terminal of the comparator is connected to the STOP1 port and the STOP2 port, respectively.

[0012] In one embodiment of the present invention, the laser receiving module includes a receiving tube, a ninth resistor, and a fourteenth resistor. The positive terminal of the receiving tube is connected to the optical signal amplification and comparison module. The positive terminal of the receiving tube is also connected to the APD high voltage bias and voltage regulation module through the fourteenth resistor. The negative terminal of the receiving tube is also connected to the APD high voltage bias and voltage regulation module through the ninth resistor.

[0013] In one embodiment of the present invention, the APD high-voltage bias and voltage regulation module includes a voltage control chip, a Boost submodule, a current and voltage detection submodule, a voltage regulation submodule, and other circuit components. The voltage control chip contains an error amplifier. The Boost submodule includes a field-effect transistor, a second inductor, a diode, and the voltage control chip. One control terminal of the voltage control chip is connected to the gate of the field-effect transistor. The drain of the field-effect transistor is connected to one end of the second inductor and the anode of the diode, respectively. The source of the field-effect transistor is connected to the voltage control chip and grounded.

[0014] In one embodiment of the present invention, the current detection submodule includes a fifth resistor and a voltage control chip, two control terminals of the voltage control chip being connected to both ends of the fifth resistor; the voltage detection submodule includes an eighth resistor, a thirteenth resistor and a microcontroller, one end of the eighth resistor being connected to the voltage control chip, the other end of the eighth resistor being connected to the ADC1 port of the microcontroller and one end of the thirteenth resistor respectively, and the other end of the thirteenth resistor being connected to the voltage control chip and grounded.

[0015] In one embodiment of the present invention, the voltage regulation submodule includes a voltage follower, a tenth resistor, a transistor, a twelfth resistor, and a microcontroller. The non-inverting input of the voltage follower is connected to the DAC1 port of the microcontroller. The inverting input of the voltage follower is connected to the voltage control chip and grounded through the twelfth resistor. The output of the voltage follower is connected to the base of the transistor through the tenth resistor. The emitter of the transistor is also connected to the voltage control chip and grounded through the twelfth resistor.

[0016] In one embodiment of the present invention, a temperature detection module connected to the microcontroller is further included. The temperature detection module includes a fourth resistor, a thermistor, and a fourth capacitor. One end of the fourth resistor is connected to a voltage source, and the other end of the fourth resistor is connected to one end of the thermistor and the microcontroller, respectively. The other end of the thermistor is grounded, and the thermistor and the fourth capacitor are connected in parallel.

[0017] As described above, the laser ranging sensor circuit of the present invention has the following beneficial effects:

[0018] 1. The APD high-voltage bias and voltage regulation circuit in this invention has functions such as real-time current detection, voltage detection, and voltage adjustment to prevent overcurrent damage to the APD after the avalanche effect. At the same time, the microcontroller detects the temperature and adjusts the bias voltage of the APD to keep it operating in the optimal range. In particular, it reduces the bias voltage of the APD in high-temperature environments to avoid high-temperature damage. In extreme cases, the bias voltage of the laser tube LD and the APD can be turned off to avoid high-temperature damage.

[0019] 2. This invention converts the LD trigger signal of the laser tube into the START signal of the TDC through the design of resistive capacitor components and Schmitt input inverter. The circuit is reliable, cost-effective, requires no auxiliary optical system, and is small in size.

[0020] 3. The TDC module in this invention has two independent TDC circuits. The START pulse signal triggers START1 and START2 simultaneously. The amplified and compared received signals are connected to STOP1 and STOP2 simultaneously. One optical pulse signal is used to measure the time and pulse width twice at the same time, which increases redundancy and can improve detection accuracy. In addition, the flight time can be compensated by calculating the time of the STOP pulse, which improves the consistency of distance to different objects. Attached Figure Description

[0021] Figure 1 The diagram shown is an overall structural block diagram of the laser ranging sensor circuit disclosed in the embodiments of the present invention;

[0022] Figure 2 The diagram shown is a schematic of the laser ranging sensor circuit disclosed in an embodiment of the present invention.

[0023] Figure 3 This is a schematic diagram showing the calculation of the STOP pulse time in the laser ranging sensor circuit disclosed in this embodiment of the invention;

[0024] Figure 4 The diagram shown is a schematic of the signal curve at the positive terminal of comparator COM1 in the laser ranging sensor circuit disclosed in this embodiment of the invention. Detailed Implementation

[0025] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. It should be noted that, unless otherwise specified, the following embodiments and features described herein can be combined with each other.

[0026] Please see Figure 1 and Figure 2 The present invention provides a laser ranging sensor circuit, including: a microcontroller, a high-speed laser tube driving module, a pulse emission triggering module, a TDC module, an optical signal amplification and comparison module, a laser receiving module, an APD high-voltage bias and voltage regulation module, and a temperature detection module; wherein, the TDC module is provided with a START1 port, a START2 port, a STOP1 port, and a STOP2 port.

[0027] Please see Figure 2 The high-speed laser tube drive module includes a laser tube driver chip, a laser tube, and other circuit components. The following explanation uses the laser tube driver chip U1 and the laser tube LD as examples. The second pin (INP port) of the laser tube driver chip U1 is connected to the TRIG port of the microcontroller. The fourth pin (P port) and the fifth pin (N port) of the laser tube driver chip U1 are connected to the positive and negative terminals of the laser tube LD. The negative terminal of the laser tube LD is also connected to the emission pulse trigger module.

[0028] Please see Figure 2 The pulse triggering module includes a pulse triggering chip, a third resistor, a third capacitor, and other circuit components. The following description uses the pulse triggering chip U2, the third resistor R3, and the third capacitor C3 as examples. The pulse triggering chip U2 has an inverter inside. The second pin of the pulse triggering chip U2 is connected to one end of the third capacitor C3 through the third resistor R3. The other end of the third capacitor C3 is connected to the high-speed drive module of the laser tube. The fourth pin of the pulse triggering chip U2 is connected to the START1 port and the START2 port, respectively.

[0029] Please see Figure 2 The optical signal amplification and comparison module includes a transimpedance amplifier, a variable gain amplifier, and a comparator. The following explanation uses the transimpedance amplifier TIA, the variable gain amplifier VGA, and the comparator COM1 as examples. The input terminal of the transimpedance amplifier TIA is connected to the laser receiving module, the output terminal of the transimpedance amplifier TIA is connected to the input terminal of the variable gain amplifier VGA, the output terminal of the variable gain amplifier VGA is connected to the non-inverting input terminal of the comparator COM1, the inverting input terminal of the comparator COM1 is connected to the DAC0 port of the microcontroller, and the output terminal of the comparator COM1 is connected to the STOP1 port and the STOP2 port, respectively.

[0030] It should be noted that the signal amplification and comparison module consists of TIA, VGA and COM1, where the microcontroller's DAC0 is connected to the negative phase input of comparator COM1. When the ambient light is strong, such as sunlight, the noise signal generated may cause comparator COM1 to be falsely triggered. In this case, the value of DAC0 is increased to avoid false triggering. Although the detection distance decreases, it is still more reliable than false triggering.

[0031] Please see Figure 2 The laser receiving module includes a receiving tube, a ninth resistor, and a fourteenth resistor. The following explanation uses the receiving tube APD, the ninth resistor R9, and the fourteenth resistor R14 as an example. The positive terminal of the receiving tube APD is connected to the optical signal amplification and comparison module. The positive terminal of the receiving tube APD is also connected to the APD high voltage bias and voltage regulation module through the fourteenth resistor R14. The negative terminal of the receiving tube APD is also connected to the APD high voltage bias and voltage regulation module through the ninth resistor R9.

[0032] Please see Figure 1 The APD high-voltage bias and voltage regulation module includes a voltage control chip, a Boost submodule, a current and voltage detection submodule, a voltage regulation submodule, and other circuit components.

[0033] Please see Figure 2The Boost converter module includes a field-effect transistor (FET), a second inductor, a diode, and a voltage control chip. The following explanation uses the FET Q1, the second inductor L2, the diode D2, and the voltage control chip U3 as an example. The voltage control chip U3 contains an error amplifier. The SW port of the voltage control chip U3 is connected to the gate of the FET Q1. The drain of the FET Q1 is connected to one end of the second inductor L2 and the anode of the diode D2, respectively. The source of the FET Q1 is connected to the voltage control chip U3 and grounded.

[0034] The current detection submodule includes a fifth resistor and a voltage control chip. The following explanation uses the fifth resistor R5 and voltage control chip U3 as an example. The S+ and S- ports of the voltage control chip U3 are connected to both ends of the fifth resistor R5. It should be noted that the voltage control chip U3 and the fifth resistor R5 form a current monitoring system. The fifth resistor R5 is a current sampling resistor; the current Ia passing through the fifth resistor R5 generates a voltage drop. The S+ and S- ports of the voltage control chip U3 monitor the voltage across the fifth resistor R5, achieving I / V conversion and enabling current value detection. Typically, the resistance of the fifth resistor R5 is small, and the resulting voltage drop is negligible compared to the voltage values ​​V1 and V2. When the voltage between the S+ and S- ports of the voltage control chip U3 exceeds the design value, the voltage control chip U3 reduces the conduction time of the field-effect transistor Q1, lowering the V1 voltage to prevent continuous overcurrent in the APD circuit, which could lead to overheating and damage to the APD.

[0035] The voltage detection submodule includes an eighth resistor, a thirteenth resistor, and a microcontroller. The eighth resistor R8 and the thirteenth resistor R13 are selected as examples for the following explanation. One end of the eighth resistor R8 is connected to the voltage control chip U3. The other end of the eighth resistor R8 is connected to the ADC1 port of the microcontroller and one end of the thirteenth resistor R13. The other end of the thirteenth resistor R13 is connected to the voltage control chip U3 and grounded.

[0036] It should be noted that the voltage divider formed by the eighth resistor R8 and the thirteenth resistor R13 is connected to the ADC1 port of the microcontroller. The ADC1 detects the APD bias voltage V2. Based on the temperature characteristics of the APD, the DAC1 adjusts the APD bias voltage, especially under high-temperature conditions, to reduce the APD bias voltage and prevent APD burnout. Under extreme high-temperature conditions, the microcontroller's IO1 pin outputs a low level, and the voltage control chip U3 stops working. At this time, the voltage of V2 is 5V minus the voltage drop of diode D2, which is much lower than the normal operating voltage. Simultaneously, the microcontroller's TRIG port outputs a low level, the laser tube driver chip U1 stops working, the laser tube LD is cut off, and no current flows, ensuring that the temperature-sensitive device is not damaged under extreme high-temperature conditions.

[0037] The voltage regulation submodule includes a voltage follower, a tenth resistor, a transistor, a twelfth resistor, and a microcontroller. The following explanation uses the voltage follower OP1, the tenth resistor R10, the transistor Q2, and the twelfth resistor R12 as an example. The non-inverting input of the voltage follower OP1 is connected to the DAC1 port of the microcontroller. The inverting input of the voltage follower OP1 is connected to the voltage control chip U3 and grounded through the twelfth resistor R12. The output of the voltage follower OP1 is connected to the base of the transistor Q2 through the tenth resistor R10. The emitter of the transistor Q2 is also connected to the voltage control chip U3 and grounded through the twelfth resistor R12.

[0038] It should be noted that DAC1 in the microcontroller is connected to OP1. OP1 acts as a voltage follower, providing high input impedance and low output impedance. The negative input of the voltage follower OP1 is connected to the twelfth resistor R12, and the output of the voltage follower OP1 is connected to the tenth resistor R10, driving transistor Q2. When the resistance of the twelfth resistor R12 is fixed, its current is determined by the output voltage of DAC1. When the output voltage of DAC1 is 0V, transistor Q2 is cut off, no current flows through the collector-emitter junction of transistor Q2, and the voltage at point B is... ,Right now As the voltage of DAC1 gradually increases, transistor Q2 changes from the cutoff state to the amplification state until it becomes saturated. If the voltage drop across the collector and emitter of transistor Q2 is ignored, when transistor Q2 is saturated, According to the formula, when current flows through the collector-emitter junction of transistor Q2, the impedance between point B and GND decreases, the Ib current increases, and overall, the V2 voltage increases. The larger the current through the collector-emitter junction of transistor Q2, the higher the V2 voltage; conversely, the smaller the current through the collector-emitter junction of transistor Q2, the lower the V2 voltage. The collector-emitter current of transistor Q2 is also controlled by the voltage of DAC1. Under normal operation, the output voltage of DAC1 is relatively high, ensuring that transistor Q2 is in amplification mode, or even saturation mode. As the operating temperature continues to rise and exceeds the system's set temperature value, the output voltage of DAC1 decreases, and the V2 voltage value decreases.

[0039] It should also be noted that the fifth resistor R5 in the APD high-voltage bias and voltage regulation module is in the main circuit, and the maximum current that the APD can pass can be adjusted by setting the resistance value of the fifth resistor R5; the sixth resistor R6 is a dummy load, which is beneficial to the stability of the APD bias voltage; the ninth resistor R9 and the thirteenth resistor R13 can limit the current of the APD device to ensure that the APD will not be damaged.

[0040] In the APD high-voltage bias and voltage regulation module, the seventh resistor R7 and the eleventh resistor R11 are connected between V2 and GND, and the sixth capacitor C6 is connected in parallel with the seventh resistor R7 to reduce the high-frequency signal impedance and increase the transient response of point FB to the V2 voltage. When V2 is in steady state, the impedance of the sixth capacitor C6 is infinite, and the influence of the impedance of the sixth capacitor C6 can be ignored. When the V2 voltage increases, the current through the eleventh resistor R11 and the seventh resistor R7 increases; when the V2 voltage decreases, the current through the eleventh resistor R11 and the seventh resistor R7 decreases. The voltage control chip U3 has a built-in error amplifier, and the voltage of the FB pin of the voltage control chip U3 is determined by the ref voltage, that is, the voltage of point B is the ref voltage. In the internal logic processing of the voltage control chip U3, the S+ and S- voltage processing has a higher priority than the FB voltage processing, that is, the V2 voltage is reduced when the current Ia is overcurrent, and the voltage value of V2 is maintained when there is no overcurrent.

[0041] Please see Figure 2 The temperature detection module includes a fourth resistor, a thermistor, and a fourth capacitor. The following explanation uses the fourth resistor R4, the thermistor NTC1, and the fourth capacitor C4 as an example. One end of the fourth resistor R4 is connected to the 5V voltage source. The other end of the fourth resistor R4 is connected to one end of the thermistor NTC1 and the ADC0 port of the microcontroller. The other end of the thermistor NTC1 is grounded, and the thermistor NTC1 is connected in parallel with the fourth capacitor C4.

[0042] It should be noted that the fourth resistor R4 and the thermistor NTC1 are connected to the microcontroller's ADC0 after voltage division. NTC1 is a negative temperature series thermistor; the higher the temperature, the lower the resistance, and the lower the temperature, the higher the resistance. When the temperature rises, the resistance of the thermistor NTC1 decreases, the voltage at point C decreases, and the temperature is converted into a voltage quantity. The voltage sampled by the microcontroller's ADC0 port realizes temperature acquisition. Through the resistance and temperature characteristics of the thermistor NTC1, the actual temperature value can be calculated. In PCB design, the thermistor NTC1 should be placed close to the APD. Temperature compensation can also be performed on the sensor distance value to reduce the impact of temperature on the sensor distance accuracy.

[0043] Furthermore, the laser ranging sensor in this invention operates on the principle of Time-of-Flight (TOF), calculating the time difference in laser flight between the sensor and the object being measured. ,in, For distance, For the speed of light, The time of flight is specified; the laser tube driver chip U1 is driven by the TRIG port of the microcontroller, and the laser tube driver chip U1 controls the conduction and cutoff of the laser tube LD. When the laser tube LD is turned on, Figure 2Midpoint A experiences a drop in voltage, generating a falling edge pulse signal. This pulse signal passes through the third capacitor C3 and the third resistor R3, and is captured by the inverter in the pulse trigger chip U2, generating a START pulse signal. This START pulse signal is connected to the START1 and START2 ports on the TDC module, effectively driving both START1 and START2 simultaneously. The signal received by the receiving transistor APD is amplified and compared, then simultaneously connected to STOP1 and STOP2 in the TDC module. Timing begins with the rising edge of the START pulse. Upon receiving the STOP pulse, the rising and falling edge times of the STOP pulse signal are recorded. The TDC module calculates the time of the START1 and STOP1 pulse signals cycle by cycle, such as t1 being the flight time and t3 being the STOP pulse width, and the time of the START2 and STOP2 pulse signals, such as t4 being the flight time and t6 being the STOP pulse width. Therefore, a single STOP pulse signal is tested twice, which helps improve the sensor's ranging accuracy. For details, please refer to [link to relevant documentation]. Figure 3 ;

[0044] Within the measurement range, once the object distance is determined, higher reflectivity results in larger values ​​for t3 and t6; conversely, lower reflectivity results in smaller values ​​for t3 and t6. At the positive input of comparator COM1, a stronger signal rises faster, while a weaker signal rises slower, causing a timing deviation in the comparator's triggering and thus affecting the inconsistent rising edge of the STOP pulse signal. Therefore, based on the values ​​of t3 and t6, compensation can be made to adjust the rising edge of the STOP pulse signal, resolving the distance deviation caused by objects with different reflectivities and improving the consistency of distance measurement for different reflective objects. For details, please refer to [link to relevant documentation]. Figure 4 .

[0045] Furthermore, there are other alternative solutions that can achieve the same purpose as the invention, in response to the above technical solutions: 1. Using a similar architecture, only changing the inverter with or without a Schmitt trigger; 2. Using a similar architecture, changing the communication method between the microcontroller and the TDC module to another method; 3. Using a similar architecture, changing the laser module to another small spot light source, such as a VCSEL light source; 4. Using a similar design, not for ranging, but for switching products.

[0046] In summary: 1. This invention utilizes a resistive capacitor and Schmitt input inverter design, resulting in an auxiliary optical system that is small in size and reliable in circuitry; 2. The APD high-voltage bias and voltage regulation circuit in this invention has functions such as real-time current detection, voltage detection, and voltage adjustment. Simultaneously, the microcontroller detects temperature and adjusts the APD bias voltage to ensure the APD operates within its optimal range, especially in high-temperature environments, reducing the APD bias voltage to prevent burnout; 3. This invention measures a single optical pulse signal twice simultaneously, increasing redundancy and improving detection accuracy; 4. Based on the inconsistency in reflectivity, this invention calculates the pulse width and performs time-of-flight compensation, thereby improving the consistency of distances to different reflecting objects.

[0047] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. All equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this invention should still be covered by the claims of this invention.

Claims

1. A laser ranging sensor circuit, characterized by: The application relates to a laser ranging system, which comprises a microcontroller, a laser tube high-speed driving module connected with the microcontroller, a transmitting pulse trigger module connected with the laser tube high-speed driving module, a TDC module connected with the transmitting pulse trigger module, an optical signal amplification and comparison module connected with the TDC module, a laser receiving module connected with the optical signal amplification and comparison module and an APD high-voltage bias and voltage regulating module connected with the laser receiving module, wherein the microcontroller is also connected with the TDC module, the optical signal amplification and comparison module and the APD high-voltage bias and voltage regulating module respectively. The TDC module is provided with a START1 port, a START2 port, a STOP1 port and a STOP2 port, the output end of the transmitting pulse trigger module is connected with the START1 port and the START2 port respectively, and the STOP1 port and the STOP2 port are connected with the output end of the optical signal amplification and comparison module respectively.

2. A laser range sensor circuit according to claim 1, characterized in that: The laser tube high-speed driving module comprises a laser tube driving chip, a laser tube and other circuit components, one control end of the laser tube driving chip is connected with the microcontroller, two control ends of the laser tube driving chip are connected with the positive and negative electrodes of the laser tube respectively, and the negative electrode of the laser tube is also connected with the transmitting pulse trigger module.

3. A laser range sensor circuit according to claim 1, wherein: The transmitting pulse trigger module comprises a pulse trigger chip, a third resistor, a third capacitor and other circuit components, an inverter is arranged in the pulse trigger chip, one control end of the pulse trigger chip is connected with one end of the third capacitor through the third resistor, the other end of the third capacitor is connected with the laser tube high-speed driving module, and one control end of the pulse trigger chip is connected with the START1 port and the START2 port respectively.

4. A laser range sensor circuit according to claim 1, wherein: The optical signal amplification and comparison module comprises a transimpedance amplifier, a variable gain amplifier and a comparator, the input end of the transimpedance amplifier is connected with the laser receiving module, the output end of the transimpedance amplifier is connected with the input end of the variable gain amplifier, the output end of the variable gain amplifier is connected with the non-inverting input end of the comparator, the inverting input end of the comparator is connected with the microcontroller, and the output end of the comparator is connected with the STOP1 port and the STOP2 port respectively.

5. A laser range sensor circuit according to claim 1, wherein: The laser receiving module comprises a receiving tube, a ninth resistor and a fourteenth resistor, the positive electrode of the receiving tube is connected with the optical signal amplification and comparison module, the positive electrode of the receiving tube is also connected with the APD high-voltage bias and voltage regulating module through the fourteenth resistor, and the negative electrode of the receiving tube is also connected with the APD high-voltage bias and voltage regulating module through the ninth resistor.

6. A laser range sensor circuit according to claim 1, wherein: The APD high-voltage biasing and voltage regulating module comprises a voltage control chip, a Boost voltage boosting submodule, a current and voltage detection submodule, a voltage regulating submodule and other circuit components, the voltage control chip is provided with an error amplifier, wherein the Boost voltage boosting submodule comprises a field effect transistor, a second inductor, a diode and a voltage control chip, one control end of the voltage control chip is connected with the gate of the field effect transistor, the drain of the field effect transistor is connected with one end of the second inductor and the anode of the diode respectively, and the source of the field effect transistor is connected with the voltage control chip and grounded.

7. A laser range sensor circuit according to claim 6, wherein: The current detection submodule comprises a fifth resistor and a voltage control chip, two control ends of the voltage control chip are connected with two ends of the fifth resistor; the voltage detection submodule comprises an eighth resistor, a thirteenth resistor and a microcontroller, one end of the eighth resistor is connected with the voltage control chip, the other end of the eighth resistor is connected with the ADC1 port of the microcontroller and one end of the thirteenth resistor respectively, and the other end of the thirteenth resistor is connected with the voltage control chip and grounded.

8. A laser range sensor circuit according to claim 6, wherein: The voltage regulating submodule comprises a voltage follower, a tenth resistor, a triode, a twelfth resistor and a microcontroller, the non-inverting input end of the voltage follower is connected with the DAC1 port of the microcontroller, the inverting input end of the voltage follower is connected with the voltage control chip through the twelfth resistor and grounded, the output end of the voltage follower is connected with the base of the triode through the tenth resistor, and the emitter of the triode is also connected with the voltage control chip through the twelfth resistor and grounded.

9. A laser range sensor circuit according to claim 1, wherein: Further comprising a temperature detection module connected with the microcontroller, the temperature detection module comprises a fourth resistor, a thermistor and a fourth capacitor, one end of the fourth resistor is connected with a voltage source, the other end of the fourth resistor is connected with the thermistor and the microcontroller respectively, the other end of the thermistor is grounded, and the thermistor is connected with the fourth capacitor in parallel.

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