Photoelectric sensing circuit and photoelectric sensor

Abstract

The present invention discloses a photoelectric sensing circuit and a photoelectric sensor. The photoelectric sensing circuit includes a light driving module, a light sampling module, a control module and a signal output module. The light sampling module includes a photodiode, a signal filtering module, a reference voltage output module and a first switch module. The control module controls the driving module to drive the laser to emit a light signal, and inputs a voltage to the reference voltage output module to make the first switch module work and then make the light sampling module output a third electrical signal, receive the third electrical signal and control the signal output module to output a signal according to the third electrical signal. The technical solution has a simple circuit structure, high performance, low noise, high reliability and the like, can be widely used in fields requiring photoelectric sensing, and can suppress external interference, greatly improving the accuracy and stability of signal acquisition.

Description

Technical Field

[0001] The present invention relates to the field of photoelectric sensing technology, and in particular to a photoelectric sensing circuit and a photoelectric sensor. Background Art

[0002] In modern industry and daily life, photodiodes, as a key device for converting optical signals into electrical signals, are widely used in many fields such as optical communications, optical sensors, medical equipment, and automatic control. The working principle of photodiodes is based on the absorption of photon energy and the generation of electron-hole pairs, thereby realizing the signal conversion from light to electricity. However, with the continuous expansion of technological applications, traditional photoelectric pulse signal acquisition circuits face many challenges. With the continuous expansion of optoelectronic application fields, the requirements for photoelectric pulse signal acquisition technology are also increasing, including the demand for higher sensitivity, wider dynamic range, lower noise, and higher data acquisition accuracy. These factors have further promoted the complexity of related circuit design, and traditional solutions can no longer meet the needs of emerging applications.

[0003] Based on this, there is an urgent need for a new photoelectric pulse signal acquisition circuit and device that can simplify circuit design and reduce manufacturing costs while ensuring high performance, so as to address the problems existing in the current technical field and promote the further development and innovation of photoelectric signal acquisition technology. Summary of the invention

[0004] The embodiments of the present invention provide a photoelectric sensing circuit and a photoelectric sensor to solve the above technical problems.

[0005] A first aspect of an embodiment of the present invention provides a photoelectric sensor circuit, including:

[0006] An optical driving module, connected to the laser, for driving the laser to emit an optical signal;

[0007] An optical sampling module comprises a photodiode, a signal filtering module, a reference voltage output module and a first switch module, wherein the anode of the photodiode and the voltage input terminal of the reference voltage output module are connected together and constitute the input terminal of the optical sampling module, the cathode of the photodiode is connected to one end of the signal filtering module, the other end of the signal filtering module is connected to the control terminal of the first switch module, the voltage output terminal of the reference voltage output module is connected to one end of the first switch module, and the other end of the first switch module is grounded, the photodiode converts the optical signal into a first electrical signal, and the signal filtering module filters the first electrical signal and outputs a second electrical signal to the first switch module;

[0008] A control module and a signal output module, wherein the control module is respectively connected to the input end of the optical driving module, the input end of the reference voltage output module, one end of the first switch module and the input end of the signal output module, and is used to control the driving module to drive the laser to emit an optical signal, and input a voltage to the reference voltage output module so that the first switch module works and the optical sampling module outputs a third electrical signal, and receives the third electrical signal and controls the signal output module to output a signal according to the third electrical signal.

[0009] Optionally, the signal filtering module includes a third transistor, an eighth capacitor, a ninth capacitor and an eleventh resistor;

[0010] The emitter of the third transistor, one end of the eighth capacitor and one end of the ninth capacitor are connected together as one end of the signal filtering module, the base of the third transistor is respectively connected to the other end of the ninth capacitor and one end of the eleventh resistor, the collector of the third transistor and the other end of the eleventh resistor are connected to the ground, and the other end of the eighth capacitor is the other end of the signal filtering module.

[0011] Optionally, the reference voltage output module includes a second capacitor, a seventh capacitor, a thirteenth capacitor, a fourteenth resistor and a fifth transistor;

[0012] One end of the second capacitor, one end of the seventh capacitor, one end of the thirteenth capacitor and the emitter of the fifth transistor are connected together as the voltage input end of the reference voltage output module, the other end of the second capacitor and the other end of the thirteenth capacitor are connected to the ground, the other end of the seventh capacitor is respectively connected to the base of the fifth transistor and one end of the fourteenth resistor, and the collector of the fifth transistor and the other end of the fourteenth resistor are connected together as the voltage output end of the reference voltage output module.

[0013] Optionally, the first switch module includes a seventh resistor and a fourth MOS tube, one end of the seventh resistor and the gate of the fourth MOS tube are connected together as the control end of the first switch module, the drain of the fourth MOS tube is one end of the first switch module, and the source of the fourth MOS tube is the other end of the first switch module.

[0014] Optionally, the optical driving module includes a sixth resistor, a ninth resistor, a nineteenth resistor, a tenth capacitor, a second transistor and a ninth transistor;

[0015] One end of the ninth resistor is the input end of the light driving module, the other end of the ninth resistor is respectively connected to the base of the second transistor and the collector of the ninth transistor, the collector of the second transistor is respectively connected to one end of the tenth capacitor and one end of the nineteenth resistor, the other end of the tenth capacitor is grounded, the other end of the nineteenth resistor receives a first voltage, the emitter of the second transistor is connected to the first end of the laser, the base of the ninth transistor is respectively connected to one end of the sixth resistor and the second end of the laser, and the emitter of the ninth transistor and the other end of the sixth resistor are commonly connected to the ground.

[0016] Optionally, the signal output module includes:

[0017] A second switch module, wherein a first end of the second switch module is an output end of the signal output module;

[0018] a signal input module, wherein a first end of the signal input module receives a first voltage, a second end of the signal input module is connected to a control end of the second switch module, a third end of the signal input module receives a control signal and controls the on or off of the second switch module according to the control signal, and a fourth end of the signal input module is grounded;

[0019] a first protection module, wherein a first end of the first protection module receives a first voltage, a second end of the first protection module is connected to a second end of the second switch module, and a third end of the first protection module is respectively connected to a control end of the second switch module, so as to turn off the second switch module when a current flowing through the second switch module exceeds a preset current value;

[0020] A second protection module, wherein a first end of the second protection module receives the first voltage, a second end of the second protection module is connected to a control end of the second switch module, and a third end of the second protection module is grounded to shut down the second switch module when the temperature exceeds a preset temperature value.

[0021] Optionally, the first protection module includes a sixteenth resistor and a sixth transistor, one end of the sixteenth resistor and the emitter of the sixth transistor are connected together as the first end of the first protection module, the other end of the sixteenth resistor and the base of the sixth transistor are connected together as the second end of the first protection module, and the collector of the sixth transistor is the third end of the first protection module;

[0022] The second switch module includes a first transistor, a ninth diode and a tenth diode, the emitter of the first transistor is the second end of the second switch module, the base of the first transistor is the control end of the second switch module, the collector of the first transistor is connected to the anode of the ninth diode, the cathode of the ninth diode and the cathode of the tenth diode are connected together as the first end of the second switch module, and the anode of the tenth diode is grounded.

[0023] Optionally, the second protection module includes a first resistor, a seventeenth resistor and an eighth transistor, one end of the seventeenth resistor and the emitter of the eighth transistor are connected together as the first end of the second protection module, the collector of the eighth transistor is the second end of the second protection module, the base of the eighth transistor is respectively connected to the other end of the seventeenth resistor and one end of the first resistor, and the other end of the first resistor is the third end of the second protection module.

[0024] Optionally, the signal input module includes a fifth resistor, a tenth resistor, an eighteenth resistor and a seventh transistor;

[0025] One end of the fifth resistor is the first end of the signal input module, the other end of the fifth resistor is respectively connected to one end of the eighteenth resistor and the collector of the seventh transistor, the other end of the eighteenth resistor is the second end of the signal input module, the base of the seventh transistor is connected to one end of the tenth resistor, the other end of the tenth resistor is the third end of the signal input module, and the emitter of the seventh transistor is the fourth end of the signal input module.

[0026] A second aspect of an embodiment of the present invention provides a photoelectric sensor, comprising: the photoelectric sensor circuit and a light emitting diode described in the first aspect.

[0027] The technical effect of the embodiment of the present invention is as follows: through the coordinated work of each module, efficient optical signal acquisition and processing are achieved, the optical drive module ensures stable emission of the laser, the optical sampling module accurately collects and processes the optical signal, and the control module effectively coordinates the work of each part and controls the output according to the collected optical signal. The entire circuit structure is simple, with the characteristics of high performance, low noise, and high reliability. It can be widely used in fields requiring photoelectric sensing, and can suppress external interference, greatly improving the accuracy and stability of signal acquisition. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0029] Figure 1 is a schematic structural diagram of a photoelectric sensor circuit provided in Embodiment 1 of the present invention;

[0030] Figure 2 is a circuit diagram of a light sampling module in a photoelectric sensing circuit provided in Embodiment 1 of the present invention;

[0031] Figure 3 This is a signal waveform diagram generated when a first photodiode D1 in a light sampling module in a photoelectric sensor circuit provided in the first embodiment of the present invention receives infrared light;

[0032] Figure 4 It is a partial circuit diagram of a light sampling module in a photoelectric sensing circuit provided by the prior art;

[0033] Figure 5 This is a partial circuit diagram of a light sampling module in a photoelectric sensor circuit provided in Embodiment 1 of the present invention;

[0034] Figure 6 yes Figure 5 The voltage amplitude waveform of the output terminal S1;

[0035] Figure 7 yes Figure 4 The voltage amplitude waveform of the output terminal S2;

[0036] Figure 8 yes Figure 4 Signal waveform diagram of output terminal S2;

[0037] Fig. 9 yes Figure 5 Signal waveform diagram of output terminal S1;

[0038] Fig.10 yes Figure 5 AC equivalent circuit diagram;

[0039] Fig.11 yes Figure 5 The DC equivalent circuit diagram of

[0040] Fig.12 yes Figure 2 The characteristic curve diagram of the fourth MOS tube Q4;

[0041] Fig.13 yes Figure 2The signal waveform diagram of the G terminal of the fourth MOS tube Q4;

[0042] Fig.14 yes Figure 2 The ADC sampling signal waveform at the other end of the thirteenth resistor R13;

[0043] Fig.15 is a circuit diagram of a light driving module in a photoelectric sensor circuit provided in Embodiment 1 of the present invention;

[0044] Fig.16 It is a structural schematic diagram of a signal output module in a photoelectric sensor circuit provided in Embodiment 1 of the present invention;

[0045] Fig.17 is a circuit diagram of a signal output module in a photoelectric sensor circuit provided in Embodiment 1 of the present invention;

[0046] Fig.18 is a circuit diagram of a power supply module in a photoelectric sensor circuit provided in Embodiment 1 of the present invention;

[0047] Fig.19 is a circuit diagram of a single chip microcomputer in a control module in a photoelectric sensor circuit provided in Embodiment 1 of the present invention;

[0048] Fig. 20 It is a circuit diagram of a burning port in a control module in a photoelectric sensor circuit provided in Embodiment 1 of the present invention;

[0049] In the figure: 101, optical drive module; 102, optical sampling module; 103, control module; 104, signal output module; 121, photodiode; 122, signal filtering module; 123, reference voltage output module; 124, first switch module; 141, second switch module; 142, signal input module; 143, first protection module; 144, second protection module; 20, laser. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] It should be understood that the present invention can be implemented in different forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, providing these embodiments will make the disclosure thorough and complete and fully convey the scope of the present invention to those skilled in the art. In the accompanying drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity. The same reference numerals throughout represent the same elements.

[0052] It should be understood that when an element or layer is referred to as being "on, adjacent to, connected to or coupled to other elements or layers, it may be directly on, adjacent to, connected to or coupled to other elements or layers, or there may be intervening elements or layers. In contrast, when an element is referred to as being "directly on, directly adjacent to, directly connected to or directly coupled to other elements or layers, there may be no intervening elements or layers. It should be understood that, although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present invention, the first element, component, region, layer or part discussed below may be represented as a second element, component, region, layer or part.

[0053] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present invention. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0054] In order to fully understand the present invention, detailed structures and steps will be presented in the following description to illustrate the technical solutions proposed by the present invention. The preferred embodiments of the present invention are described in detail below, but in addition to these detailed descriptions, the present invention may also have other implementations.

[0055] Embodiment 1

[0056] This embodiment 1 provides a photoelectric sensor circuit, such as Figure 1 As shown, including:

[0057] The optical driving module 101 is connected to the laser 20 and is used to drive the laser 20 to emit an optical signal;

[0058] The optical sampling module 102 includes a photodiode 121, a signal filtering module 122, a reference voltage output module 123 and a first switch module 124. The anode of the photodiode 121 is connected to the voltage input end of the reference voltage output module 123, the cathode of the photodiode 121 is connected to one end of the signal filtering module 122, the other end of the signal filtering module 122 is connected to the control end of the first switch module 124, the voltage output end of the reference voltage output module 123 is connected to one end of the first switch module 124, and the other end of the first switch module 124 is grounded. The photodiode 121 converts the optical signal into a first electrical signal, and the signal filtering module 122 filters the first electrical signal and outputs a second electrical signal to the first switch module 124.

[0059] The control module 103 and the signal output module 104 are respectively connected to the input end of the light driving module 101, the input end of the reference voltage output module 123, one end of the first switch module 124 and the signal output module 104, and are used to control the light driving module 101 to drive the laser 20 to emit a light signal, and input voltage to the reference voltage output module 123 to make the first switch module 124 work so that the light sampling module 102 outputs a third electrical signal, and receive the third electrical signal and control the signal output module 104 to output a signal according to the third electrical signal.

[0060] Among them, the optical drive module 101 is used to drive the laser 20 to emit an optical signal. After receiving the control signal from the control module 103, the optical drive module 101 provides power or driving current to the laser 20, so that the laser 20 emits a predetermined optical signal. The emission of the optical signal can be a pulse or a continuous wave optical signal, depending on the application scenario and control requirements. The optical sampling module 102 receives the optical signal through the photodiode 121 and converts it into an electrical signal, then filters and processes the electrical signal, and finally outputs it to the control module 103. The photodiode 121 receives the optical signal from the laser 20 and converts the optical signal into a first electrical signal. The anode of the photodiode 121 is connected to the voltage input terminal of the reference voltage output module 123 to ensure that it works under controlled voltage conditions and provide a stable sampling environment. The first electrical signal passes through the signal filtering module 122 to filter out unnecessary noise or interference components to obtain a second electrical signal. The filtered second electrical signal controls the working state of the first switch module 124 and outputs a third electrical signal to the control module 103. The control module 103 coordinates the work of the entire circuit, including controlling the work of the optical drive module 101 and the optical sampling module 102, processing the sampling signal, and controlling the work of the signal output module 104. The control module 103 first sends a control signal to the optical drive module 101 to enable the laser 20 to emit an optical signal. At the same time, the control module 103 provides an input voltage for the reference voltage output module 123 of the optical sampling module 102 to ensure that the optical sampling module 102 works normally. The output signal (third electrical signal) of the optical sampling module 102 is sent back to the control module 103, and the control module 103 analyzes and processes the received third electrical signal. According to the processing result, the control module 103 controls the signal output module 104 to output the final signal for subsequent applications. According to the instructions of the control module 103, the signal output module 104 outputs the processed signal to the external system as the final output of the entire photoelectric sensing system. After receiving the control signal transmitted by the control module 103, the signal output module 104 outputs the corresponding electrical signal or state signal according to the requirements of the control module 103 for use by the external system. This output signal may be used for different purposes such as display, control or feedback.

[0061] The technical effect of the technical solution provided in the first embodiment is that the photoelectric sensing circuit realizes efficient light signal acquisition and processing through the coordinated work of various modules, the optical drive module ensures the stable emission of the laser, the optical sampling module accurately collects and processes the light signal, and the control module effectively coordinates the work of various parts and controls the output according to the collected light signal. The entire circuit structure is simple, with the characteristics of high performance, low noise, and high reliability. It can be widely used in fields requiring photoelectric sensing, and can suppress external interference, greatly improving the accuracy and stability of signal acquisition.

[0062] As an example, Figure 2 As shown, it is a specific circuit diagram of the optical sampling module 102, the signal filtering module 122 includes a third triode Q3, an eighth capacitor C8, a ninth capacitor C9 and an eleventh resistor R11; the emitter of the third triode Q3, one end of the eighth capacitor C8 and one end of the ninth capacitor C9 are connected together as one end of the signal filtering module 122, the base of the third triode Q3 is respectively connected to the other end of the ninth capacitor C9 and one end of the eleventh resistor R11, the collector of the third triode Q3 and the other end of the eleventh resistor R11 are connected to the ground, and the other end of the eighth capacitor C8 is the other end of the signal filtering module 122.

[0063] The reference voltage output module 123 includes a second capacitor C2, a seventh capacitor C7, a thirteenth capacitor C13, a fourteenth resistor R14 and a fifth transistor Q5; one end of the second capacitor C2, one end of the seventh capacitor C7, one end of the thirteenth capacitor C13 and the emitter of the fifth transistor Q5 are connected together as a voltage input end of the reference voltage output module 123, the other end of the second capacitor C2 and the other end of the thirteenth capacitor C13 are connected to the ground, the other end of the seventh capacitor C7 is respectively connected to the base of the fifth transistor Q5 and one end of the fourteenth resistor R14, and the collector of the fifth transistor Q5 and the other end of the fourteenth resistor R14 are connected together as a voltage output end of the reference voltage output module 123.

[0064] The first switch module 124 includes a seventh resistor R7 and a fourth MOS transistor Q4. One end of the seventh resistor R7 and the gate of the fourth MOS transistor Q4 are connected together as a control end of the first switch module 124. The other end of the seventh resistor R7 is grounded. The drain of the fourth MOS transistor Q4 is one end of the first switch module 124. The source of the fourth MOS transistor Q4 is the other end of the first switch module 124.

[0065] The optical sampling module 102 also includes a fifteenth resistor R15 and a thirteenth resistor R13, one end of the fifteenth resistor R15 is the input end of the optical sampling module 102, the other end of the fifteenth resistor R15 is connected to one end of the thirteenth capacitor C13, one end of the thirteenth resistor R13 is connected to one end of the fourteenth resistor R14, and the other end of the thirteenth resistor R13 is the output end of the optical sampling module 102.

[0066] Among them, the cooperation structure of the ninth capacitor C9 and the eleventh resistor R11 is the prototype of the differential circuit. Because the front end of the ninth capacitor C9 is the first photodiode D1 outputting the pulse signal, the ninth capacitor C9 and the eleventh resistor R11 cooperate to form a high-pass filter, such as Figure 3 As shown, the function is to maintain and improve the waveform of the pulse signal output by the first photodiode D1 when passing through the base of the third transistor Q3. Figure 4As shown, it is a design in the prior art, the third photodiode D3 directly outputs a pulse signal. If the third photodiode D3 is equivalent to a resistor Rd3, when natural light shines on the third photodiode D3, the S2 voltage VS2≈[R21 / (R21+Rd3)]×VCC. Figure 5 As shown, compared with the design of this technical solution, the first photodiode D1 is equivalent to a resistor Rd2, and the S1 voltage VS1≈[R11 / (R11×β+Rd2)]×VCC. At this time, the third transistor Q3 is in the amplification working range, and its amplification factor is set to β times (here the β coefficient of the transistor is selected to be greater than 100, and the amplification factor varies according to the actual working conditions). Under the same natural light, according to the above S1 and S2 value formulas, the voltage interference (S1 value) generated by this design is smaller, and the voltage interference (S2 value) generated by the existing design is larger, that is, the S2 signal is more likely to be saturated. When the external natural light is slightly stronger, the signal that can be collected by the existing technical solution is saturated (the value of S2 is close to the maximum value VCC), and the subsequent circuit cannot collect the signal normally. On the other hand, this design produces less interference under natural light. Under strong infrared light, the signal has more floating space and will not be saturated too quickly. At this time, when the red light pulse from the transmitting end shines on the first photodiode D1 and the third photodiode D3 at the same time, the voltage amplitude waveforms of S1 and S2 on the oscilloscope are as follows: Figure 6 and Figure 7 As shown: Under the same natural light of about 2000Lux, VCC supplies 5V, Figure 6 The voltage amplitude of S1 in is only 0.514V. Figure 7 The voltage of S2 in the circuit has reached 4.29V. The signal waveforms of S1 and S2 on the oscilloscope are as follows: Figure 8 and Fig. 9 As shown: It can be clearly found that Figure 8 As shown in Figure 2, the S2 signal is approaching saturation and no obvious signal can be seen. Fig. 9 As shown, the signal of S1 is complete and observable, and the ambient light has almost no effect. When the modulated light signal shines on the first photodiode D1, an AC signal is generated at S1. According to the equivalent resistance calculation formula of the capacitor: ZC9≈1 / 2Πfc, the impedance of the ninth capacitor C9 can be less than 10Ω or even less than 1Ω at high frequencies. This conclusion can also be drawn from the capacitor equivalent impedance diagram provided by the actual manufacturer. If a suitable capacitor C9 is selected, the value of its equivalent resistance ZC9 will be very small. In the case of an AC path (the photodiode receives modulated infrared light), the voltage across capacitor C9 VC9=((VCC-VD1)×ZC9) / (ZC9+R11), because ZC9 is less than 10Ω, when R11 is selected as 1M, VCC is less than 100V, the voltage across capacitor C9 VC9<0.1V, the third transistor Q3 is not conducting, and the circuit is equivalent to Fig.10As shown. The resistance selected by R11 is very large. When R11=1MΩ, the AC line impedance is set to RAC. Then RAC≈R20=1MΩ. In the case of a DC path (normal ambient light), the ninth capacitor C9 is equivalent to an open circuit, and the circuit is equivalent to Fig.11 As shown. Fig.11 , let Vbe be the on-state voltage of the third transistor Q3, set i as the current flowing through the eleventh resistor R11, then i≈(VCC-Vbe) / R11, using the limit method, the equivalent impedance of the line in DC is set to RDC, then RDC≈VCC / (i+βi); when VCC is large and Vbe is very small, then i≈VCC / R20; then the DC equivalent impedance RDC≈R20 / (β+1) can be calculated, assuming that the β coefficient of the transistor is 100, when R20 is 1MΩ, RDC≈10KΩ.

[0067] Combining the above two situations, when the AC impedance RAC≈1MΩ, the DC impedance RDC≈10KΩ.

[0068] That is to say, the circuit's AC impedance RAC≈β times the DC impedance RDC.

[0069] After obtaining a large amount of data through practical tests, combined with data analysis and summary, we finally got a conclusion: the circuit in this implementation is different from the existing design circuit in that the circuit in this implementation has a large impedance when passing AC and a small impedance when passing DC, realizing photoelectric signal collection with little interference in ambient light, and when receiving infrared light (light pulses after high-frequency modulation) signals, the signal collection is not distorted and is complete and intuitive.

[0070] It should be noted that, in addition to the above-mentioned structure, the signal filtering module 122 includes but is not limited to the following structures: RC low-pass filter, LC filter, active filter, Butterworth filter, band-pass filter, etc.

[0071] It should be noted that, in addition to the above structure, the reference voltage output module 123 includes but is not limited to the following structures: Zener diode reference voltage, shunt regulator, series regulator, current source reference voltage circuit, low voltage dropout regulator, etc.

[0072] Further integration Figure 2 As shown in the circuit diagram, the designed signal path requires the fourth MOS tube Q4 to be turned on. Part of the characteristic curve of the fourth MOS tube Q4 is as follows Fig.12 As shown, it is the drain current I D and the gate-source voltage V GSThe relationship curve between them, where the drain-source voltage VDS is 2V and the ambient temperature Ta is 25 degrees Celsius. According to the characteristics of the MOS tube, when the MOS tube is turned on, the G level needs to receive a low level to turn off the MOS tube again. Another function of the third transistor Q3 is that when the pulse of the first photodiode D1 is generated, the base of the third transistor Q3 has a high level of a certain frequency, which enables the third transistor Q3 to be turned on to the ground, that is, a low level of a certain frequency is given to the G pole of the fourth MOS tube Q4, enabling the fourth MOS tube Q4 to be disconnected. The eighth capacitor C8 and the seventh resistor R7 are also high-pass filters, but this position is relatively special. According to the calculation formula of capacitive reactance, selecting a suitable capacitance value will make the amplitude of the waveform change when the pulse signal of the first photodiode D1 reaches the G level of the fourth MOS tube Q4, and the waveform will also change in curvature due to the capacitor charging and discharging process. The ideal waveform collected here at the G level of the fourth MOS tube Q4 is as follows. Fig.13 As shown. DAC is a high level generated by the control module 103. The fifteenth resistor R15, the thirteenth capacitor C13, and the second capacitor C2 cooperate to make the DAC level more stable. When the first photodiode D1 receives infrared light to generate a pulse signal, the seventh capacitor C7, the fourteenth resistor R14 and the fifth transistor Q5 cooperate to provide a reference high level to the D level of the fourth MOS tube Q4. At the same time, the seventh capacitor C7 can also prevent the pulse signal from passing through the first photodiode D1 and generating an interference pulse signal. The fourteenth resistor R14 is used to limit the current when an interference pulse passes through the seventh capacitor C7 to prevent the back-end acquisition signal from being affected. The back end of the thirteenth resistor R13 is the ADC acquisition end of the control module 103. The function of the thirteenth resistor R13 is to limit the current. When the ADC is collecting, it indirectly protects the control module 103. In combination with the above, when the first photodiode D1 receives infrared light, the G level of the fourth MOS tube Q4 receives a signal pulse such as Fig.13 As shown, the first photodiode D has a stable reference high level, and the fourth MOS tube Q4 switches with the frequency of the pulse generated by the first photodiode D1. When the ADC collects, there is the following Fig.14 The control module 103 collects the minimum value of the continuous analog signal through the ADC, and then performs numerical conversion and outputs it through the signal output module 104.

[0073] As an implementation method, Fig.15As shown, the light driving module 101 includes a sixth resistor R6, a ninth resistor R9, a nineteenth resistor R19, a tenth capacitor C10, a second triode Q2 and a ninth triode Q9; one end of the ninth resistor R9 is the input end of the light driving module 101, the other end of the ninth resistor R9 is respectively connected to the base of the second triode Q2 and the collector of the ninth triode Q9, the collector of the second triode Q2 is respectively connected to one end of the tenth capacitor C10 and one end of the nineteenth resistor R19, the other end of the tenth capacitor C10 is grounded, the other end of the nineteenth resistor R19 receives the first voltage VCC1, the emitter of the second triode Q2 is connected to the first end of the laser 20, the base of the ninth triode Q9 is respectively connected to one end of the sixth resistor R6 and the second end of the laser 20, and the emitter of the ninth triode Q9 and the other end of the sixth resistor R6 are commonly grounded.

[0074] Among them, the first voltage VCC1 is provided by the power supply module, the nineteenth resistor R19 and the tenth capacitor C10 cooperate to form a low-pass filter, and provide a stable power supply to the laser LASER1, the sixth resistor R6 is a current-limiting resistor of the current path, and the ninth resistor R9 is a current-limiting resistor for driving the second triode Q2 in the control module input laser LASER1, and the second triode Q2 is used as a switch of the laser LASER1. The function of the ninth triode Q9 is that when the current flows through the laser LASER1, the voltage across the sixth resistor R6 reaches the conduction condition of the ninth triode Q9, so that the collector of the ninth triode Q9 is pulled down, and the laser LASER1 is turned off, thereby protecting the laser LASER1 in the case of overcurrent.

[0075] The technical effect of this implementation is: a stable power supply is provided through a low-pass filter, a current-limiting resistor ensures a safe current range, and an overcurrent protection mechanism and switch control are combined to ensure that the laser LASER1 can operate stably and safely under various working conditions, avoiding damage or misoperation caused by overcurrent, unstable power supply and other problems, which not only improves the reliability of the circuit, but also extends the service life of the laser.

[0076] It should be noted that, in addition to the above structure, the optical drive module 101 also includes but is not limited to the following structures:

[0077] 1. Constant current drive circuit: Use an operational amplifier and MOSFET or BJT to maintain a constant current output, and the laser is connected to the output end of the constant current circuit.

[0078] 2. The PWM (pulse width modulation) control circuit drives the MOSFET or BJT through a PWM signal source (usually an MCU) to control the output power of the laser by changing the duty cycle.

[0079] 3. Linear drive circuit: It is composed of a linear voltage regulator or an integrated current stabilization chip, which directly drives the laser to work.

[0080] 4. Based on integrated laser driver IC: Using dedicated laser driver integrated circuits, these ICs usually integrate constant current drive, protection functions and feedback control.

[0081] As an implementation method, Fig.16 As shown, the signal output module 104 includes:

[0082] A second switch module 141, wherein a first end of the second switch module 141 is an output end of the signal output module 104;

[0083] A signal input module 142, wherein a first terminal of the signal input module 142 receives a first voltage VCC1, a second terminal of the signal input module 142 is connected to a control terminal of the second switch module 141, a third terminal of the signal input module 142 receives a control signal, and controls the on or off of the second switch module 141 according to the control signal, and a fourth terminal of the signal input module 142 is grounded;

[0084] A first protection module 143, wherein a first end of the first protection module 143 receives a first voltage, a second end of the first protection module 143 is connected to a second end of the second switch module 141, and a third end of the first protection module 143 is respectively connected to a control end of the second switch module 141, so as to turn off the second switch module 141 when a current flowing through the second switch module 141 exceeds a preset current value;

[0085] The second protection module 144, the first end of the second protection module 144 receives the first voltage, the second end of the second protection module 144 is connected to the control end of the second switch module 141, and the third end of the second protection module 144 is grounded to turn off the second switch module 141 when the temperature exceeds the preset temperature value.

[0086] Among them, the second switch module 141 is the core switch element of the signal output module 104, and controls the output of the signal. When the control signal output by the signal input module 142 turns on the second switch module 141, the signal is transmitted from the input end to the output end to realize the output of the signal; when the control signal turns off the second switch module 141, the signal output is cut off. The signal input module 142 receives an external control signal and controls the working state (on or off) of the second switch module 141 according to the signal. The first end of the signal input module 142 receives a first voltage, and the third end receives an external input control signal. According to the input control signal, the signal input module 142 adjusts its output to control the on or off of the second switch module 141. Usually, when the control signal is high, the second switch module 141 is turned on; when the control signal is low, the second switch module 141 is turned off. The first protection module 143 mainly provides overcurrent protection. When the current flowing through the second switch module 141 exceeds a preset value, the first protection module 143 will turn off the second switch module 141 to prevent overcurrent from damaging the circuit. When the current flowing through the second switch module 141 exceeds the preset value, the first protection module 143 detects the abnormal current and sends a shutdown signal, shutting down the second switch module 141 and preventing further signal output, thereby protecting the downstream circuit. The second protection module 144 provides over-temperature protection. When the temperature inside the module exceeds the preset value, the second protection module 144 shuts down the second switch module 141 to prevent malfunctions caused by overheating. When the system temperature rises and exceeds the set threshold, the second protection module 144 detects the temperature abnormality and controls the second switch module 141 to shut down to prevent the circuit from overheating and causing component damage or malfunction.

[0087] The technical effect of this implementation is that the signal output module realizes flexible signal output control through precise design, and has dual protection functions (overcurrent and overtemperature protection). The signal input module accurately adjusts the signal output according to the control signal, while the first protection module and the second protection module provide current and temperature protection respectively, ensuring that the system operates safely and stably in a complex working environment. Through the coordinated work of these modules, the system can respond quickly and automatically shut down the output when encountering abnormal situations, avoiding damage to circuits and equipment, and improving the safety and reliability of the system.

[0088] As an example, Fig.17 As shown, the first protection module 143 includes a sixteenth resistor R16 and a sixth transistor Q6, one end of the sixteenth resistor R16 and the emitter of the sixth transistor Q6 are connected together as the first end of the first protection module 143, the other end of the sixteenth resistor R16 and the base of the sixth transistor Q6 are connected together as the second end of the first protection module 143, and the collector of the sixth transistor Q6 is the third end of the first protection module 143.

[0089] The second switch module 141 includes a first transistor Q1, a ninth diode D9 and a tenth diode D10, the emitter of the first transistor Q1 is the second end of the second switch module 141, the base of the first transistor Q1 is the control end of the second switch module 141, the collector of the first transistor Q1 is connected to the anode of the ninth diode D9, the cathode of the ninth diode D9 and the cathode of the tenth diode D10 are connected together as the first end of the second switch module 141, and the anode of the tenth diode D10 is grounded.

[0090] The second protection module 144 includes a first resistor R1, a seventeenth resistor R17 and an eighth transistor Q8, one end of the seventeenth resistor R17 and the emitter of the eighth transistor Q8 are connected together as the first end of the second protection module 144, the collector of the eighth transistor Q8 is the second end of the second protection module 144, the base of the eighth transistor Q8 is respectively connected to the other end of the seventeenth resistor R17 and one end of the first resistor R1, and the other end of the first resistor R1 is the third end of the second protection module 144.

[0091] The signal input module 142 includes a fifth resistor R5, a tenth resistor R10, an eighteenth resistor R18 and a seventh transistor Q7; one end of the fifth resistor R5 is the first end of the signal input module 142, the other end of the fifth resistor R5 is respectively connected to one end of the eighteenth resistor R18 and the collector of the seventh transistor Q7, the other end of the eighteenth resistor R18 is the second end of the signal input module 142, the base of the seventh transistor Q7 is connected to one end of the tenth resistor R10, the other end of the tenth resistor R10 is the third end of the signal input module 142, and the emitter of the seventh transistor Q7 is the fourth end of the signal input module 142.

[0092] Among them, the signal output module 104 is a PNP transistor signal output circuit with both overcurrent protection and overtemperature protection. The function of the sixteenth resistor R16 is to limit the current. For example, if the signal output is required to carry 100mA, when the output is extremely large and exceeds 100mA, the sixth transistor Q6 reaches the conduction condition and turns on, and VCC1 passes through the sixth transistor Q6 to the base of the first transistor Q1, cutting off the signal output and realizing overcurrent protection. The seventeenth resistor R17 cooperates with the first resistor R1 to form a simple voltage divider circuit. The first resistor R1 is a thermistor. The resistance of the first resistor R1 is very large at room temperature. When the temperature is too high, the resistance of the first resistor R1 will change. When the temperature is too high to the preset value, the configured seventeenth resistor R17 and the first resistor R1 divide the voltage at the base of the eighth transistor Q8 to reach the conduction condition of the eighth transistor Q8, enabling the eighth transistor Q8 to be turned on, and VCC1 passes through the eighth transistor Q8 to the base of the first transistor Q1, so the signal output is cut off to achieve over-temperature protection. The eighteenth resistor R18, the fifth resistor R5, and the tenth resistor R10 cooperate with the seventh transistor Q7 to form a switch for the first transistor Q1 to enable the signal output. PUTOUT is the output control signal of the control module 103 to the seventh transistor Q7, and SIGNAL-PNP is the output signal.

[0093] The technical effect of this implementation is that through the triple protection and control mechanism of current limiting, over-temperature and control signal, the stable control of the signal output of the PNP transistor is achieved. The over-current protection avoids circuit damage caused by excessive current, and the over-temperature protection effectively prevents failures under high temperature conditions. In addition, the signal output control circuit ensures that the system can respond accurately when receiving external control signals, has good safety, stability and durability, and is suitable for various scenarios that require stable signal output and protection functions.

[0094] As an implementation method, Fig.18 As shown, the power supply module includes a fuse R4, a Schottky diode D7, an electrostatic protection diode D8, a third capacitor C3, a fourth capacitor C4, a sixth capacitor C6, a first inductor L1 and a buck chip U2. One end of the fuse R4 receives the input voltage VIN, and the other end of the fuse R4 is respectively connected to the anode of the Schottky diode D7 and the cathode of the electrostatic protection diode D8. The cathode of the Schottky diode D7, one end of the third capacitor C3 and one end of the first inductor L1 are connected together to receive the first voltage VCC1. The other end of the first inductor L1 is respectively connected to one end of the sixth capacitor C6 and the pin 3 of the buck chip U2. The pin 1 of the buck chip U2 and one end of the fourth capacitor C4 are connected together to output the second voltage VCC2. The anode of the electrostatic protection diode D8, the other end of the third capacitor C3, the other end of the fourth capacitor C4, the other end of the sixth capacitor C6 and the pin 2 of the buck chip U2 are all grounded.

[0095] Among them, the fuse R4, together with the electrostatic protection diode D8 and the Schottky diode D7, is a protection device for the power input. The third capacitor C3 buffers the jitter of the input voltage and reduces noise. The first inductor L1 and the sixth capacitor C6 form an LC circuit to eliminate ripples in the current waveform. The buck chip U2 powers the control module 103 after stepping down the voltage.

[0096] As an implementation method, Fig.19 and Fig. 20 As shown, the control module 103 circuit is mainly composed of the burning port P1 and the single-chip microcomputer U3. The pin 2 of the single-chip microcomputer U3 is connected to the indicator light D4 through the second resistor R2, and the pin 3 of the single-chip microcomputer U3 is connected to the indicator light D5 through the third resistor R3. The indicator lights D4 and D5 are used for signal output indication.

[0097] Embodiment 2

[0098] The second embodiment provides a photoelectric sensor, including the photoelectric sensor circuit and the laser provided in the first embodiment.

[0099] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. A photoelectric sensor circuit, characterized in that: include: An optical driving module, connected to the laser, for driving the laser to emit an optical signal; An optical sampling module comprises a photodiode, a signal filtering module, a reference voltage output module and a first switch module, wherein the anode of the photodiode and the voltage input terminal of the reference voltage output module are connected together and constitute the input terminal of the optical sampling module, the cathode of the photodiode is connected to one end of the signal filtering module, the other end of the signal filtering module is connected to the control terminal of the first switch module, the voltage output terminal of the reference voltage output module is connected to one end of the first switch module, and the other end of the first switch module is grounded, the photodiode converts the optical signal into a first electrical signal, and the signal filtering module filters the first electrical signal and outputs a second electrical signal to the first switch module; A control module and a signal output module, wherein the control module is respectively connected to the input end of the optical driving module, the input end of the reference voltage output module, one end of the first switch module and the input end of the signal output module, and is used to control the driving module to drive the laser to emit an optical signal, and input a voltage to the reference voltage output module so that the first switch module works and the optical sampling module outputs a third electrical signal, and receives the third electrical signal and controls the signal output module to output a signal according to the third electrical signal; The signal output module comprises: A second switch module, wherein a first end of the second switch module is an output end of the signal output module; a signal input module, wherein a first end of the signal input module receives a first voltage, a second end of the signal input module is connected to a control end of the second switch module, a third end of the signal input module receives a control signal and controls the on or off of the second switch module according to the control signal, and a fourth end of the signal input module is grounded; a first protection module, wherein a first end of the first protection module receives a first voltage, a second end of the first protection module is connected to a second end of the second switch module, and a third end of the first protection module is respectively connected to a control end of the second switch module, so as to turn off the second switch module when a current flowing through the second switch module exceeds a preset current value; A second protection module, wherein a first end of the second protection module receives the first voltage, a second end of the second protection module is connected to a control end of the second switch module, and a third end of the second protection module is grounded to shut down the second switch module when the temperature exceeds a preset temperature value.

2. The photoelectric sensor circuit according to claim 1, characterized in that: The signal filtering module includes a third transistor, an eighth capacitor, a ninth capacitor and an eleventh resistor; The emitter of the third transistor, one end of the eighth capacitor and one end of the ninth capacitor are connected together as one end of the signal filtering module, the base of the third transistor is respectively connected to the other end of the ninth capacitor and one end of the eleventh resistor, the collector of the third transistor and the other end of the eleventh resistor are connected to the ground, and the other end of the eighth capacitor is the other end of the signal filtering module.

3. The photoelectric sensor circuit according to claim 1, characterized in that: The reference voltage output module includes a second capacitor, a seventh capacitor, a thirteenth capacitor, a fourteenth resistor and a fifth transistor; One end of the second capacitor, one end of the seventh capacitor, one end of the thirteenth capacitor and the emitter of the fifth transistor are connected together as the voltage input end of the reference voltage output module, the other end of the second capacitor and the other end of the thirteenth capacitor are connected to the ground, the other end of the seventh capacitor is respectively connected to the base of the fifth transistor and one end of the fourteenth resistor, and the collector of the fifth transistor and the other end of the fourteenth resistor are connected together as the voltage output end of the reference voltage output module.

4. The photoelectric sensor circuit according to claim 1, characterized in that: The first switch module includes a seventh resistor and a fourth MOS tube, one end of the seventh resistor and the gate of the fourth MOS tube are connected together as the control end of the first switch module, the drain of the fourth MOS tube is one end of the first switch module, and the source of the fourth MOS tube is the other end of the first switch module.

5. The photoelectric sensor circuit according to claim 1, characterized in that: The light driving module includes a sixth resistor, a ninth resistor, a nineteenth resistor, a tenth capacitor, a second transistor and a ninth transistor; One end of the ninth resistor is the input end of the light driving module, the other end of the ninth resistor is respectively connected to the base of the second transistor and the collector of the ninth transistor, the collector of the second transistor is respectively connected to one end of the tenth capacitor and one end of the nineteenth resistor, the other end of the tenth capacitor is grounded, the other end of the nineteenth resistor receives a first voltage, the emitter of the second transistor is connected to the first end of the laser, the base of the ninth transistor is respectively connected to one end of the sixth resistor and the second end of the laser, and the emitter of the ninth transistor and the other end of the sixth resistor are commonly connected to the ground.

6. The photoelectric sensor circuit according to claim 1, characterized in that: The first protection module includes a sixteenth resistor and a sixth transistor, one end of the sixteenth resistor and the emitter of the sixth transistor are connected together as the first end of the first protection module, the other end of the sixteenth resistor and the base of the sixth transistor are connected together as the second end of the first protection module, and the collector of the sixth transistor is the third end of the first protection module; The second switch module includes a first transistor, a ninth diode and a tenth diode, the emitter of the first transistor is the second end of the second switch module, the base of the first transistor is the control end of the second switch module, the collector of the first transistor is connected to the anode of the ninth diode, the cathode of the ninth diode and the cathode of the tenth diode are connected together as the first end of the second switch module, and the anode of the tenth diode is grounded.

7. The photoelectric sensor circuit according to claim 1, characterized in that: The second protection module includes a first resistor, a seventeenth resistor and an eighth transistor, one end of the seventeenth resistor and the emitter of the eighth transistor are connected together as the first end of the second protection module, the collector of the eighth transistor is the second end of the second protection module, the base of the eighth transistor is respectively connected to the other end of the seventeenth resistor and one end of the first resistor, and the other end of the first resistor is the third end of the second protection module.

8. The photoelectric sensor circuit according to claim 1, characterized in that: The signal input module includes a fifth resistor, a tenth resistor, an eighteenth resistor and a seventh transistor; One end of the fifth resistor is the first end of the signal input module, the other end of the fifth resistor is respectively connected to one end of the eighteenth resistor and the collector of the seventh transistor, the other end of the eighteenth resistor is the second end of the signal input module, the base of the seventh transistor is connected to one end of the tenth resistor, the other end of the tenth resistor is the third end of the signal input module, and the emitter of the seventh transistor is the fourth end of the signal input module.

9. A photoelectric sensor, characterized in that: include: The photoelectric sensor circuit and laser according to any one of claims 1 to 8.

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