An infrared emitting circuit

Abstract

This invention discloses an infrared emitting circuit, relating to the field of sensors, comprising: an infrared emitting circuit emitting infrared signals to an infrared receiving circuit; an infrared receiving circuit including multiple infrared receiving tubes; the infrared emitting circuit including a temperature compensation circuit and infrared emitting tubes; the temperature compensation circuit is used to offset the increased heat dissipation current of the infrared emitting circuit at high temperatures, ensuring that the emission power of the infrared emitting tubes is consistent at high temperatures and at room temperature; the infrared emitting tubes are used to emit infrared signals to the infrared receiving circuit, so that the infrared receiving tubes on the infrared receiving circuit respond to the infrared signals. This invention can realize the monitoring of displacement, and its temperature compensation circuit not only increases the reverse leakage current with increasing temperature, which can eliminate the influence of high temperature on the infrared emitting tubes and increase the measurement accuracy at high temperatures, but also can selectively supply power, ensuring that the circuit operates in intermittent mode, enabling the overall circuit structure to perform displacement detection in harsh environments.

Description

Technical Field

[0001] This invention relates to the field of sensors, and more particularly to an infrared emitting circuit. Background Technology

[0002] With the continuous development of technology, there are more and more types of displacement detection sensors. Displacement detection sensors can convert mechanical force into electrical signals through potentiometer elements, and finally output specific values ​​after internal structure calculation, so as to realize displacement detection.

[0003] Existing displacement detection sensors only consider operation in normal environments during circuit design, neglecting applications in harsh environments, such as inside urban underground heating pipe wells. As cities develop and heating equipment becomes more sophisticated, urban underground heating pipes require full-pipe maintenance. The pipes contain high-temperature hot water or steam, and the alternating hot and cold temperatures cause horizontal thermal expansion and contraction. When this expansion exceeds a critical value, pipe damage, bursts, leaks, or other safety hazards may occur. Therefore, reliable equipment is needed to monitor pipe deformation and displacement in real time.

[0004] Since the internal temperature of underground heating pipes ranges from -20℃ to +120℃, this affects the measurement accuracy of monitoring equipment. However, there is currently no effective method to improve the measurement accuracy of equipment in harsh environments. Summary of the Invention

[0005] This invention provides an infrared emitting circuit to solve the technical problem of low measurement accuracy in harsh environments.

[0006] This invention provides the following technical solution: an infrared transmitting circuit for transmitting infrared signals to an infrared receiving circuit; the infrared receiving circuit includes multiple infrared receiving tubes;

[0007] The infrared emitting circuit includes a temperature compensation circuit and an infrared emitting tube;

[0008] The input terminal of the temperature compensation circuit is used to connect to the power supply, and the output terminal is connected to the infrared emitting tube. The temperature compensation circuit is used to compensate for the increased heat dissipation current of the infrared emitting circuit at high temperatures, ensuring that the emission power is consistent at high temperatures and at room temperature.

[0009] An infrared emitting diode is used to transmit infrared signals to an infrared receiving circuit, so that the infrared receiving diode on the infrared receiving circuit can respond to the infrared signal.

[0010] In one possible implementation, the temperature compensation circuit includes a resistor and a diode, wherein the resistor and the diode are connected in parallel.

[0011] The cathode of the diode forms the input terminal of the temperature compensation circuit, and the anode of the diode forms the output terminal of the temperature compensation circuit.

[0012] In one possible implementation, the infrared emitting circuit also includes a main control circuit and a power supply circuit;

[0013] The power supply circuit is connected in series between the temperature compensation circuit and the power supply.

[0014] The main control circuit and the power supply circuit are connected;

[0015] The main control circuit is used to send a power supply command to the power supply circuit when it receives a working signal; the working signal is the working command issued by the host computer; the power supply command is used to instruct the power supply circuit to be turned on so that the power supply can provide power to the temperature compensation circuit.

[0016] The main control circuit is also used to send a power-off command to the power supply circuit when the work completion signal is received; the work completion signal is the work completion command issued by the host computer after receiving the displacement amount uploaded by the main control circuit; the power-off command is used to instruct the power supply circuit to be turned off so that the power supply to the temperature compensation circuit is de-energized.

[0017] In one possible implementation, the power supply circuit includes a linear regulator U1, a first capacitor C2, a second capacitor C3, a first resistor R4, a second resistor R5, a third resistor R6, a MOSFET Q4, and a bidirectional transient suppressor diode D101.

[0018] The input terminal of the linear regulator U1 is the input terminal of the power supply circuit, and the output terminal of the linear regulator U1 is the output terminal of the power supply circuit. The output terminal of the linear regulator U1 includes pins 1, 2, 3, and 4. Pin 1 is grounded, pins 2 and 4 are connected to the input voltage, and pin 3 is connected to the collector power supply voltage. ；

[0019] The first capacitor C2 has one end connected to the input voltage and the other end grounded; the positive terminal of the second capacitor C3 is connected to pin 3 of U1, and the negative terminal is connected to pin 1 of U1.

[0020] The first resistor R4 is connected to the input voltage at one end and to the bidirectional transient suppressor diode D101 at the other end.

[0021] The second resistor R5 is connected to the source of MOSFET Q4 at one end and the drain of MOSFET Q4 at the other end; the third resistor R6 is connected to the gate of MOSFET Q4 at one end and the IRLED_CT network of the main control circuit at the other end.

[0022] One end of the bidirectional transient suppressor diode D101 is grounded, and the other end is connected to the first resistor R4;

[0023] The source of MOSFET Q4 is grounded.

[0024] In one possible implementation, the power supply circuit also includes a soft-start circuit;

[0025] The soft-start circuit includes a third capacitor C1, a field-effect transistor VT1, and a fourth resistor R3;

[0026] Among them, one end of the third capacitor C1 is connected to the source of the field-effect transistor VT1, and the other end is connected to the gate of the field-effect transistor VT1; one end of the fourth resistor R3 is connected to the gate of the field-effect transistor VT1, and the other end is grounded.

[0027] The drain of the field-effect transistor VT1 is connected to the input voltage terminal of the linear regulator U1, the source of the field-effect transistor VT1 is connected to the bidirectional transient suppressor diode D101, and the gate of the field-effect transistor VT1 is grounded through the fourth resistor R3.

[0028] In one possible implementation, in the power supply circuit, the second capacitor C3 is a polarized capacitor, the MOSFET Q4 is an N-channel MOSFET, and the field-effect transistor VT1 is a P-channel MOSFET.

[0029] In one possible implementation, the forward current flowing through the resistor in the temperature compensation circuit is I1, and the reverse leakage current of the temperature compensation circuit is I2.

[0030] Maintain the forward current emitted by the infrared emitter at I f The heat dissipation current of the infrared emitting tube is I. r ;

[0031] As the temperature rises, the I r Increase, while I1 remains unchanged, at this time I f =I1-I r +I2, maintaining the positive current I emitted by the infrared emitter. f The emission power of the infrared emitting tube at high temperatures remains essentially the same as that at room temperature.

[0032] In one possible implementation, the infrared receiving circuit is an infrared grating encoder circuit, and each I / O port of the infrared grating encoder circuit is connected to the circuit input voltage through a resistor.

[0033] When the infrared receiver tube receives an infrared signal, the IO state changes from the default high level to the low level. At this time, the main control circuit can determine the position of the infrared receiver tube by reading all the states through the IO.

[0034] In one possible implementation, the infrared emitting circuit also includes a communication circuit;

[0035] The communication circuit is used to send the working signal or working end signal from the host computer to the main control circuit;

[0036] The communication circuit is also used to upload the displacement data sent by the main control circuit to the host computer.

[0037] In one possible implementation, the MCU of the main control circuit is selected as a chip with an operating temperature of not less than 125℃;

[0038] The interface of the communication circuit uses a chip with an operating temperature of not less than 125℃.

[0039] The beneficial effects of the infrared emitting circuit provided by the embodiments of the present invention are as follows: An infrared emitting circuit is used to emit infrared signals to an infrared receiving circuit; the infrared receiving circuit includes multiple infrared receiving tubes; the infrared emitting circuit includes a temperature compensation circuit and infrared emitting tubes connected in parallel; the input terminal of the temperature compensation circuit is used to connect to a power supply, and the output terminal is connected to the infrared emitting tube; the temperature compensation circuit is used to adjust the emission power of the infrared emitting tube at high temperature so that the emission power of the infrared emitting tube at high temperature is consistent with that at normal temperature; the infrared emitting tube is used to emit infrared signals to the infrared receiving circuit so that the infrared receiving tube on the infrared receiving circuit responds to the infrared signals.

[0040] Its infrared emitting circuit transmits infrared signals to the infrared receiving circuit, which then responds upon receiving the signals, thus determining the conduction position of the infrared receiving tube. Furthermore, its temperature compensation circuit compensates for the increased heat dissipation current of the infrared emitting circuit at high temperatures, eliminating the impact of high temperatures on the infrared emitting tube and improving measurement accuracy at high temperatures. Its overall circuit structure enhances the accuracy of detection in harsh environments. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a structural diagram of an infrared emitting circuit provided in an embodiment of the present invention;

[0043] Figure 2 This is a circuit diagram of a temperature compensation circuit for an infrared emitting circuit provided in an embodiment of the present invention;

[0044] Figure 3 This is a circuit diagram of a power supply circuit for an infrared emitting circuit provided in an embodiment of the present invention;

[0045] Figure 4 This is a circuit diagram of an infrared grating encoder circuit for an infrared emitting circuit provided in an embodiment of the present invention;

[0046] Figure 5 This is a circuit schematic diagram of a communication circuit for an infrared emitting circuit provided in an embodiment of the present invention;

[0047] Figure 6 This is a circuit diagram of the main control circuit of an infrared emitting circuit provided in an embodiment of the present invention;

[0048] Figure 7 This is a system block diagram of an infrared emitting circuit provided in an embodiment of the present invention. Detailed Implementation

[0049] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0050] The term "comprising" and any other variations thereof in the specification, claims, and accompanying drawings of this invention mean "including but not limited to," and are intended to cover a non-exclusive inclusion, not limited to the examples listed herein. Furthermore, the terms "first" and "second," etc., are used to distinguish different objects, not to describe a specific order.

[0051] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments will be described below in conjunction with the accompanying drawings.

[0052] Figure 1 This is a structural diagram of an infrared emitting circuit provided by an embodiment of the present invention.

[0053] like Figure 1 As shown, the infrared transmitting circuit 10 is used to transmit infrared signals to the infrared receiving circuit 30; wherein, the infrared receiving circuit 30 includes a plurality of infrared receiving tubes 31;

[0054] The infrared emitting circuit 10 includes a temperature compensation circuit 11 and an infrared emitting tube 12; wherein, the input terminal of the temperature compensation circuit 11 is used to connect to the power supply 20, and the output terminal is connected to the infrared emitting tube 12; the temperature compensation circuit 11 is used to compensate for the increased heat dissipation current of the infrared emitting circuit 10 at high temperature, so as to ensure that the emission power of the infrared emitting tube 12 is the same at high temperature and at room temperature.

[0055] Infrared emitting tube 12 is used to transmit infrared signals to infrared receiving circuit 30 so that infrared receiving tube 31 on infrared receiving circuit 30 transmits the infrared signals.

[0056] In this embodiment, the infrared emitting circuit is capable of transmitting infrared signals to the infrared receiving circuit. The infrared emitting tube may include multiple infrared receiving tubes, which are capable of receiving infrared signals.

[0057] In the infrared emitting circuit, the temperature compensation circuit is connected in parallel with the infrared emitting tube. The input of the temperature compensation circuit is connected to the power supply, and the output is connected to the infrared emitting tube. When the infrared emitting circuit is operating at high temperature, the temperature compensation circuit compensates for the increased heat dissipation current of the infrared emitting circuit at high temperatures, ensuring that the emission power of the infrared emitting tube is consistent at high temperatures and room temperature. This keeps the power supply to the infrared emitting tube stable, so that the infrared signal emitted by the infrared emitting tube will only be received by the infrared receiving tube opposite it, and will not be received by other infrared receiving tubes, thus improving the accuracy of displacement detection at high temperatures.

[0058] In one possible implementation, the temperature compensation circuit includes a resistor and a diode, wherein the resistor and the diode are connected in parallel; the cathode of the diode constitutes the input terminal of the temperature compensation circuit, and the anode of the diode constitutes the output terminal of the temperature compensation circuit.

[0059] In this embodiment, the temperature compensation circuit includes a circuit and a diode, wherein the diode is connected in reverse to the circuit, with its cathode forming the input terminal and its anode forming the output terminal. This utilizes the fact that the reverse current of the diode increases with increasing temperature. Since the heat dissipation current flowing to the infrared emitting diode increases at high temperatures, the reverse diode can compensate for the heat dissipation current flowing to the infrared emitting diode, thereby stabilizing the infrared signal emitted by the infrared emitting diode and improving the measurement accuracy of the displacement detection sensor at high temperatures.

[0060] In a specific embodiment, such as Figure 2 As shown, the temperature compensation circuit includes resistors R1 and R2 and diodes D1, D2 and D3. The branch containing the diodes is connected in parallel with the branch containing the resistors.

[0061] In this circuit, the first resistor R1 and the second resistor R2 are connected in series, and the first diode D1, the second diode D2, and the third diode D3 are connected in parallel. The cathodes of the diodes form the input terminal of the temperature compensation circuit, and the anodes of the diodes form the output terminal. This design ensures that, at high temperatures, the reverse leakage current through the reverse diodes increases, compensating for the increased heat dissipation current and eliminating the impact of high temperatures on the infrared emitter, thus guaranteeing measurement accuracy. Furthermore, it ensures that the circuit continues to function normally even if one or two diodes fail.

[0062] The reason for using a diode in reverse is that when the temperature rises, the reverse saturation current of the diode increases, which can offset the increased leakage current in the infrared emitting circuit due to the high temperature, that is, the forward current flowing to the infrared emitting tube. This ensures that the emission power of the infrared emitting tube is consistent at high temperature and at room temperature, keeps the infrared intensity stable, and avoids more receiving tubes in the infrared receiving circuit from turning on.

[0063] The reason for using a diode and a resistor in parallel is that a strong back electromotive force is generated at the moment the circuit starts up, which can impact other components. However, when a resistor and a diode are connected in parallel, the resistor is short-circuited at the moment the circuit starts up, and at this time the resistor is equivalent to a capacitor. The reverse diode has a very large resistance, which is equivalent to a resistor. By connecting the resistor and capacitor in parallel, the back electromotive force can be consumed, reducing the impact on other components.

[0064] In one possible implementation, the infrared emitting circuit also includes a main control circuit and a power supply circuit.

[0065] The system includes a power supply circuit connected in series between the temperature compensation circuit and the power source; a main control circuit connected to the power supply circuit; a main control circuit sending a power supply command to the power supply circuit upon receiving a working signal; the working signal being a command issued by the host computer; a power supply command instructing the power supply circuit to turn on, so that the power source supplies power to the temperature compensation circuit; and a power-off command sending a power-off command to the power supply circuit upon receiving a work completion signal; the work completion signal being a command issued by the host computer after receiving the displacement data uploaded by the main control circuit; and a power-off command instructing the power supply circuit to turn off, so that the power source supplies power to the temperature compensation circuit.

[0066] In this embodiment, the main control circuit and the power supply circuit are connected, with the power supply circuit connected in series between the temperature compensation circuit and the power source. When the host computer sends a power supply command, it will power on the main control circuit. After the main control circuit receives the working signal, it will send a power supply command to instruct the power supply circuit to conduct. After the power supply circuit is conducted, the current flows to the infrared emitting tube after being processed by the temperature compensation circuit. The infrared emitting tube emits an infrared signal after being powered on.

[0067] After the main control circuit uploads the detected displacement to the host computer, the host computer will send a work completion signal. After the main control circuit receives the work completion signal, it will send a power-off command to the power supply circuit to shut down the power supply circuit so that the power supply is cut off to the temperature compensation circuit.

[0068] This ensures that the infrared emitting circuit operates in intermittent mode, which not only controls power consumption but also increases the lifespan of the infrared emitting tube.

[0069] Figure 3 This is a circuit diagram of the power supply circuit for an infrared emitting circuit provided in an embodiment of the present invention.

[0070] like Figure 3 As shown, the power supply circuit includes a linear regulator U1, a second capacitor C2, a third capacitor C3, a third resistor R4, a fourth resistor R5, a fifth resistor R6, a MOSFET Q4, and a bidirectional transient suppressor diode D101.

[0071] The input terminal of the linear regulator U1 is the input terminal of the power supply circuit, and the output terminal of the linear regulator U1 is the output terminal of the power supply circuit. The output terminal of the linear regulator U1 includes pins 1, 2, 3, and 4. Pin 1 is grounded, pins 2 and 4 are connected to the input voltage, and pin 3 is connected to the collector power supply voltage. ；

[0072] The first capacitor C2 has one end connected to the input voltage and the other end grounded; the positive terminal of the second capacitor C3 is connected to pin 3 of U1, and the negative terminal is connected to pin 1 of U1.

[0073] The third resistor R4 is connected to the input voltage at one end and to the bidirectional transient suppressor diode D101 at the other end.

[0074] MOSFET Q4 is connected to the power supply circuit via a six-pin connector;

[0075] The fourth resistor R5 is connected to the source of MOSFET Q4 at one end and the drain of MOSFET Q4 at the other end; the fifth resistor R6 is connected to the gate of MOSFET Q4 at one end and the IRLED_CT network of the main control circuit at the other end.

[0076] One end of the bidirectional transient suppressor diode D101 is grounded, and the other end is connected to the first resistor R4;

[0077] The source of MOSFET Q4 is grounded.

[0078] In this embodiment, the infrared emitting circuit can be applied to a displacement detection sensor. After the main control circuit receives the working signal, the linear regulator U1 in the power supply circuit can be connected to a 5V input voltage, and the linear regulator U1 can output a 3.3V voltage. After the power supply circuit is powered on, the main control circuit controls the MOSFET Q4 to turn on and off through the IRLED_CT network. When the IRLED_CT network is high, the MOSFET Q4 is turned on, the infrared emitting circuit is powered on, the infrared emitting diode emits an infrared signal, the infrared receiving board responds to the infrared signal, and the displacement detection sensor begins sampling; when the IRLED_CT network is low, the MOSFET Q4 is turned off, the infrared emitting circuit is powered off, and the displacement detection sensor ends sampling.

[0079] This embodiment controls the power supply and de-energization of the infrared emitting circuit by controlling the switching on and off of the MOSFET Q4 in the power supply circuit. The infrared emitting circuit is only powered on when the displacement detection sensor starts sampling, thereby controlling the power consumption of the device.

[0080] In one possible implementation, the power supply circuit also includes a soft-start circuit;

[0081] The soft-start circuit includes a third capacitor C1, a field-effect transistor VT1, and a third resistor R3;

[0082] Among them, one end of the third capacitor C1 is connected to the source of the field-effect transistor VT1, and the other end is connected to the gate of the field-effect transistor VT1; one end of the fourth resistor R3 is connected to the gate of the field-effect transistor VT1, and the other end is grounded.

[0083] The drain of the field-effect transistor VT1 is connected to the input voltage terminal of the linear regulator U1, the source of the field-effect transistor VT1 is connected to the bidirectional transient suppressor diode D101, and the gate of the field-effect transistor VT1 is grounded through the sixth resistor R3.

[0084] In this embodiment, since each power supply board is connected to a filter capacitor, a large inrush current will be generated when the power supply jumps during power-on due to the charging of the capacitor. This will cause the power supply voltage to drop, resulting in serious defects such as system reset and repeated restarts. Therefore, a soft-start circuit is needed to reduce the inrush current during power-on.

[0085] The sixth resistor R3 and the third capacitor C1 form a voltage divider RC time constant circuit. C1 is connected in parallel between the source and gate of VT1. The voltage across the third capacitor C1 is Vc1, and the voltage between the gate and source of the MOSFET VT1 is Vgs, meaning Vc1 = Vgs. When power is first applied to the board, C1 is not charged, Vgs = 0, VT1 is not conducting, and the power module does not supply power. Subsequently, the voltage charges C7. When the voltage across C7 reaches the threshold voltage Vth, VT1 begins to conduct.

[0086] After VT1 starts conducting, the voltage Vgs between its source and gate continues to increase, while the resistance Rds between its drain and source decreases rapidly. The output voltage gradually rises until it is basically consistent with the input voltage. The power module starts working, and the board is officially powered on. During this process, the output voltage does not jump to its highest point instantaneously, thus greatly reducing the interference of inrush current. The time of this process is related to the charging speed of C1, the characteristics of VT1, and the load characteristics, and can be adjusted as needed.

[0087] In one possible implementation, in the power supply circuit, the second capacitor C3 can be a polarized capacitor, the MOSFET Q4 can be an N-channel MOSFET, and the field-effect transistor VT1 can be a P-channel MOSFET.

[0088] In this embodiment, the positive terminal of the second capacitor C3 is connected to pin 3 of U1, and the negative terminal is connected to pin 1 of U1. Pin 3 of U1 is Vout, and pin 1 is GND. It can be determined that the second capacitor C3 is a bypass capacitor. The bypass capacitor is actually a decoupling capacitor. Its function is to filter out the interference of the output signal. By charging and discharging it, the amplified signal will not be disturbed by sudden changes in current. It requires the capacitor to have a large capacitance. Since polarized capacitors are usually electrolytic capacitors, they have a very large capacitance. Therefore, the second capacitor C3 is a polarized capacitor.

[0089] In this embodiment, MOSFET Q4 is used as a switch to control the power supply of the temperature compensation circuit. Typically, an N-channel MOSFET is selected as the switch. When the correct polarity and magnitude of the voltage are applied between the source and drain, and then a control voltage is applied between the gate and source, a current of the corresponding magnitude will flow from the source to the drain. When the signal voltage is large enough, the circuit containing MOSFET Q4 can saturate instantly and become a switch.

[0090] In this embodiment, the field-effect transistor VT1 is used for soft start. Typically, a P-channel MOSFET is selected for soft start, and the soft start function is achieved by connecting a series resistor and a parallel capacitor.

[0091] In one possible implementation, such as Figure 2 As shown, in the temperature compensation circuit, the forward current flowing through the resistor is I1, and the reverse leakage current of the temperature compensation circuit is I2.

[0092] Maintain the forward current emitted by the infrared emitter at I f The heat dissipation current of the infrared emitting tube is Ir;

[0093] As the temperature rises, the I r Increase, while I1 remains unchanged, at this time I f =I1-I r +I2, maintaining the positive current I emitted by the infrared emitter. f The emission power of the infrared emitting tube at high temperatures remains essentially the same as that at room temperature.

[0094] Figure 4 This is a circuit diagram of an infrared grating encoder circuit for an infrared emitting circuit provided in an embodiment of the present invention.

[0095] Each I / O port of the infrared grating encoder circuit is connected to the circuit input voltage through a resistor;

[0096] When the infrared receiver tube receives an infrared signal, the IO state changes from the default high level to the low level. At this time, the main control circuit can determine the position of the infrared receiver tube by reading all the states through the IO.

[0097] Specifically, when the infrared receiver receives the infrared signal emitted by the infrared transmitter, the IO state changes from the default high level to the low level. The CD4051 port and P0_OUT port of the infrared encoder circuit are connected to the main control circuit. The main control circuit can read all the states through the IO to determine the position of the infrared receiver and calculate the corresponding displacement based on the position.

[0098] Figure 5 This is a circuit diagram of a communication circuit for an infrared emitting circuit provided in an embodiment of the present invention.

[0099] In this embodiment, the infrared emitting circuit also includes a communication circuit; the communication circuit is connected to the main control circuit through pins 1, 2, 3 and 4, and J485A and J485B are connected to the host computer through the external interface of the power supply circuit.

[0100] On the one hand, the communication circuit is used to send the working signal or working end signal from the host computer to the main control circuit; on the other hand, the communication circuit is also used to upload the displacement amount sent by the main control circuit to the host computer.

[0101] Specifically, through the communication circuit, the host computer can send working signals to the main control circuit, and the main control circuit can upload the displacement measured by the displacement detection sensor to the host computer.

[0102] Figure 6 This is a circuit diagram of the main control circuit of an infrared emitting circuit provided in an embodiment of the present invention.

[0103] Specifically, the IRLED_CT port of the main control circuit is connected to the sixth resistor of the power supply circuit to turn off the MOSFET Q4. By controlling the turn-off and turn-on of Q4, the power supply to the infrared emitting circuit is turned off and powered on. The 485RE interface of the main control circuit is connected to the communication circuit to send power supply signals to the power supply circuit and to upload the specific displacement to the host computer. The main control circuit is also connected to the CD4051 port and P0_OUT port of the infrared encoder circuit. By reading all the states of the infrared encoder circuit, the position of the infrared receiving tube can be determined.

[0104] In one possible implementation, the MCU of the main control circuit is selected as a chip with an operating temperature of not less than 125°C; the interface of the communication circuit is selected as a chip with an operating temperature of not less than 125°C.

[0105] In displacement sensors, an infrared emitting circuit can be considered part of the sensor itself. The infrared emitting diode in the infrared emitting circuit transmits infrared signals to the infrared receiving circuit, causing the infrared receiving diode in the receiving circuit to respond. The main control circuit in the infrared emitting circuit can determine the conduction position of the infrared receiving diode by reading all the states of the infrared encoder circuit's I / O, and thus calculate the specific displacement. Because displacement sensors operate in harsh environments, the circuit design must consider not only the impact of high temperatures on the internal structure of the circuit, but also whether the components in the circuit can withstand high-temperature operating environments. To ensure the normal operation of the device, all components selected in the circuit must be able to withstand high-temperature environments.

[0106] Figure 7 This is a system block diagram of an infrared emitting circuit provided in an embodiment of the present invention.

[0107] In this embodiment, the infrared emitting circuit can be applied to a pipe deformation displacement detection sensor. The host computer can preset the sampling interval to control the pipe deformation displacement detection sensor to operate intermittently. During each sampling cycle, the host computer sends a working signal to the main control circuit via the RS485 communication circuit while simultaneously supplying power to the pipe deformation displacement detection sensor. After the main control circuit is powered on, it controls the MOSFET Q4 in the power supply circuit to conduct. Once MOSFET Q4 is turned on, the power supply circuit delivers current to the temperature compensation circuit. After processing by the temperature compensation circuit, the current flows to the infrared emitting diode, which emits 940nm infrared light.

[0108] In the infrared circuit, the infrared receiver tube and the infrared transmitter tube emit infrared signals to each other. When the infrared receiver tube receives the infrared signal, the corresponding IO port in the infrared encoder circuit will change from high level to low level. The MCU can detect the status of all IO ports and receive their conduction signals. That is, the MCU can read the conduction position of the infrared receiver tube by acquiring the status of the IO ports, and then perform corresponding calculations. After calculating the specific displacement of this sampling, the calculation result is uploaded to the host computer through the RS485 communication circuit.

[0109] After receiving the sampling results, the host computer will send a sampling end command to the main control circuit through the RS485 communication circuit, which will cause the main control circuit to turn off the MOSFET Q4 in the power supply circuit to cut off the power to the infrared emitting tube.

[0110] After sampling, the host computer will store the calculation results and compare them with the critical value of pipeline deformation displacement built into the system. When the specific value of pipeline deformation displacement is close to the critical value, the system will issue an alarm to remind relevant personnel to repair or replace the pipeline.

[0111] The infrared emitting circuit provided in this embodiment of the invention can monitor displacement. Its temperature compensation circuit not only increases the reverse leakage current as the temperature rises, but also compensates for the increased heat dissipation current of the infrared emitting circuit at high temperatures, ensuring that the emission power of the infrared emitting tube is consistent at high temperatures and room temperature, thus increasing the measurement accuracy at high temperatures. In addition, it can selectively supply power to ensure that the circuit works in intermittent mode, control the power consumption of the device, and enable the overall circuit structure to perform displacement detection in harsh environments.

[0112] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An infrared emitting circuit, characterized in that, Used to transmit infrared signals to an infrared receiving circuit; the infrared receiving circuit includes multiple infrared receiving tubes; The infrared emitting circuit includes a temperature compensation circuit and an infrared emitting tube; The input terminal of the temperature compensation circuit is used to connect to the power supply, and the output terminal is connected to the infrared emitting tube; the temperature compensation circuit is used to compensate for the increased heat dissipation current of the infrared emitting circuit at high temperatures, so as to ensure that the emission power of the infrared emitting tube is the same at high temperatures and at room temperature. The infrared emitting diode is used to transmit the infrared signal to the infrared receiving circuit, so that the infrared receiving diode on the infrared receiving circuit responds to the infrared signal; The temperature compensation circuit includes a resistor and a diode, wherein the resistor and the diode are connected in parallel. The cathode of the diode forms the input terminal of the temperature compensation circuit, and the anode of the diode forms the output terminal of the temperature compensation circuit. In the temperature compensation circuit, the forward current flowing through the resistor is I1, and the reverse leakage current of the temperature compensation circuit is I2. maintain the forward current emitted by the infrared emitting tube at I f , the infrared emitting tube thermal dissipation current at I r ; The relationship between the forward current flowing through the resistor, the reverse leakage current, the forward current maintaining the emission of the infrared emitting diode, and the heat dissipation current of the infrared emitting diode is as follows: I f =I1-I r +I2 In the formula, as the temperature increases, the I r As I increases, I1 remains unchanged.

2. The infrared emitting circuit according to claim 1, characterized in that, The infrared emitting circuit also includes a main control circuit and a power supply circuit; The power supply circuit is connected in series between the temperature compensation circuit and the power source; The main control circuit and the power supply circuit are connected; The main control circuit is used to send a power supply command to the power supply circuit when it receives a working signal; wherein, the working signal is a working command issued by the host computer; the power supply command is used to instruct the power supply circuit to be turned on so that the power supply can supply power to the temperature compensation circuit. The main control circuit is also used to send a power-off command to the power supply circuit when a work completion signal is received; wherein, the work completion signal is a work completion command issued by the host computer after receiving the displacement amount uploaded by the main control circuit; the power-off command is used to instruct the power supply circuit to turn off, so that the power supply is disconnected from the temperature compensation circuit.

3. The infrared emitting circuit according to claim 2, characterized in that, The power supply circuit includes a linear regulator U1, a first capacitor C2, a second capacitor C3, a first resistor R4, a second resistor R5, a third resistor R6, a MOSFET Q4, and a bidirectional transient suppression diode D101. The input terminal of the linear regulator U1 is the input terminal of the power supply circuit, and the output terminal of the linear regulator U1 is the output terminal of the power supply circuit. The output terminal of the linear regulator U1 includes pin 1, pin 2, pin 3 and pin 4. Pin 1 is grounded, pin 2 and pin 4 are connected to the input voltage, and pin 3 is connected to the collector power supply voltage. The first capacitor C2 has one end connected to the input voltage and the other end grounded; the positive terminal of the second capacitor C3 is connected to pin 3 of U1, and the negative terminal is connected to pin 1 of U1. One end of the first resistor R4 is connected to the input voltage, and the other end is connected to the bidirectional transient suppression diode D101; The second resistor R5 is connected to the source of MOSFET Q4 at one end and to the drain of MOSFET Q4 at the other end; the third resistor R6 is connected to the gate of MOSFET Q4 at one end and to the IRLED_CT network of the main control circuit at the other end. One end of the bidirectional transient suppression diode D101 is grounded, and the other end is connected to the first resistor R4; The source of the MOS transistor Q4 is grounded.

4. The infrared emitting circuit according to claim 3, characterized in that, The power supply circuit also includes a soft-start circuit; The soft-start circuit includes the third capacitor C1, the field-effect transistor VT1, and the fourth resistor R3; The third capacitor C1 is connected to the source of the field-effect transistor VT1 at one end and to the gate of the field-effect transistor VT1 at the other end; the fourth resistor R3 is connected to the gate of the field-effect transistor VT1 at one end and to ground at the other end. The drain of the field-effect transistor VT1 is connected to the input voltage terminal of the linear regulator U1, the source of the field-effect transistor VT1 is connected to the bidirectional transient suppressor diode D101, and the gate of the field-effect transistor VT1 is grounded through the fourth resistor R3.

5. The infrared emitting circuit according to claim 4, characterized in that, In the power supply circuit, the second capacitor C3 is a polarized capacitor, the MOSFET Q4 is an N-channel MOSFET, and the field-effect transistor VT1 is a P-channel MOSFET.

6. The infrared emitting circuit according to claim 2, characterized in that, The infrared receiving circuit is an infrared grating encoder circuit, and each IO port of the infrared grating encoder circuit is connected to the circuit input voltage through a resistor. When the infrared receiver receives the infrared signal, the IO state changes from the default high level to the low level. At this time, the main control circuit can determine the position of the infrared receiver by reading all the states through the IO.

7. The infrared emitting circuit according to claim 2, characterized in that, The infrared emitting circuit also includes a communication circuit; The communication circuit is used to send the working signal or working end signal issued by the host computer to the main control circuit; The communication circuit is also used to upload the displacement amount sent by the main control circuit to the host computer.

8. The infrared emitting circuit according to claim 7, characterized in that, The MCU of the main control circuit is selected from chips with an operating temperature of not less than 125℃; The interface of the communication circuit uses a chip with an operating temperature of not less than 125℃.

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