CN210864034U - Light receiving module and laser radar - Google Patents
Light receiving module and laser radar Download PDFInfo
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- CN210864034U CN210864034U CN201921501182.5U CN201921501182U CN210864034U CN 210864034 U CN210864034 U CN 210864034U CN 201921501182 U CN201921501182 U CN 201921501182U CN 210864034 U CN210864034 U CN 210864034U
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Abstract
The utility model discloses a light receiving module and laser radar. The light receiving module comprises a photodiode, a current sampling module and a voltage regulating module; the current sampling module is used for collecting the current of a loop where the photodiode is located and generating a corresponding sampling electric signal; the voltage regulating module is respectively connected with the current sampling module and used for regulating the voltage at two ends of the photodiode within a working voltage range according to the change of the sampling electric signal. The utility model provides a light receiving module and laser radar can guarantee that photodiode maintains the optimal operating voltage scope all the time.
Description
Technical Field
The embodiment of the utility model provides a relate to electronic circuit technical field, especially relate to a light receiving module and laser radar.
Background
Photodiodes, such as Avalanche Photodiodes (APDs), are photosensitive elements often used in laser communication, and can well meet the requirements of detection and reception of optical signals. APDs require high values of reverse bias voltage under optimal operating conditions and are very sensitive to the accuracy and stability of the reverse bias voltage, and deviations from the optimal operating voltage range can degrade APD performance or irreversibly damage it. Therefore, applying a stable, precise and controlled reverse bias voltage to the APD is critical to the proper operation of the APD.
In the prior art, a temperature sensor is usually arranged to compensate the influence of temperature on the leakage current of the APD, the influence of illumination on the leakage current of the APD is ignored, and when the illumination is changed, the APD still deviates from the optimal working voltage range, so that the working performance of the APD is influenced.
SUMMERY OF THE UTILITY MODEL
The utility model provides a light receiving module and laser radar to guarantee that photodiode maintains throughout at the optimal operating voltage scope.
In a first aspect, an embodiment of the present invention provides a light receiving module, including a photodiode, a current sampling module, and a voltage regulating module; the current sampling module is used for collecting the current of a loop where the photodiode is located and generating a corresponding sampling electric signal; the voltage regulating module is respectively connected with the current sampling module and used for regulating the voltages at two ends of the photodiode within a working voltage range according to the change of the sampling electric signal.
Optionally, the current sampling module includes a sampling current collecting end and a sampling voltage output end, and the voltage regulating module includes a sampling voltage receiving end and a voltage regulating signal output end; the sampling current acquisition end comprises a sampling current first acquisition end and a sampling current second acquisition end;
the current sampling module comprises a sampling resistor and an amplifier, the sampling resistor comprises a first sampling current collecting end and a second sampling current collecting end, and the first sampling current collecting end of the sampling resistor is connected with the voltage regulating signal output end; a second sampling end of the sampling current of the sampling resistor is connected with the cathode of the photodiode; the sampling resistor is connected in series with a loop where the photodiode is located; the amplifier comprises a first sampling current receiving end, a second sampling current receiving end and the sampling voltage output end; the sampling voltage output end is electrically connected with the sampling voltage receiving end;
the first sampling current receiving end is electrically connected with the first sampling current collecting end, and the second sampling current receiving end is electrically connected with the second sampling current collecting end.
Optionally, the current sampling module further includes:
the circuit comprises a first resistor, a second resistor, a third resistor and a fourth resistor;
the first end of the first resistor is electrically connected with the first sampling end of the sampling current of the sampling resistor, the second end of the first resistor is respectively and electrically connected with the first end of the third resistor and the first receiving end of the sampling current of the amplifier, and the second end of the third resistor is grounded;
the first end of the second resistor is electrically connected with the second sampling end of the sampling current of the sampling resistor, the second end of the second resistor is respectively electrically connected with the first end of the fourth resistor and the second receiving end of the sampling current of the amplifier, and the second end of the fourth resistor is grounded.
Optionally, the resistance value of the first resistor is R1, the resistance value of the second resistor is R2, the resistance value of the third resistor is R3, and the resistance value of the fourth resistor is R4;
wherein, R1/R3 ═ R2/R4.
Optionally, the light receiving module further includes:
a current limiting resistor and a power supply;
the voltage regulating module also comprises a voltage signal input end;
the anode of the photodiode is electrically connected with the cathode of the power supply, and the second end of the current limiting resistor is electrically connected with the sampling current acquisition end of the current sampling module;
and the positive pole of the power supply is electrically connected with the voltage signal input end of the voltage regulating module.
Optionally, the resistance value of the sampling resistor is R5, and the resistance value of the current limiting resistor is R6, wherein R1/R5 is greater than or equal to 10, and R2/R5 is greater than or equal to 10; r6 > R5.
Optionally, the light receiving module further includes: a capacitor;
the first end of the capacitor is respectively connected with the first end of the current-limiting resistor and the cathode of the photodiode, and the second end of the capacitor is used as the output end of the light receiving module.
Optionally, the voltage regulating module is configured to regulate the voltage across the photodiode within a working voltage range when the variation of the sampled electrical signal is greater than a first preset value.
Optionally, the photodiode is an avalanche photodiode, a single photon avalanche diode, or a PIN photodiode.
In a second aspect, an embodiment of the present invention further provides a laser radar, including a light emitting module, and further including any one of the light receiving modules described in the first aspect; the light emitting module is used for generating laser beams and scanning the scanning area; the light receiving module is used for receiving a reflected light beam formed by reflecting the laser beam by an object in a scanning area.
The embodiment of the utility model provides a light receiving module and laser radar gathers the electric current in photodiode place return circuit and generates corresponding sampling signal of telecommunication through current sampling module, and the voltage at photodiode both ends is adjusted in real time to the sampling signal of telecommunication according to current sampling module to the pressure regulating module to guarantee that photodiode maintains throughout in the ideal operating voltage scope, in order to solve outside illumination change to photodiode's influence.
Drawings
Fig. 1 is a schematic diagram of a partial circuit structure of a conventional light receiving module;
fig. 2 is a schematic structural diagram of a light receiving module according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of another light receiving module according to an embodiment of the present invention;
fig. 4 is a schematic view of a working flow of a light receiving module according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a laser radar according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
Fig. 1 is a schematic diagram of a partial circuit structure of a conventional light receiving module, and referring to fig. 1, the light receiving module includes: photodiode 11, resistor 12 and power supply 13. The resistor 12 is electrically connected to the positive electrode of the power supply 13 and the cathode of the photodiode 11, respectively, and the anode of the photodiode 11 is electrically connected to the negative electrode of the power supply 13. The photodiode 11 is a P-N junction type photo detector diode for converting an optical pulse signal into an electrical pulse signal and outputting the electrical pulse signal, and when the photodiode 11 is in operation, the photodiode bias circuit amplifies the photoelectric signal by utilizing the avalanche multiplication effect of carriers after applying a proper reverse bias voltage to the P-N junction of the photodiode 11, so as to improve the detection sensitivity. The photodiode 11 is very sensitive to the accuracy and stability of the reverse bias voltage, and deviations from the optimal operating voltage range may degrade the performance of the photodiode 11 or cause irreversible damage. Therefore, applying a reverse bias voltage to the photodiode 11 with good stability, high precision and controlled is the key for the photodiode 11 to work normally.
In the prior art, a temperature sensor is usually arranged to compensate the influence of temperature on the leakage current of the photodiode 11, but neglect the influence of illumination on the leakage current of the photodiode 11, when the illumination changes, the photodiode 11 still deviates from the optimal operating voltage range, thereby influencing the operating performance of the photodiode 11. Specifically, as shown in fig. 1, when the photodiode 11 is switched from a dark environment to a light environment, in an initial state, the photodiode 11 is in the dark environment, the bias voltage across the photodiode 11 is the optimal bias voltage (the gain is the largest and is not broken down), when the photodiode 11 is switched into the light environment, due to the influence of light, the leakage current of the photodiode 11 increases, the current i becomes larger, the voltage across the resistor 12 increases, the voltage across the photodiode 11 decreases, at this time, the actual bias voltage of the photodiode 11 is smaller than the optimal operating voltage range, the gain of the photodiode 11 decreases, and the output electrical pulse signal decreases. Assuming that the photodiode 11 is in a light environment when the photodiode 11 is switched from a light environment to a dark environment, in an initial state, the photodiode 11 is in the light environment, the bias voltage across the photodiode 11 is the optimal bias voltage (the gain is the maximum and is just not broken down) of the photodiode 11, when the photodiode 11 is switched to the dark environment, due to light attenuation, the leakage current of the photodiode 11 is reduced, the current i is reduced, the voltage across the resistor 12 is reduced, the voltage across the photodiode 11 is increased, at this time, the actual bias voltage of the photodiode 11 is greater than the optimal operating voltage range, the photodiode 11 is broken down, at this time, the photodiode 11 and the resistor 12 are vibrated together, and an electric pulse is output, so that no useful signal exists in an electric pulse signal output by the photodiode 11.
Based on the technical problem, the embodiment of the utility model provides a light receiving module and laser radar, including photodiode, current sampling module and pressure regulating module, obtain the electric current in photodiode place return circuit and generate corresponding sampling signal of telecommunication through current sampling module, pressure regulating module adjusts photodiode's bias voltage according to the change of the sampling signal of telecommunication to guarantee that photodiode maintains the optimal operating voltage scope all the time, in order to solve outside illumination change to photodiode's influence.
Above is the core thought of the utility model, will combine the attached drawing in the embodiment of the utility model below, to the technical scheme in the embodiment of the utility model clearly, describe completely. Based on the embodiments in the present invention, under the premise that creative work is not done by ordinary skilled in the art, all other embodiments obtained all belong to the protection scope of the present invention.
Fig. 2 is the embodiment of the present invention provides a structural schematic diagram of a light receiving module, as shown in fig. 2, an embodiment of the present invention provides a light receiving module including a photodiode 21, a current sampling module 22 and a voltage regulating module 23. The current sampling module 22 is used for collecting the current of the loop where the photodiode 21 is located and generating a corresponding sampling electrical signal; the voltage regulating module 23 is respectively connected with the current sampling module 22, and the voltage regulating module 23 is used for regulating the voltage at two ends of the photodiode 21 within the working voltage range according to the change of the sampling electrical signal.
The embodiment of the utility model provides a light receiving module gathers the electric current in photodiode 21 place return circuit and generates corresponding sampling signal of telecommunication through current sampling module 22, and voltage regulation module 23 adjusts the voltage at photodiode 21 both ends in real time according to current sampling module 22's sampling signal of telecommunication to guarantee that photodiode 21 remains throughout at the optimal operating voltage scope, in order to solve the influence of outside illumination change to photodiode 21.
With continued reference to fig. 2, optionally, the current sampling module 22 includes a sampling current collecting terminal 221 and a sampling voltage output terminal 222, and the voltage regulating module 23 includes a sampling voltage receiving terminal 231 and a voltage regulating signal output terminal 232. The sampling current collecting terminal 221 includes a sampling current first collecting terminal and a sampling current second collecting terminal. The current sampling module 22 comprises a sampling resistor 41 and an amplifier 42, the sampling resistor 41 comprises a sampling current first collecting end 31 and a sampling current second collecting end 32, and the sampling current first collecting end 31 of the sampling resistor 41 is connected with the voltage regulating signal output end 232; the second sampling end 32 of the sampling current of the sampling resistor 41 is connected with the cathode of the photodiode 21; the sampling resistor 41 is connected in series to the circuit in which the photodiode 21 is located. The amplifier 42 includes a sampling current first receiving terminal 421, a sampling current second receiving terminal 422, and a sampling voltage output terminal 423, and the sampling voltage output terminal 222 is electrically connected to the sampling voltage receiving terminal 231. The first sampling current receiving terminal 421 is electrically connected to the first sampling current collecting terminal 31, and the second sampling current receiving terminal 422 is electrically connected to the second sampling current collecting terminal 32.
The sampling resistor 41 is connected in series to a loop in which the photodiode 21 is located, the sampling current collecting terminal 221 is electrically connected to a cathode of the photodiode 21 and the voltage regulating signal output terminal 232, and the sampling voltage output terminal 222 is electrically connected to the sampling voltage receiving terminal 231. The current sampling module 22 is used for collecting the current flowing through the photodiode 21, the sampling voltage receiving end 231 of the voltage regulating module 23 receives the sampling electrical signal output by the sampling voltage output end 222 of the current sampling module 22, and the voltage regulating module 23 dynamically regulates the output voltage of the voltage regulating signal output end 232 according to the sampling electrical signal output by the sampling voltage output end 222 of the current sampling module 22, so that the dynamic regulation of the bias voltage of the photodiode 21 according to the current of the photodiode 21 is realized, and the voltages at the two ends of the photodiode 21 are ensured to be within the working voltage range.
Illustratively, the sampling current first collecting terminal 31 of the sampling resistor 41 serves as the sampling current first collecting terminal of the current sampling module 22, the sampling current second collecting terminal 32 of the sampling resistor 41 serves as the sampling current second collecting terminal of the current sampling module 22, and the sampling voltage output terminal 423 of the amplifier 42 serves as the sampling voltage output terminal 222 of the current sampling module 22. The first sampling current receiving terminal 421 and the second sampling current receiving terminal 422 of the amplifier 42 respectively receive voltages of the first current collecting terminal 31 and the second current collecting terminal 32 of the sampling resistor 41, and the voltages of the first current collecting terminal 31 and the second current collecting terminal 32 of the sampling resistor 41 are differentiated to obtain voltages at two ends of the sampling resistor 41, where the voltages at two ends of the sampling resistor 41 are in direct proportion to the current of the sampling resistor 41, and since the sampling resistor 41 is connected in series with the photodiode 21 and the current of the sampling resistor 41 is the same as the current of the photodiode 21, the voltages at two ends of the sampling resistor 41 and the current of the photodiode 21 are in a certain proportion relationship, so as to convert the current of the photodiode 21 into a voltage signal. The amplifier 42 outputs the voltage signal obtained by difference to the voltage regulating module 23 through the sampling voltage output end 423, the voltage regulating signal output end 232 of the voltage regulating module 23 is electrically connected with the first sampling end of the sampling current of the current sampling module 22, and the voltage regulating module 23 adjusts the output voltage of the voltage regulating signal output end 232 according to the voltage signal output by the sampling voltage output end 423, so that the bias voltage of the photodiode 21 is regulated, and the photodiode 21 is ensured to be maintained in the optimal working voltage range all the time. Optionally, after the voltage received by the first sampling current receiving end 421 and the second sampling current receiving end 422 is differentiated by the amplifier 42, the differentiated voltage signal is amplified with a certain gain, and the amplified voltage signal is output to the voltage regulating module 23 through the sampling voltage output end 423, so as to improve the sensitivity of the light receiving module.
The utility model provides a light receiving module's current sampling module 22 also can adopt the circuit of other types, as long as can obtain photodiode 21's current value or magnitude of voltage to adjust output voltage in real time according to current value or magnitude of voltage can, thereby guarantee that photodiode 21 maintains throughout at the optimal operating voltage scope.
Fig. 3 is a schematic structural diagram of another light receiving module according to an embodiment of the present invention, as shown in fig. 3, optionally, the current sampling module 22 further includes: a first resistor 43, a second resistor 44, a third resistor 45 and a fourth resistor 46. The first end 431 of the first resistor 43 is electrically connected to the first sampling end 31 of the sampling resistor 41, the second end 432 of the first resistor 43 is electrically connected to the first end 451 of the third resistor 45 and the first receiving end 421 of the sampling current of the amplifier 42, and the second end 452 of the third resistor 45 is grounded. The first terminal 441 of the second resistor 44 is electrically connected to the second sampling terminal 32 of the sampling resistor 41, the second terminal 442 of the second resistor 44 is electrically connected to the first terminal 461 of the fourth resistor 46 and the second receiving terminal 422 of the amplifier 42, and the second terminal 462 of the fourth resistor 46 is grounded.
Since the leakage current of the photodiode 21 is generally of nA or uA level, when the current sampling module 22 is added, the signal-to-noise ratio of the photodiode 21 may be reduced, and since the bias voltage of the photodiode 21 is generally several tens volts to hundreds volts, the common-mode input voltage of the current sampling module 22 is also high. The embodiment of the utility model provides a light receiving module, through setting up first resistance 43 and third resistance 45 to and second resistance 44 and fourth resistance 46 carry out the partial pressure, improve current sampling module 22's input impedance, and reduce current sampling module 22's common mode input voltage, thereby make current sampling module 22 can not influence photodiode 21's normal work, improve light receiving module's SNR.
Optionally, the resistance of the first resistor 43 is R1, the resistance of the second resistor 44 is R2, the resistance of the third resistor 45 is R3, and the resistance of the fourth resistor 46 is R4, where R1/R3 is R2/R4.
The proportional relationship between the first resistor 43 and the third resistor 45 is the same as the proportional relationship between the second resistor 44 and the fourth resistor 46, which is helpful for the current sampling module 22 to directly obtain the current value of the photodiode 21, and simplifies the calculation process and the circuit structure.
Optionally, amplifier 42 is an instrumentation amplifier.
An instrumentation amplifier (INA) is an improved differential amplifier, having an input buffer, requiring no input impedance matching, and having the characteristics of very low dc offset, low drift, low noise, very high open loop gain, very large common mode rejection ratio, high input impedance, and the like. The embodiment of the utility model provides a light receiving module adopts instrumentation amplifier in order to improve light receiving module's accuracy nature and stability.
As shown in fig. 2 and fig. 3, optionally, the light receiving module provided in the embodiment of the present invention further includes: current limiting resistor 24, power supply 25, and voltage regulation module 23 further include voltage signal input 233. The anode of the photodiode 21 is electrically connected to the cathode of the power supply 25, the second end 242 of the current limiting resistor 24 is electrically connected to the sampling current collecting end 221 of the current sampling module 22, and the anode of the power supply 25 is electrically connected to the voltage signal input end 233 of the voltage regulating module 23.
Illustratively, as shown in fig. 2 and fig. 3, the anode of the photodiode 21 is electrically connected to the cathode of the power supply 25, the cathode of the photodiode 21 is connected to the first end electrical connection 241 of the current limiting resistor 24, the second end 242 of the current limiting resistor 24 is electrically connected to the sampling current collecting end 221 of the current sampling module 22, and the anode of the power supply 25 is electrically connected to the voltage signal input end 233 of the voltage regulating module 23. The power supply 25 provides a reverse bias voltage for the photodiode 21 to ensure that the photodiode 21 can work normally, and the power supply 25 can also supply power for the voltage regulating module 23. In other embodiments, a power supply built in the voltage regulating module 23 may be adopted. The current limiting resistor 24 plays a role of overload protection, specifically, when the power of the input optical pulse signal is too large, the photodiode 21 generates a large current, and the voltage drop across the current limiting resistor 24 increases accordingly, so that the reverse bias voltage of the photodiode 21 is reduced, and overcurrent damage of the photodiode 21 caused by the fact that the photodiode 21 receives the optical pulse signal with too large power is avoided.
Optionally, the resistance of the sampling resistor 41 is R5, and the resistance of the current limiting resistor 24 is R6, where R1/R5 is greater than or equal to 10, R2/R5 is greater than or equal to 10, and R6 is greater than R5.
The first resistor 43 and the second resistor 44 are both high-resistance resistors, and the resistance value R1 of the first resistor 43 and the resistance value R2 of the second resistor 44 are much larger than the resistance value R5 of the sampling resistor 41, so that the common-mode voltage of the current sampling module 22 is reduced while the high input impedance of the current sampling module 22 is ensured. Furthermore, the resistance of the photodiode 21 is R7, which can make R1/(R5+ R6+ R7) equal to or more than 10, and R2/(R5+ R6+ R7) equal to or more than 10. For example, the resistance R5 of the sampling resistor 41 may be 1K Ω, the resistance R6 of the current limiting resistor 24 may be 500K Ω, and the resistance R1 of the first resistor 43 and the resistance R2 of the second resistor 44 may be M Ω. By making the resistance value R6 of the current limiting resistor 24 larger than the resistance value R5 of the sampling resistor 41, the influence of the sampling resistor 41 on the photodiode 21 can be further reduced.
As shown in fig. 2 and fig. 3, optionally, the light receiving module according to an embodiment of the present invention further includes a capacitor 26, a first end 261 of the capacitor 26 is electrically connected to the first end 241 of the current limiting resistor 24 and the cathode of the photodiode 21, respectively, and a second end 262 of the capacitor 26 serves as an output end of the light receiving module.
In this case, the capacitor 26 is provided to reduce the reverse bias voltage of the photodiode 21 more quickly when the power of the input optical pulse signal is increased, thereby ensuring that the photodiode 21 is not damaged.
Optionally, the voltage regulating module 23 is configured to adjust the output voltage of the voltage regulating signal output end 232 when the variation of the sampled electrical signal is greater than the first preset value.
Illustratively, assuming that the photodiode 21 is in a dark environment when the photodiode 21 is switched from a dark environment to a light environment, in an initial state, the photodiode 21 is in a dark environment, the bias voltage across the photodiode 21 is an optimal bias voltage (with the largest gain and without breakdown), when the photodiode 21 is switched into a light environment, due to the influence of light, the leakage current of the photodiode 21 increases, the voltage across the sampling resistor 41 increases, the voltage across the photodiode 21 decreases, at this time, the actual bias voltage of the photodiode 21 is smaller than the optimal operating voltage range, the sampled electrical signal output by the sampling voltage output terminal 222 of the current sampling module 22 increases, and when the sampled electrical signal increases to a certain degree (when the amount of change of the sampled electrical signal received by the sampling voltage receiving terminal 231 of the voltage regulating module 23 is larger than a first preset value relative to the amount of change of the sampled electrical signal received by the sampling voltage receiving terminal 231 in the initial, the voltage regulation module 23 increases the output voltage so that the voltage across the photodiode 21 returns to the optimal operating voltage range. Assuming that the photodiode 21 is in a light environment when the photodiode 21 is switched from a light environment to a dark environment, the bias voltage across the photodiode 21 is the optimal bias voltage (the gain is the largest and is just not broken down) of the photodiode 21 in the light environment in the initial state, when the photodiode 21 is switched to the dark environment, the leakage current of the photodiode 21 is reduced due to the decrease of light, the voltage across the sampling resistor 41 is reduced, the voltage across the photodiode 21 is increased, at this time, the actual bias voltage of the photodiode 21 is greater than the optimal operating voltage range, the sampled electrical signal output by the sampling voltage output terminal 222 of the current sampling module 22 is reduced, and when the sampled electrical signal output by the sampling voltage output terminal 222 is reduced to a certain degree (when the amount of change of the sampled electrical signal received by the sampling voltage receiving terminal 231 of the voltage regulating module 23 is greater than the first preset value relative to the sampled electrical signal received by the sampling, the voltage regulation module 23 reduces the output voltage so that the voltage across the photodiode 21 returns to the optimal operating voltage range. In the initial state, the bias voltage across the photodiode 21 is the optimal bias voltage for the photodiode 21. The first preset value can be set according to the actual requirements of the system circuit.
The embodiment of the utility model provides a light receiving module, when the variable quantity of the sampling signal of telecommunication received at pressure regulating module 23 is greater than first default, the voltage at photodiode 21 both ends was just adjusted to pressure regulating module 23 for pressure regulating module 23 has certain hysteresis, and the voltage that allows photodiode 21 both ends is undulant in the certain limit, thereby avoids frequently adjusting the voltage at photodiode 21 both ends, improves whole light receiving module's stability.
Optionally, the photodiode 21 is an avalanche photodiode, a single photon avalanche diode, or a PIN photodiode.
Wherein, the Avalanche Photodiode (APD) has the advantages of ultra-low noise, high speed and high mutual impedance gain; a Single Photon Avalanche Diode (SPAD) has Single Photon detection capability; the PIN photodiode has the advantages of small junction capacitance, short transit time, high sensitivity and the like. Those skilled in the art can select other photodiodes according to the actual application requirements, and the embodiment of the present invention is not limited to this.
Fig. 4 is a schematic diagram of a work flow of a light receiving module provided in an embodiment of the present invention, as shown in fig. 4, after the light receiving module starts to work, along with the change of background illumination, the current sampled by the current sampling module 22 changes, and the voltage regulating module 23 determines whether the bias voltage of the photodiode 21 is normal, and if the bias voltage of the photodiode 21 is normal, the output voltage of the voltage regulating signal output end 232 is not changed; if the bias voltage of the photodiode 21 is not normal, the output voltage of the signal output terminal 232 is adjusted to ensure that the photodiode 21 is always maintained in the optimal operating voltage range. If the variation of the sampled electrical signal provided by the current sampling module 22 and received by the voltage regulating module 23 relative to the sampled electrical signal received by the sampled voltage receiving end 231 in the initial state is smaller than or equal to the first preset value, it is determined that the bias voltage of the photodiode 21 is normal; if the variation of the sampled electrical signal received by the voltage regulating module 23 from the sampled electrical signal received by the sampled voltage receiving end 231 in the initial state is smaller than or equal to the first preset value, it is determined that the bias voltage of the photodiode 21 is abnormal.
Optionally, the voltage regulating module 23 includes a DC-DC converter, and the DC-DC converter can convert the DC voltage output by the power supply 25 into a DC voltage with a desired voltage value and output the DC voltage.
The embodiment of the utility model provides a light receiving module gathers photodiode 21's electric current through current sampling module 22 to go up the electric current with photodiode 21 and feed back to voltage regulation module 23 with certain form's signal, voltage regulation module 23 comes real-time regulation output voltage according to current sampling module 22's output signal, thereby adjustment photodiode 21's bias voltage, guaranteed that photodiode 21 maintains the optimal operating voltage scope all the time, thereby solve the influence of outside illumination change to photodiode 21. Furthermore, adopt the embodiment of the utility model provides a light receiving module when solving the problem that arouses photodiode 21 leakage current change and lead to photodiode 21 operating voltage to change by outside illumination, also can solve the problem that the photodiode 21 leakage current change caused because temperature or other factors arouse to need not to set up temperature monitoring circuit again, make whole light receiving module structure comparatively simple and reduced circuit cost.
Based on the same inventive concept, the embodiment of the present invention further provides a laser radar, which includes a light emitting module and further includes any light receiving module provided by the above embodiment. Specifically, fig. 5 is the utility model provides a lidar's schematic structure diagram, as shown in fig. 5, the utility model provides a lidar includes optical transmission module 51 and optical receiving module 52, and optical receiving module 52 is the optical receiving module that above-mentioned arbitrary embodiment provided, and the explanation of the same or corresponding structure and the term with above-mentioned embodiment is no longer repeated here. The optical transmitting module 51 is used for generating a laser beam and scanning the scanning area; the light receiving module 52 is used for receiving a reflected light beam formed by the object in the scanning area reflecting the laser beam, so as to realize laser detection or ranging.
It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.
Claims (10)
1. The light receiving module is characterized by comprising a photodiode, a current sampling module and a voltage regulating module; the current sampling module is used for collecting the current of a loop where the photodiode is located and generating a corresponding sampling electric signal; the voltage regulating module is respectively connected with the current sampling module and used for regulating the voltages at two ends of the photodiode within a working voltage range according to the change of the sampling electric signal.
2. The light receiving module of claim 1, wherein the current sampling module comprises a sampling current collecting terminal and a sampling voltage output terminal, and the voltage regulating module comprises a sampling voltage receiving terminal and a voltage regulating signal output terminal; the sampling current acquisition end comprises a sampling current first acquisition end and a sampling current second acquisition end;
the current sampling module comprises a sampling resistor and an amplifier, the sampling resistor comprises a first sampling current collecting end and a second sampling current collecting end, and the first sampling current collecting end of the sampling resistor is connected with the voltage regulating signal output end; a second sampling end of the sampling current of the sampling resistor is connected with the cathode of the photodiode; the sampling resistor is connected in series with a loop where the photodiode is located; the amplifier comprises a first sampling current receiving end, a second sampling current receiving end and the sampling voltage output end; the sampling voltage output end is electrically connected with the sampling voltage receiving end;
the first sampling current receiving end is electrically connected with the first sampling current collecting end, and the second sampling current receiving end is electrically connected with the second sampling current collecting end.
3. The light-receiving module according to claim 2, wherein the current sampling module further comprises:
the circuit comprises a first resistor, a second resistor, a third resistor and a fourth resistor;
the first end of the first resistor is electrically connected with the first sampling end of the sampling current of the sampling resistor, the second end of the first resistor is respectively and electrically connected with the first end of the third resistor and the first receiving end of the sampling current of the amplifier, and the second end of the third resistor is grounded;
the first end of the second resistor is electrically connected with the second sampling end of the sampling current of the sampling resistor, the second end of the second resistor is respectively electrically connected with the first end of the fourth resistor and the second receiving end of the sampling current of the amplifier, and the second end of the fourth resistor is grounded.
4. The light receiving module as claimed in claim 3, wherein the first resistor has a resistance of R1, the second resistor has a resistance of R2, the third resistor has a resistance of R3, and the fourth resistor has a resistance of R4;
wherein, R1/R3 ═ R2/R4.
5. The light receiving module according to claim 4, characterized in that the light receiving module further comprises:
a current limiting resistor and a power supply;
the voltage regulating module also comprises a voltage signal input end;
the anode of the photodiode is electrically connected with the cathode of the power supply, and the second end of the current limiting resistor is electrically connected with the sampling current acquisition end of the current sampling module;
and the positive pole of the power supply is electrically connected with the voltage signal input end of the voltage regulating module.
6. The light receiving module of claim 5, wherein the sampling resistor has a resistance of R5, and the current limiting resistor has a resistance of R6, wherein R1/R5 is greater than or equal to 10, and R2/R5 is greater than or equal to 10; r6 > R5.
7. The light receiving module according to claim 5, characterized in that the light receiving module further comprises: a capacitor;
the first end of the capacitor is respectively connected with the first end of the current-limiting resistor and the cathode of the photodiode, and the second end of the capacitor is used as the output end of the light receiving module.
8. The optical receiving module of claim 1, wherein the voltage regulating module is configured to regulate the voltage across the photodiode within a working voltage range when a variation of the sampled electrical signal is greater than a first preset value.
9. The light-receiving module according to claim 1, wherein the photodiode is an avalanche photodiode, a single photon avalanche diode, or a PIN photodiode.
10. A lidar comprising a light emitting module, further comprising a light receiving module according to any one of claims 1 to 9; the light emitting module is used for generating laser beams and scanning the scanning area; the light receiving module is used for receiving a reflected light beam formed by reflecting the laser beam by an object in a scanning area.
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| CN201921501182.5U CN210864034U (en) | 2019-09-10 | 2019-09-10 | Light receiving module and laser radar |
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| CN201921501182.5U CN210864034U (en) | 2019-09-10 | 2019-09-10 | Light receiving module and laser radar |
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