Photoelectric conversion circuit for omnidirectional photoelectric receiver

Abstract

The utility model relates to the technical field of photoelectricity, in particular to a photoelectric conversion circuit for an omnidirectional photoelectric receiver. Comprising a multi-stage signal amplification circuit, a signal filtering and interference source processing module, a pulse level output circuit and a power supply unit module, the multi-stage signal amplification circuit is used for amplifying the current signal and converting the current signal into a voltage signal with a symmetrical waveform; the signal filtering and interference source processing module is used for carrying out de-noising processing on the voltage signal in the photoelectric conversion circuit; the pulse level output circuit adopts a hysteresis comparator circuit design and is used for converting the voltage signal into a digital pulse signal; the power supply unit module comprises a single-power-supply low-ripple power supply unit and a reference voltage source unit, the single-power-supply low-ripple power supply unit is used for providing power for the photoelectric conversion circuit, and the reference voltage source unit is used for providing output limiting level. The photoelectric conversion circuit provided by the utility model can effectively adapt to an omnidirectional photoelectric receiver, and realizes a high-speed photoelectric conversion function.

Description

Technical Field

[0001] The utility model relates to the field of optoelectronic technology, in particular to a photoelectric conversion circuit for an omnidirectional photoelectric receiver. Background Art

[0002] The Accurate Laser Positioning System (ALPS) is a new type of distributed network intersection coordinate measurement system developed to solve the problem of indoor large-scale space measurement and positioning. It is mainly used for geometric parameter measurement of large-scale parts, three-dimensional inverse measurement of surface structure, surface defect detection and guidance and positioning of indoor AGV. The photoelectric receiver is the front-end optical signal receiving unit of ALPS, and its performance directly affects the measurement accuracy and use of the system. The working mechanism of the photoelectric detector in the photoelectric receiver is to convert the photon energy of various light sources at the front end into a quantifiable electrical signal based on the photosensitivity effect. It has the characteristics of high sensitivity, good spectral characteristics, high detection efficiency and small size, and is widely used in industrial electronics, measuring instruments, fiber optic communications and other fields.

[0003] At present, the commonly used design forms in photoelectric conversion circuits are direct voltage amplification mode, photovoltaic mode and photoconductivity mode. The voltage signal output by the direct voltage amplification mode varies in proportion to the photosensitive area of ​​the silicon photocell, while the ALPS system requires that the output pulse signal be symmetrical. This extraction method will result in a large deviation in the final extracted feature position and is not suitable for the measurement requirements of omnidirectional receivers. In the photovoltaic mode, the voltage flowing through the positive and negative electrodes of the silicon photocell is 0V, and no reverse bias voltage is applied to it. In the ideal mode, it is believed that there will be no dark current passing through it, and it has good noise conditions, linear conditions and sensitivity conditions. However, its response speed is relatively low, and it is not suitable for high-speed signal acquisition. Adding a reverse bias voltage at both ends of the silicon photocell gives it an advantage in processing high-speed signals. However, due to the presence of the bias voltage, a dark current will flow through it, resulting in an increase in its noise. Utility Model Content

[0004] In order to solve the problems existing in the prior art, the utility model provides a photoelectric conversion circuit for an omnidirectional photoelectric receiver. The scheme includes: a multi-stage signal amplification circuit, a signal filtering and interference source processing module, a pulse level output circuit, and a power supply unit module; the multi-stage signal amplification circuit is used to amplify the current signal and convert it into a voltage signal with a symmetrical waveform; the signal filtering and interference source processing module is used to denoise the voltage signal in the photoelectric conversion circuit; the pulse level output circuit adopts a hysteresis comparator circuit design to convert the voltage signal into a digital pulse signal; the power supply unit module includes a single power supply low ripple power supply unit and a reference voltage source unit, which are used to provide power for the photoelectric conversion circuit. The photoelectric conversion circuit proposed in the utility model can effectively adapt to the omnidirectional photoelectric receiver and realize the high-speed photoelectric conversion function.

[0005] The utility model adopts the following technical scheme, a photoelectric conversion circuit for an omnidirectional photoelectric receiver, comprising: a multi-stage signal amplification circuit, a signal filtering and interference source processing module, a pulse level output circuit, and a power supply unit module;

[0006] The multi-stage signal amplification circuit is used to amplify the current signal and convert it into a voltage signal with a symmetrical waveform;

[0007] The signal filtering and interference source processing module is used to perform noise removal on the voltage signal in the photoelectric conversion circuit;

[0008] The pulse level output circuit adopts a hysteresis comparator circuit design to convert the voltage signal into a digital pulse signal;

[0009] The power supply unit module comprises a single-power low-ripple power supply unit and a reference voltage source unit, which are used to provide power for the photoelectric conversion circuit.

[0010] Furthermore, the multi-stage signal amplification circuit includes: a photodiode, an I / V conversion module, a primary signal amplification module and a secondary signal amplification module.

[0011] Furthermore, the multi-stage signal amplification circuit further includes:

[0012] Establishing an equivalent circuit model of a multi-stage signal amplification circuit and setting parameters in the equivalent circuit model;

[0013] The equivalent circuit model is input into simulation software for simulation, and the simulation software is used to obtain a recommended circuit for the multi-stage signal amplification circuit.

[0014] Furthermore, the parameters in the equivalent circuit model include: series resistance R S , parallel resistance R SH , the photocurrent I generated by the light source irradiating the detector surface PD and junction capacitance CJ .

[0015] Furthermore, the pulse level output circuit adopts a hysteresis comparator circuit design, and the comparator adopts a high-speed comparator of the SGM8740 model.

[0016] Furthermore, the reference voltage source unit is used to provide an output limit level, specifically:

[0017] The reference voltage source unit provides a 3.3V limit level for the hysteresis comparator of the pulse level output circuit;

[0018] When the input signal in the hysteresis comparator is within the threshold width, a pulse signal with a reference voltage of 3.3V is output;

[0019] When the input signal in the hysteresis comparator exceeds the threshold width, the input signal is filtered out.

[0020] The beneficial effects of the utility model are as follows: the photoelectric conversion circuit proposed in the utility model takes the pulse signal as the core design basis, and performs system simulation through a multi-stage amplification circuit to obtain a recommended circuit model, which can ensure the frequency and noise of the output signal while meeting the output signal strength. The signal filtering and interference source processing module can effectively reduce the noise in the process of signal inflow and outflow, and improve the signal-to-noise ratio of the circuit. The pulse level output circuit adopts a high-speed comparator and a unique hysteresis comparator design. It can set a suitable threshold width in combination with the sharp pulse interference existing in the circuit conversion, and cooperate with the design of the reference voltage source to ensure that within the set threshold range, a stable 3.3V pulse signal can be continuously output, which can achieve high-speed output while reducing power consumption. The power supply unit module adopts a single power supply, which effectively reduces the complexity of power supply, thereby further helping to reduce the size of the photoelectric detection board. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0022] Figure 1 This is a schematic diagram of the structure of a photoelectric conversion circuit for an omnidirectional photoelectric receiver according to an embodiment of the utility model;

[0023] Figure 2 This is a schematic diagram of a multi-stage amplification module structure of an embodiment of the utility model;

[0024] Figure 3A photoelectric detection equivalent circuit diagram of an embodiment of the utility model;

[0025] Figure 4 A schematic diagram of the relationship between a signal receiving distance and a photocurrent according to an embodiment of the utility model;

[0026] Figure 5 A schematic diagram of an ADI circuit online simulation design tool interface according to an embodiment of the utility model;

[0027] Figure 6 A schematic diagram of a photodiode circuit model according to an embodiment of the utility model;

[0028] Figure 7 A schematic diagram of a circuit pulse response simulation of an embodiment of the utility model;

[0029] Figure 8 A frequency response simulation schematic diagram of an embodiment of the utility model;

[0030] Fig. 9 A schematic diagram of spectrum noise density simulation of an embodiment of the utility model;

[0031] Fig.10 A schematic diagram of circuit signal-to-noise ratio simulation parameters of an embodiment of the utility model;

[0032] Fig.11 A schematic diagram of a multi-stage amplifier circuit according to an embodiment of the utility model;

[0033] Fig.12 A circuit schematic diagram of a power supply unit module according to an embodiment of the utility model;

[0034] Fig.13 A schematic diagram of a pulse level generating circuit according to an embodiment of the utility model;

[0035] Fig.14 A schematic diagram of a signal measurement distance experiment result according to an embodiment of the present utility model. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0037] The ALPS transmitting base station has two linear lasers with a wavelength of 850nm installed on its rotating head. Driven by a motor, it rotates 360° around the base station for scanning. The main function of the ALPS system sensor unit is to detect the laser signal emitted by the base station, and finally convert the optical signal into a digital pulse signal that can be directly collected by the processor through photoelectric conversion, signal conditioning and amplification, and level conversion. Under long-distance measurement conditions, the light intensity of the signal detected by the detector and the pulse width of the signal itself directly determine the signal amplification factor, signal bandwidth and other design indicators of the sensor hardware design. In this embodiment, a high-speed photoelectric detector is used to receive the laser signal emitted by the base station to realize the high-speed photoelectric conversion function. The laser signal emitted by the base station is mainly divided into two types: fan laser signal and pulse laser signal. For the signal light intensity, a photosensitive surface of 5mm is used. 2 The photoelectric detector is used as the receiving end, and the existing photoelectric conversion sensor is used to detect the photocurrent of the laser signal under different distance conditions using an oscilloscope to obtain the photocurrent values ​​under different distance conditions. Figure 4 shown.

[0038] Depend on Figure 4 Analysis shows that as the signal receiving distance increases, the intensity of both types of lasers decays at a faster rate; among them, the pulse signal decays relatively faster. When it is above 20m, the photocurrent is reduced to less than 1uA. This is mainly because the pulse signal is generated by a pulse laser with a scattering angle of 120°, which is a heat dissipation light source, while the fan laser signal is generated by a collimated line laser, which is a collimated light source; as the distance increases, the coverage range of the heat dissipation light source is much larger than that of the line laser light source, so the screening speed is also much faster than that of the line laser light source. From the signal characteristics, the signal waveform formed by the line laser scanning the photodetector once is a Gaussian waveform with symmetrical sides, and the waveform width is between 5us-100us with different distances; the pulse signal is a typical pulse waveform with a waveform rising edge of 50ns and a waveform width of 200ns. Therefore, the pulse waveform requires a higher bandwidth in the photoelectric conversion process. When designing the photoelectric conversion circuit, the pulse signal is used as the circuit design basis to ensure that its signal waveform is not distorted.

[0039] A typical photoelectric conversion circuit is mainly composed of a photodetector, an IV conversion circuit, a signal amplification circuit and a power supply circuit; among them, the photodetector is a sensing unit for laser signals, and its response speed, photosensitive area and photoelectric conversion efficiency all play a key role in the distortion-free amplification of the waveform; the main types of photodetectors are photodiodes and avalanche diodes; among them, in terms of response speed, avalanche diodes are faster than photodiodes and can reach more than GHZ, but in actual use, avalanche diodes are more easily saturated and require a reverse bias voltage of hundreds of volts to be added to the cathode, which is troublesome to use and has high noise; while the photodiode can reach MHz in response speed, the reverse bias voltage is between a few volts and more than ten volts, and the dark current is at the pA level, which is more suitable for the photoelectric detection circuit of the utility model. Therefore, this embodiment selects a silicon photocell as the core detection device. When the reverse bias voltage is 10V, its response speed can reach 11ns, and the dark current is 0.1nA. The specific parameters are shown in Table 1.

[0040] Table 1 Schematic diagram of silicon photovoltaic cell parameters

[0041]

[0042] As a direct means of acquiring the local space front-end optical signal of the entire ALPS system, the photoelectric receiver processes the laser analog signal in the measurement field and converts it into a pulse digital signal with high signal-to-noise ratio and good waveform for the I / O port of the embedded processing platform to collect and complete subsequent solutions. Therefore, a signal conditioning circuit is designed and built to extract the measurement base station laser signal. Through multi-stage amplification, analog-to-digital conversion, noise filtering and other processing, the system measurement characteristic parameters are obtained and input into the spatial measurement positioning model to ensure the system measurement accuracy. This becomes a crucial link in the entire information processing process.

[0043] There are differences in the structural forms of planar receivers, target measurement receivers, and full-range receivers, but they are almost the same in realizing the photoelectric conversion hardware circuit. The latter two receivers are evolved from the configuration combination based on the planar receiver. The functions realized by the photoelectric conversion hardware circuit mainly include:

[0044] The weak current signal generated by the front-end silicon photocell is amplified and converted into a voltage amplitude signal with symmetrical waveform;

[0045] The I / O port of the data processing platform collects TTL level signals, and the analog laser signals in the measurement field need to be converted into accurate digital pulse signals for the subsequent data processing;

[0046] To ensure that the presence of noise is reduced as much as possible during the process of signal flow input to output and that the hardware circuit has a higher signal-to-noise ratio, it is necessary to design a reasonable filtering circuit.

[0047] Through the above analysis and design, the photoelectric conversion hardware circuit mainly completes the task of extracting high-speed low-frequency signals. The schematic diagram of the photoelectric conversion circuit structure of the utility model for an omnidirectional photoelectric receiver is as follows: Figure 1 As shown, it includes a multi-stage signal amplification circuit, a signal filtering and interference source processing module, a pulse level output circuit, and a power supply unit module.

[0048] Specifically, when designing a signal amplification module, we can first establish a simulation model of the circuit, including an equivalent circuit model of the photodetector and a subsequent amplification circuit model, and then use simulation software to simulate the characteristics of the amplification circuit to ensure that the circuit bandwidth and noise meet the design requirements. The composition of a typical multi-stage amplification module is as follows: Figure 2 As shown, it mainly includes two parts: an I / V conversion circuit and a signal amplification circuit. In this embodiment, a circuit model of the amplification module is established and simulation software is used to design and verify the response speed and noise level of the circuit.

[0049] When conventional circuit simulation software is used to simulate a transimpedance amplifier, a diode model is simply used to replace the photodiode. The structural characteristics and photocurrent characteristics of the reverse diode cannot be reversed, and thus the specific parameters of the transimpedance amplifier cannot be designed. Therefore, the utility model first establishes an equivalent circuit for the selection of a photodetector, and sets the photocurrent parameters and the response speed of the diode according to actual conditions. The photodiode is theoretically a current source, and the current is mainly determined by the photocurrent generated by the photosensitive surface. When establishing the model, this embodiment mainly considers the effects of parameters such as the photocurrent IPD, junction capacitance CJ, parallel resistance RSH, and series resistance and bias voltage. Its equivalent circuit is as follows: Figure 3 As shown, the parameters of the established model represent: R S is the series resistance; R SH is the shunt resistor, the resistance value determines the noise characteristics and the load input current; I PD The photocurrent generated by the light source irradiating the detector surface under ideal conditions is determined by the laser intensity and the illuminated area; C J Junction capacitance, C J The value determines the response speed of the diode. The smaller the value, the faster the response speed. Generally, the larger the photosensitive area, the larger the junction capacitance, the slower the response speed, and the larger the dark current; the larger the reverse bias voltage, the larger the junction capacitance, the slower the response speed, and the larger the dark current; therefore, when designing the circuit, it is necessary to select a detector with a suitable photosensitive surface and add a suitable reverse bias voltage to meet the output signal strength while ensuring the frequency and noise size of the output signal.

[0050] After establishing the photodetector equivalent model (i.e., the equivalent circuit model of the multi-stage signal amplification circuit) in this embodiment, the model is imported into the simulation software, the amplification circuit is added and the entire model is simulated. In this embodiment, optional simulation software includes Multisim, Proteus, etc.; thereby verifying the circuit performance.

[0051] The subsequent photoelectric conversion circuit of the detector includes I / V conversion, a primary amplification circuit, and a secondary amplification circuit. The amplification ratio distribution of each circuit and the matching of capacitors and resistors play a decisive role in the noise, amplitude, and symmetry of the final output signal. Traditional simulation software can only simulate and calculate the designed circuit, and cannot automatically design and adapt the circuit, which makes it difficult to select the amplifier and the parameter matching is inaccurate, which ultimately causes the designed circuit to fail to achieve the required output characteristics. Therefore, in order to obtain the most reasonable matching parameters for each module in actual application scenarios, this embodiment uses a dedicated diode amplifier circuit design tool in the ADI Precision Studio toolbox to design the amplifier circuit. By inputting the actual photocurrent value and detector parameters, setting the output amplitude and signal bandwidth, and automatically analyzing the parameters of each module and key values ​​such as the output signal bandwidth and noise level, the ADI circuit online simulation design tool interface is shown below. Figure 5 As shown, the tool first inputs the diode parameters and the actual photocurrent size, and finally obtains the recommended circuit and circuit output characteristics by setting the output waveform parameters and the amplification level.

[0052] In a specific embodiment of the utility model, the photocurrent at 20m is about 1.5uA, the actual parameters of the silicon photocell are selected as the photodiode parameters, the target speed is set to 200ns, the output voltage is 500mV, the amplification level is 2, and the recommended circuit obtained by automatic analysis is as follows Figure 6 As shown in the figure, it can be seen that the circuit mainly includes a photodiode, a transimpedance amplifier and a two-stage amplification and filtering circuit. Among them, the first-stage transimpedance amplifier uses the AD8065 FastFET operational amplifier with a -3dB bandwidth of 145MHz (G=+1) and a noise of only According to the empirical formula of signal bandwidth and signal rise time, Δf=0.35 / t r It can be seen that: when the rising edge of the input pulse signal is 50ns, Δf=7MHz, and the AD8065 bandwidth f>>Δf, which meets the design requirements.

[0053] The formula for calculating the output voltage of the transimpedance amplifier is:

[0054] U o1 =-R f I

[0055] Under the set 1.5uA input current condition, the transimpedance amplifier output voltage is -19.05mV, the secondary circuit is an inverting amplifier circuit, and the amplification formula is:

[0056] U o2 =-R f / Rs×U in

[0057] Among them U in =-19.05mV, R f / R s =309 / 11.8=26.18 times, the final output voltage is 498.85mV, which meets the design requirements; the circuit parameters are input into the ADI online simulation software to perform photodiode circuit simulation analysis and design, and the circuit pulse response simulation is obtained as follows Figure 7 As shown; the frequency response simulation is as follows Figure 8 As shown, the frequency response curve is a Bode plot, which represents the circuit performance within the input frequency sweep range; the spectrum noise density simulation is as follows Fig. 9 As shown in Figure 1, the spectral noise density shows the noise contribution of each noise source generator in the circuit within the frequency range; the circuit signal-to-noise ratio (SNR) simulation parameter diagram is shown in Figure 1. Fig.10 As shown, the noise performance of the entire circuit is obtained, and the results of a single noise source are detailed. It can be seen that the rise time under this parameter is 59ns, the overcharge is 0.2%, and the waveform symmetry is good; the cutoff frequency of the circuit model is 6.23MHz, and the noise value is less than 6mV, which meets the actual hardware circuit design requirements.

[0058] In this embodiment, the dual power supply of the analog amplifier is further changed to a single power supply. By adding a bias voltage to the input end of the transimpedance amplifier, the reference voltage of the reverse amplification output is raised, thereby ensuring the integrity of the output signal, reducing the complexity of the system power supply, and also reducing the size of the photoelectric detection board. The final multi-stage amplifier circuit schematic diagram is as follows: Fig.11 As shown, the circuit schematic diagram of the power supply unit module is as follows Fig.12 shown.

[0059] After multiple stages of amplification and conditioning, the analog signal of the previous stage needs to be converted into a pulse signal for collection by the processor I / O port. For the ALPS system, the extracted data has high requirements for the time delay and waveform stability of the pulse signal. In this embodiment, the generation of the pulse level adopts a hysteresis comparator circuit design. By designing the hysteresis voltage parameters, it is ensured that the system can still output stably when there is glitch signal interference. Specifically, the SGM8740 high-speed comparator is selected. This is a single high-speed, low-power comparator with a fast propagation delay of 45ns. The device is optimized for low-voltage operation of 3V or 5V power supplies, and consumes only 155μA of power supply current. It is also compatible with CMOS and TTL logic; through the hysteresis comparison circuit, the electrical signal amplified by the front stage can be converted into a pulse level signal of about 3.3V for collection by the high-speed signal processing platform. CLREF2018 is an ultra-low noise, low-temperature drift voltage reference chip. Its output high-precision 2.5V voltage is used as the VREF reference voltage source input. It uses a small 3-pin SOT23 package and can operate between 2.8V and 5.5V. The operating current is 270μA and the maximum load current is 10mA. The voltage reference chip is used to filter out the existing periodic background noise to achieve modulation of the front-end laser signal. The pulse level generation circuit design is as follows Fig.13 shown.

[0060] During the measurement process of the ALPS positioning system, the amplitude of the signal is related to factors such as changes in the external environment and the distance between the base station and the sensor. The signal waveform changes frequently, and the size of the dynamic threshold level changes with the changes in ambient light, thereby improving the signal's anti-interference ability and ensuring the correctness of the pulse output. When the silicon photocell receives a laser signal, it will also be affected by environmental factors, such as the incidence of stray light in the measurement field, reflection of the laser from the transmitter head, the influence of air temperature and humidity, nearby electromagnetic interference sources, etc. Therefore, this embodiment proposes to add an 850nm narrow-band filter for ambient light compensation to reduce background noise fluctuations. Experiments have shown that after adding the filter, the noise amplitude is reduced from 500mV to 30mV, thereby improving signal stability.

[0061] In this embodiment, a transmitting base station with a rotation speed of 3000 r / min is fixed in front of the measurement field, and the distance between the receiver and the base station is adjusted within a range of 4m to 22m from the base station for testing. The relationship between the waveform amplitude of the measurement signal and the measurement distance is obtained as follows: Fig.14 As shown, as the distance increases, the signal amplitude decreases sharply. Within the range of 14m, the signal output amplitude is greater than 1V, and within the range of 22m, the signal output amplitude is greater than 500mV. Since the threshold level range of the high-speed comparison circuit is about 300mV, pulse signals can be output within the range of 22m. It can be seen that the circuit proposed by the utility model is fully capable of meeting the actual use within the range of 22m.

[0062] In a specific embodiment of the present invention, after completing the design of the receiver hardware circuit schematic diagram through Altium Designer2018 software, layout and wiring, electrical rule checking and other steps are performed to complete the drawing of the PCB circuit diagram of the photoelectric receiver and the connector adapter board. According to the signal transmission requirements, the omnidirectional receiver photoelectric conversion circuit adopts a compact 4-layer board design, and the interface adapter board adopts a 2-layer board design. Finally, the board is cast and welded to obtain a physical hardware circuit board card.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A photoelectric conversion circuit for an omnidirectional photoelectric receiver, characterized in that: include: Multi-stage signal amplification circuit, signal filtering and interference source processing module, pulse level output circuit, power supply unit module; The multi-stage signal amplification circuit is used to amplify the current signal and convert it into a voltage signal with a symmetrical waveform; The signal filtering and interference source processing module is used to perform noise removal on the voltage signal in the photoelectric conversion circuit; The pulse level output circuit adopts a hysteresis comparator circuit design to convert the voltage signal into a digital pulse signal; The power supply unit module includes a single power low ripple power supply unit and a reference voltage source unit. The single power low ripple power supply unit is used to provide power for the photoelectric conversion circuit, and the reference voltage source unit is used to provide an output limit level.

2. The photoelectric conversion circuit for an omnidirectional photoelectric receiver according to claim 1, characterized in that: The multi-stage signal amplification circuit comprises: a photodiode, an I / V conversion module, a primary signal amplification module and a secondary signal amplification module.

3. The photoelectric conversion circuit for an omnidirectional photoelectric receiver according to claim 2, characterized in that: The multi-stage signal amplification circuit further includes: Establishing an equivalent circuit model of a multi-stage signal amplification circuit and setting parameters in the equivalent circuit model; The equivalent circuit model is input into simulation software for simulation, and the simulation software is used to obtain a recommended circuit for the multi-stage signal amplification circuit.

4. The photoelectric conversion circuit for an omnidirectional photoelectric receiver according to claim 3, characterized in that: The parameters in the equivalent circuit model include: series resistance R S , parallel resistance R SH , the photocurrent I generated by the light source irradiating the detector surface PD and junction capacitance C J .

5. The photoelectric conversion circuit for an omnidirectional photoelectric receiver according to claim 1, characterized in that: The pulse level output circuit adopts a hysteresis comparator circuit design, and the comparator adopts a high-speed comparator of the SGM8740 model.

6. The photoelectric conversion circuit for an omnidirectional photoelectric receiver according to claim 1, characterized in that: The reference voltage source unit is used to provide an output limit level, specifically: The reference voltage source unit provides a 3.3V limit level for the hysteresis comparator of the pulse level output circuit; when the input signal in the hysteresis comparator is within the threshold width, a pulse signal with a reference voltage of 3.3V is output; When the input signal in the hysteresis comparator exceeds the threshold width, the input signal is filtered out.

Images