Feedback Circuit for Improving the Measurement Accuracy of Strain Sensors

Abstract

The present application relates to a feedback circuit for improving the measurement accuracy of a strain sensor, including: a power supply circuit, an operational amplifier chip, and a filtering circuit. The power supply circuit is electrically connected to the operational amplifier chip to supply power to the operational amplifier chip. The input end of the filtering circuit is electrically connected to the operational amplifier chip, and the output end is adapted to be electrically connected to the reference voltage terminal of the AD chip. A filtering circuit is added between the operational amplifier and the AD to solve the problem of unstable data caused by overshoot. By adding a filtering circuit composed of a resistor and a switching diode between the operational amplifier chip and the AD chip, when the sensor feedback signal changes slightly due to a small external strain, the operational amplifier chip can amplify it to an amplitude range that is more convenient for subsequent circuit processing, while ensuring the linearity of the signal, which helps to avoid measurement errors caused by signal distortion during the signal amplification process, thereby improving the measurement accuracy.

Description

Technical Field

[0001] The present application relates to the technical field of sensors, and in particular, to a feedback circuit for improving the measurement accuracy of a strain sensor. Background Art

[0002] The measurement principle of a strain sensor is based on a Wheatstone bridge. Its characteristic is that the output voltage is very small. Under a 10V supply bridge, the bridge output is only about 20mV. The sensor needs to be connected to an instrument through a cable to obtain measurement data. Since the core wire of the cable is made of copper, and the resistance temperature coefficient of copper is about 0.004 / °C, the cable will affect the output sensitivity of the sensor due to its own resistance, and ultimately affect the measurement accuracy of the measurement system. Generally, to improve the measurement accuracy, two feedback terminals are added at the bridge supply end. When the supply voltage of the sensor changes due to the change in the wire resistance, the voltage at the feedback terminal also changes accordingly. The two feedback wires are directly connected to the feedback terminal of the AD. The input signal voltage and the reference voltage of the AD have the same change in the supply bridge voltage, so as to eliminate the sensitivity change caused by the wire resistance. However, directly adding two feedback wires at the bridge supply end results in a relatively large data drift and a large data jump, and high-precision measurement cannot be achieved. Summary of the Invention

[0003] In view of this, the present application proposes a feedback circuit for improving the measurement accuracy of a strain sensor.

[0004] According to one aspect of the present application, there is provided a feedback circuit for improving the measurement accuracy of a strain sensor, including:

[0005] A power supply circuit, an operational amplifier chip, and a filter circuit;

[0006] The power supply circuit is electrically connected to the operational amplifier chip to supply power to the operational amplifier chip;

[0007] The input end of the filter circuit is electrically connected to the electrical terminal of the operational amplifier chip, and the output end is adapted to be electrically connected to the reference voltage of the AD chip to avoid overshoot.

[0008] In a possible implementation manner, the pin 1 and pin 3 of the operational amplifier chip are adapted to be electrically connected to the feedback terminal of the sensor.

[0009] In a possible implementation manner, it further includes a resistor R9 and a resistor R12;

[0010] The pin 4 and pin 5 of the operational amplifier chip are short-circuited and electrically connected to the resistor R9 and the resistor R12 to participate in signal regulation.

[0011] In a possible implementation, the R13 resistor is shorted to the R9 resistor and electrically connected to the negative terminal of the reference voltage of the AD chip for signal processing.

[0012] In a possible implementation, it further includes: an R10 resistor and an R8 resistor;

[0013] The 7-pin and 8-pin of the operational amplifier chip are shorted and electrically connected to the R10 resistor and the R8 resistor to process and transmit signals.

[0014] In a possible implementation, the R10 resistor is electrically connected to the R11 resistor, and the R8 resistor is shorted to the R11 resistor and electrically connected to the positive terminal of the reference voltage of the AD chip to ensure the circuit function.

[0015] In a possible implementation, it further includes: an R13 resistor, a D7 diode, a D6 diode, a D5 diode, and a D4 diode;

[0016] The R12 resistor is electrically connected to the R13 resistor and the negative electrode of the D7 diode. The positive electrode of the D7 diode is electrically connected to the negative electrode of the D6 diode. The positive electrode of the D6 diode is electrically connected to the negative electrode of the D5 diode. The positive electrode of the D5 diode is electrically connected to the negative electrode of the D4 diode. The positive electrode of the D4 diode is electrically connected to the R10 resistor and the R11 resistor respectively.

[0017] In a possible implementation, the power supply circuit includes: a power management chip, a C5 capacitor, and a D3 diode;

[0018] The 2-pin of the power management chip is electrically connected to the negative electrode of the C5 capacitor. The positive electrode of the C5 capacitor is electrically connected to the positive electrode of the D3 diode. The negative electrode of the D3 diode is connected to the 6-pin of the power management chip.

[0019] In a possible implementation, it further includes: a C7 capacitor;

[0020] The positive electrode of the D3 diode is electrically connected to the negative electrode of the C7 capacitor. The positive electrode of the C7 capacitor is electrically connected to the 2-pin of the operational amplifier chip.

[0021] In a possible implementation, it further includes: a D2 diode;

[0022] The 8-pin of the power management chip is adapted to be electrically connected to a power supply and is electrically connected to the operational amplifier chip through the D2 diode and the D3 diode.

[0023] The beneficial effects of the feedback circuit for improving the measurement accuracy of the strain sensor of the embodiment of the present application are as follows: In order to solve the matching problem between the feedback circuit and the AD chip, a feedback voltage follower is used in the feedback circuit, and there is almost no voltage drop, attenuation or distortion between the input voltage and the output voltage, ensuring that the output voltage is consistent with the input voltage. In order to prevent the output voltage of the op amp from rising when the AD sampling is nearly completed, but the output voltage conversion rate of the op amp is limited and cannot be corrected in time, causing overshoot, a filter circuit is added between the op amp and the AD to solve the data instability caused by overshoot. Specifically, a filter circuit composed of a resistor and a switching diode is added between the op amp chip and the AD chip. When the sensor feedback signal changes slightly due to a slight external strain, the op amp chip can amplify it to an amplitude range that is easier for subsequent circuits to process, while ensuring the linearity of the signal, which helps to avoid measurement errors caused by distortion during signal amplification, thereby improving measurement accuracy.

[0024] Other features and aspects of the present application will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the present application and, together with the description, serve to explain the principles of the present application.

[0026] Figure 1 A schematic diagram showing a feedback circuit for improving the measurement accuracy of a strain sensor according to an embodiment of the present application;

[0027] Figure 2 A circuit diagram of a power module according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0028] Various exemplary embodiments, features and aspects of the present application will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0029] Among them, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention or simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0030] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0031] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0032] In addition, in order to better illustrate the present application, numerous specific details are given in the following specific embodiments. It should be understood by those skilled in the art that the present application can also be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present application.

[0033] like Figure 1 and Figure 2 As shown, the feedback circuit for improving the measurement accuracy of the strain type sensor in the embodiment of the present application includes: a power supply circuit, an operational amplifier chip 10 and a filtering circuit. The power supply circuit is electrically connected to the operational amplifier chip 10 to supply power to the operational amplifier chip 10. The input end of the filtering circuit is electrically connected to the operational amplifier chip 10, and the output end is suitable for connection to the reference voltage terminal of the AD chip to avoid overshoot.

[0034] In this specific embodiment, in order to solve the matching problem between the feedback circuit and the AD chip, a feedback voltage follower is used in the feedback circuit. There is almost no voltage drop, attenuation or distortion between the input voltage and the output voltage, ensuring that the output voltage is consistent with the input voltage. In order to prevent the output voltage of the op amp from rising when the AD sampling is almost completed, but the output voltage conversion rate of the op amp is limited and cannot be corrected in time, causing overshoot, a filter circuit is added between the op amp and the AD to solve the data instability caused by overshoot. Specifically, a filter circuit composed of a resistor and a switching diode is added between the op amp chip 10 and the AD chip. When the sensor feedback signal changes slightly due to a slight external strain, the op amp chip 10 can amplify it to an amplitude range that is easier for subsequent circuits to process, while ensuring the linearity of the signal, which helps to avoid measurement errors caused by distortion during signal amplification, thereby improving measurement accuracy.

[0035] In a specific embodiment, pin 1 and pin 3 of the operational amplifier chip 10 are adapted to be electrically connected to the feedback terminal of the sensor. Pin 1 and pin 3 of the operational amplifier chip 10 are specifically designed to establish an electrical connection with the feedback terminal of the sensor, and can effectively transmit the signal fed back by the sensor into the operational amplifier chip 10. As the front-end device for measuring strain, these signals are often relatively weak and need to be processed and amplified subsequently by the operational amplifier chip 10. By connecting pin 1 and pin 3 of the operational amplifier chip 10 to the feedback terminal of the sensor, it lays the foundation for the subsequent signal processing flow.

[0036] In a specific embodiment, it further includes resistor R9 15 and resistor R12 14. Pin 4 and pin 5 of the operational amplifier chip 10 are short-circuited and electrically connected to resistor R9 15 and resistor R12 14, participating in signal regulation and jointly participating in the signal regulation process, which helps to optimize the stability and accuracy of the signal. Specifically, pin 4 and pin 5 of the operational amplifier chip 10 are short-circuited, and they are electrically connected to resistor R9 15 and resistor R12 14 to participate in signal regulation. Signal regulation is achieved through the voltage division and current limiting characteristics of the resistors. When the signal is output from pin 4 and pin 5 of the operational amplifier chip 10, it will pass through the resistor network formed by resistor R9 15 and resistor R12 14. Among them, different resistance values will affect the current and voltage passing through them, thereby regulating the signal. For example, assuming the signal is a voltage signal, when passing through resistor R9 and resistor R12 14, the voltage will be distributed according to the ratio of the resistors, so that the characteristics such as the amplitude and phase of the output signal are adjusted.

[0037] In a specific embodiment, it further includes: R13 resistor 16, D7 diode 20, D6 diode 19, D5 diode 18, and D4 diode 17. The R12 resistor 14 is electrically connected to the negative electrodes of the R13 resistor 16 and the D7 diode 20. The positive electrode of the D7 diode 20 is electrically connected to the negative electrode of the D6 diode 19. The positive electrode of the D6 diode 19 is electrically connected to the negative electrode of the D5 diode 18. The positive electrode of the D5 diode 18 is electrically connected to the negative electrode of the D4 diode 17. The positive electrode of the D4 diode 17 is electrically connected to the R10 resistor 12 and the R11 resistor 13 respectively, which helps to improve the stability and response speed of the circuit. Specifically, the series or parallel combination of the R13 resistor 16 and the R12 resistor 14 further adjusts the characteristics of the signal. The R13 resistor 16 and the R12 resistor 14 can change the attenuation degree or voltage division ratio of the signal, and perform more precise adjustment on the signal. The addition of the D7 diode 20 introduces a non-linear element. The diode has unidirectional conductivity. When it is forward-conducting, its conduction voltage is relatively stable. When the signal passes through the D7 diode 20, its negative electrode will limit the voltage range of the signal. For the forward signal, it will clamp the signal according to its own conduction voltage to prevent the amplitude of the signal from exceeding a certain range, playing a role in protecting the subsequent circuit. For the reverse signal, due to the reverse cut-off characteristic of the diode, it will prevent the reverse signal from passing through, avoiding interference to the circuit, thus ensuring the stability of the circuit and the forward transmission of the signal, and at the same time avoiding possible signal distortion and interference, ensuring that the performance of the circuit meets the expectations.

[0038] Among them, the positive electrode of the D7 diode 20 is connected to the negative electrode of the D6 diode 19, forming a series connection method. Similarly, the positive electrode of the D6 diode 19 is connected to the negative electrode of the D5 diode 18, and the positive electrode of the D5 diode 18 is connected to the negative electrode of the D4 diode 17. This connection method continues the series circuit structure. Finally, the positive electrode of the D4 diode 17 is connected to the R10 resistor 12 and the R11 resistor 13 respectively, forming a branched circuit structure, and the current can flow from the positive electrode of the D4 diode 17 to the R10 resistor 12 and the R11 resistor 13 respectively. Specifically, between the R12 resistor 14 and the positive electrode of the D4 diode 17, the voltage will gradually decrease, forming a voltage division circuit for adjusting or stabilizing the voltage of a certain circuit node. In the feedback circuit, such a diode chain can be used as a non-linear element to provide a certain form of non-linear feedback for changing the gain, stability or frequency response of the circuit. When the input voltage is too high, a certain diode in the diode chain may first break down and conduct a large amount of current, thus protecting other more sensitive components from damage.

[0039] In a specific embodiment, the R13 resistor and the 16R9 resistor are short - circuited and electrically connected to the negative terminal of the reference voltage of the AD chip for signal processing. The operational amplifier chip 10 can work in cooperation with the AD chip to jointly complete the signal processing task. Specifically, the processed signal is transmitted to the negative terminal of the reference voltage of the AD chip. When the signal reaches the negative terminal of the reference voltage of the AD chip, it provides an important reference benchmark for the conversion process of the AD chip. It provides an accurate reference for the conversion of the AD chip, which helps to improve the conversion accuracy of the AD chip. For example, during the AD conversion process, the signal at the negative terminal of the reference voltage is compared with the input analog signal. An accurate reference voltage can enable the AD chip to convert the analog signal into a digital signal more precisely, thereby improving the measurement accuracy of the entire measurement system.

[0040] In a specific embodiment, it further includes: the R10 resistor 12 and the R8 resistor 11. The 7 - pin and 8 - pin of the operational amplifier chip 10 are short - circuited and electrically connected to the R10 resistor 12 and the R8 resistor 11 to process and transmit the signal, ensuring the integrity of the circuit function and enabling the entire circuit to work properly. Specifically, the R10 and R8 resistors 11 further process the signal output from the operational amplifier chip 10 by voltage division and current limiting of the signal, so as to better cooperate with other circuit components. At the same time, through this electrical connection, the signal can be effectively transmitted to the subsequent circuit part, ensuring the normal flow of the signal in the circuit and the coherence of the processing flow.

[0041] In a specific embodiment, the R10 resistor 12 is electrically connected to the R11 resistor 13, and the R8 resistor 11 is short - circuited to the R11 resistor 13 and electrically connected to the positive terminal of the reference voltage of the AD chip to ensure the circuit function.

[0042] In a specific embodiment, the power supply circuit includes: a power management chip 21, a C5 capacitor, and a D3 diode 24. The 2 - pin of the power management chip 21 is electrically connected to the negative terminal of the C5 capacitor, the positive terminal of the C5 capacitor is electrically connected to the positive terminal of the D3 diode 24, and the negative terminal of the D3 diode 24 is connected to the 6 - pin of the power management chip 21 to form a stable power supply circuit to provide reliable power support for the operational amplifier chip 10. Specifically, through such a connection, a carefully processed signal is provided for the positive terminal of the reference voltage of the AD chip. Similar to the negative terminal of the reference voltage, the signal at the positive terminal of the reference voltage is also a key reference in the AD conversion process, and its stability and accuracy are crucial for the result of the AD conversion. The combination of the R10, R11, and R8 resistors 11 makes a final adjustment and optimization of the signal, ensuring that the signal input to the positive terminal of the reference voltage of the AD chip is accurate and stable.

[0043] Among them, the power management chip 21 is responsible for providing the electrical energy required for the entire circuit. When the power management chip 21 outputs electrical energy, there may be certain ripples and noises in its output. The C5 capacitor can store and release charges through the charge and discharge process, smooth the power supply voltage, and reduce the voltage fluctuation. The D3 diode 24 has multiple functions here. On the one hand, it can prevent the reverse voltage of the power supply from damaging the power management chip 21 or other circuit components, and utilize its unidirectional conductivity to ensure that the current can only flow in the forward direction. On the other hand, it can also clamp the power supply voltage to a certain extent to protect the circuit from the impact of excessive voltage.

[0044] In a specific embodiment, it further includes: a C7 capacitor 25 and a D2 diode 23. The positive electrode of the D3 diode 24 is electrically connected to the negative electrode of the C7 capacitor 25, the positive electrode of the C7 capacitor 25 is electrically connected to the 2-pin of the operational amplifier chip 10. The 8-pin of the power management chip 21 is suitable for being electrically connected to the power supply, and is electrically connected to the operational amplifier chip through the D2 diode 23 and the D3 diode 24, making the power supply circuit more stable and reliable, and providing a strong guarantee for the normal operation of the entire system.

[0045] Among them, the C7 capacitor 25 further enhances the filtering effect of the power supply, especially for the power input of the 2-pin of the operational amplifier chip 10. By filtering the power input again, it can provide a more stable power supply for the operational amplifier chip 10, reduce the impact of power supply noise on the operation of the operational amplifier chip 10, and the presence of the C7 capacitor 25 helps to ensure that the operational amplifier chip 10 works in a stable power supply environment, avoiding signal processing errors or performance degradation caused by power supply fluctuations, and further ensuring the reliability of the entire circuit and the accuracy of measurement. The D2 diode 23 and the D3 diode 24 together constitute the connection path of the power supply, transmitting the output power of the power management chip 21 to the operational amplifier chip 10. The D2 diode 23 can prevent excessive voltage in the power supply from entering the operational amplifier chip 10. When the power supply voltage exceeds the forward conduction voltage of the D2 diode 23, it will bypass the excess voltage to avoid damaging the operational amplifier chip 10. At the same time, the cooperation of the D2 diode 23 and the D3 diode 24 provides a stable power supply path for the operational amplifier chip 10, ensuring that the operational amplifier chip 10 can work stably under various power supply conditions, guaranteeing the reliability of the power supply of the entire circuit, and being an important guarantee for the normal operation of the entire circuit.

[0046] According to the above content, the feedback circuit consists of an operational amplifier chip 10. Its pin 1 and pin 3 are respectively connected to the feedback terminals of the sensor, and the power supply terminals of pins 2 and 6 are provided by a power management chip 21. After the pin 4 and pin 5 of the operational amplifier are short-circuited, they are respectively connected to one end of a 1k resistor R9 and one end of a 300Ω resistor R12. The other end of the R12 resistor 14 is connected to the negative pole of a 2.4M resistor R13 and a switching diode D7. The other end of the resistor R13 is connected to the other end of R9, and then connected to the VERF- terminal of the AD chip. The positive pole of the diode D7 is connected to the negative pole of the diode D6, and the positive pole of D6 is connected to the negative pole of the diode D5. The positive pole of the diode D5 is connected to the negative pole of the diode D4, and the positive pole of D4 is respectively connected to a 300Ω resistor R10 and a 2.4M resistor R11. After the pin 7 and pin 8 of the operational amplifier chip 10 are short-circuited, they are connected to one end of the 300Ω R10 resistor 12, and at the same time connected to the 1k R8 resistor 11. The other end of the resistor R8 is connected to the resistor R11 and then enters the VREF+ of the AD chip.

[0047] Among them, the power supply of the operational amplifier chip 10 is provided by the power management chip 21. Pin 1, pin 3, pin 6, and pin 7 of the power management chip 21 are left floating and not connected. Pin 2 is connected to the negative pole of a 22uF C5 capacitor. The positive pole of the C5 capacitor is connected to the positive pole of a D3 diode 24. The negative pole of the D3 diode 24 is connected to pin 6 of the operational amplifier chip 10. The positive pole of the D3 diode 24 is connected to the negative pole of a 100pF C5 capacitor. The positive pole of the C7 capacitor 25 is connected to pin 2 of the operational amplifier chip 10. The negative pole of D3 is also connected to the positive pole of a 22uF C6 capacitor. The negative pole of the C6 capacitor is grounded. Pin 2 of the power management chip 21 is simultaneously connected to the positive pole of a 22uF C4 capacitor. The negative pole of the C4 capacitor is connected to pin 4 of the power management chip 21. Pin 5 of the power management chip 21 is connected to the positive pole of a 22uF C3 capacitor 22. The negative pole of the C3 capacitor 22 is connected to the ground. Pin 5 of the power management chip 21 is connected to pin 2 of the operational amplifier operational amplifier chip 10. Pin 8 of the power management chip 21 is connected to a 5V power supply. The 5V capacitor is connected to the positive pole of a D2 diode 23. The negative pole of the D2 diode 23 is connected to the positive pole of the D3 diode 24. The negative pole of the D3 diode 24 is connected to pin 6 of the operational amplifier chip 10.

[0048] The above has described the embodiments of the present application. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those of ordinary skill in the art in the technical field without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technologies in the market, or to enable other ordinary technical personnel in the technical field to understand the disclosed embodiments herein.

Claims

1. A feedback circuit for improving the measurement accuracy of a strain sensor, characterized in that: include: Power supply circuit, operational amplifier chip and filter circuit; The power supply circuit is electrically connected to the operational amplifier chip to supply power to the operational amplifier chip; The input end of the filter circuit is electrically connected to the operational amplifier chip, and the output end is suitable for connecting to the reference voltage electrical end of the AD chip to avoid overshoot; The power supply circuit includes: a power management chip, a C3 capacitor, a C5 capacitor, a C7 capacitor, a C6 capacitor, a C4 capacitor and a D3 diode, wherein the 2nd pin of the power management chip is electrically connected to the negative electrode of the C5 capacitor, the positive electrode of the C5 capacitor is electrically connected to the positive electrode of the D3 diode, the negative electrode of the D3 diode is connected to the 6th pin of the power management chip, the positive electrode of the D3 diode is connected to the negative electrode of the 100pF C5 capacitor, the positive electrode of the C7 capacitor is connected to the 2nd pin of the operational amplifier chip, the negative electrode of the D3 is also connected to the positive electrode of the 22uF C6 capacitor, and the negative electrode of the C6 capacitor is connected to the Ground, pin 2 of the power management chip is simultaneously connected to the positive electrode of the 22uF C4 capacitor, the negative electrode of the C4 capacitor is connected to pin 4 of the power management chip, pin 5 of the power management chip is connected to the positive electrode of the 22uF C3 capacitor, the negative electrode of the C3 capacitor is connected to ground, pin 5 of the power management chip is connected to pin 2 of the operational amplifier chip, pin 8 of the power management chip is connected to a 5V power supply, a 5V capacitor is connected to the positive electrode of the D2 diode, the negative electrode of the D2 diode is connected to the positive electrode of the D3 diode 24, and the negative electrode of the D3 diode is connected to pin 6 of the operational amplifier chip; It also includes an R13 resistor and an R9 resistor, wherein the R13 resistor and the R9 resistor are short-circuited and electrically connected to the negative end of the reference voltage of the AD chip for signal processing, and the reference voltage can enable the AD chip to convert an analog signal into a digital signal.

2. The feedback circuit for improving the measurement accuracy of a strain sensor according to claim 1, characterized in that: Pin 1 and pin 3 of the operational amplifier chip are suitable for being electrically connected to the feedback end of the sensor.

3. The feedback circuit for improving the measurement accuracy of a strain sensor according to claim 1, characterized in that: It also includes resistors R9 and R12; Pins 4 and 5 of the operational amplifier chip are short-circuited, electrically connected to the R9 resistor and the R12 resistor, and participate in signal regulation.

4. The feedback circuit for improving the measurement accuracy of a strain sensor according to claim 3, characterized in that: Also includes: R10 resistor and R8 resistor; The 7th pin and the 8th pin of the operational amplifier chip are short-circuited and electrically connected to the R10 resistor and the R8 resistor to process and transmit the signal.

5. The feedback circuit for improving the measurement accuracy of a strain sensor according to claim 4, characterized in that: The R10 resistor is electrically connected to the R11 resistor, and the R8 resistor is short-circuited with the R11 resistor and electrically connected to the positive terminal of the reference voltage of the AD chip to ensure the circuit function.

6. The feedback circuit for improving the measurement accuracy of a strain sensor according to claim 5, characterized in that: Also includes: R13 resistor, D7 diode, D6 diode, D5 diode and D4 diode; The R12 resistor is electrically connected to the R13 resistor and the cathode of the D7 diode, the anode of the D7 diode is electrically connected to the cathode of the D6 diode, the anode of the D6 diode is electrically connected to the cathode of the D5 diode, the anode of the D5 diode is electrically connected to the cathode of the D4 diode, and the anode of the D4 diode is electrically connected to the R10 resistor and the R11 resistor, respectively.

7. The feedback circuit for improving the measurement accuracy of a strain sensor according to claim 1, characterized in that: Also includes: C7 capacitor; The positive electrode of the D3 diode is electrically connected to the negative electrode of the C7 capacitor, and the positive electrode of the C7 capacitor is electrically connected to pin 2 of the operational amplifier chip.

8. The feedback circuit for improving the measurement accuracy of a strain sensor according to claim 7, characterized in that: Also includes the D2 diode and power supply; The 8 pins of the power management chip are electrically connected to the power supply, and are electrically connected to the operational amplifier chip through the D2 diode and the D3 diode.

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