A dual-power full-bridge strain amplifier circuit

Abstract

The present application discloses a dual-power full-bridge strain amplification circuit, including: a linear voltage-regulated power supply module, a bridge positive excitation voltage amplification circuit module, a bridge negative excitation voltage amplification circuit module, a full-bridge strain gauge module, a bias adjustment module, and a strain gauge output voltage amplification circuit module; the linear voltage-regulated power supply module is respectively connected to the bridge positive excitation voltage amplification circuit module and the bridge negative excitation voltage amplification circuit module; the bridge positive excitation voltage amplification circuit module and the bridge negative excitation voltage amplification circuit module are also connected to the full-bridge strain gauge module; the bias adjustment module is respectively connected to the bias adjustment module and the strain gauge output voltage amplification circuit module. The present application realizes stable amplification and accurate measurement of the strain gauge output signal; at the same time, the circuit of the present application also has functions such as temperature compensation, loop compensation, and adjustable bias voltage, which further improves the measurement accuracy and circuit compatibility.

Description

Technical Field

[0001] The present application relates to the field of circuit technology, and in particular to a dual-power supply full-bridge strain amplifier circuit. Background Art

[0002] Many precision sensors use a Wheatstone bridge circuit configuration. When external force or pressure causes the object to be measured to deform, the resistance of the strain gauge in the bridge changes, causing the balance of the bridge to be broken, and a weak voltage signal (usually at the millivolt level) proportional to the strain is output. This signal is weak and easily interfered by noise. Therefore, extremely high requirements are placed on the design of the amplifier circuit. Early amplifier circuit designs mainly relied on discrete components. This design method was limited by factors such as circuit temperature drift and input bias current, resulting in relatively poor measurement linearity and accuracy.

[0003] Although the current full-bridge circuit has higher sensitivity than the single strain gauge or half-bridge circuit, the existing full-bridge strain gauge technology still has some defects in practical applications. First, in terms of the bridge excitation voltage, if it is directly provided by an external power supply (such as a switching power supply DC / DC or AC / DC), it may introduce ripple noise of the power supply, which will have an adverse effect on the weak strain gauge output signal. Secondly, the two-way excitation voltage amplifier circuit often lacks loop compensation, resulting in loop instability, which in turn makes the weak bridge output voltage unstable, which not only affects the accuracy of the measurement results, but also reduces the stability and reliability of the system. In addition, for the bridge composed of strain gauges of different resistance values, the bridge output voltage circuit lacks the function of adjustable bias voltage, resulting in limited circuit compatibility. Summary of the invention

[0004] The main purpose of the present application is to overcome the shortcomings and deficiencies of the prior art and to provide a dual-power full-bridge strain amplifier circuit. The circuit in the present application achieves stable amplification and precise measurement of the strain gauge output signal by adopting a linear voltage-regulated power supply module, a bridge positive excitation voltage amplifier circuit module, a bridge negative excitation voltage amplifier circuit module, a full-bridge strain gauge module, a bias adjustment module, and a strain gauge output voltage amplifier circuit module. At the same time, the circuit also has functions such as temperature compensation, loop compensation, and adjustable bias voltage, which further improves the measurement accuracy and circuit compatibility.

[0005] In order to achieve the above objectives, this application adopts the following technical solutions:

[0006] A dual-power full-bridge strain amplifier circuit, comprising: a linear voltage-stabilized power supply module, a bridge positive excitation voltage amplifier circuit module, a bridge negative excitation voltage amplifier circuit module, a full-bridge strain gauge module, a bias adjustment module, and a strain gauge output voltage amplifier circuit module;

[0007] Among them, the first end of the linear voltage-regulated power supply module is connected to the first end of the bridge positive excitation voltage amplifier circuit module, and the second end of the linear voltage-regulated power supply module is connected to the first end of the bridge negative excitation voltage amplifier circuit module; the second end of the bridge positive excitation voltage amplifier circuit module is connected to the first end of the full-bridge strain gauge module; the second end of the bridge negative excitation voltage amplifier circuit module is connected to the second end of the full-bridge strain gauge module; the first end of the bias adjustment module is connected to the first end of the full-bridge strain gauge module, the second end of the bias adjustment module is connected to the second end of the full-bridge strain gauge module, and the third end of the bias adjustment module is connected to the first end of the strain gauge output voltage amplifier circuit module; the second end of the strain gauge output voltage amplifier circuit module is connected to the first end of the full-bridge strain gauge module, and the third end of the strain gauge output voltage amplifier circuit module is connected to the second end of the full-bridge strain gauge module.

[0008] As a preferred technical solution, it also includes an external constant DC power supply, which provides a positive voltage V+ and a negative voltage V- to the full-bridge strain amplifier circuit.

[0009] As a preferred technical solution, the constant DC power supply is connected to the third end of the linear voltage-regulated power supply module;

[0010] The linear voltage-stabilized power supply module includes a linear voltage-stabilized chip U1, and the linear voltage-stabilized chip U1 converts the positive voltage V+ into a 5V voltage or a 2.5V voltage.

[0011] As a preferred technical solution, the bridge positive excitation voltage amplification circuit module provides a positive excitation voltage to the full-bridge strain gauge module.

[0012] As a preferred technical solution, the bridge positive excitation voltage amplification circuit module includes an operational amplifier U2B, a capacitor C3, a capacitor C4, a resistor R5, a resistor R6 and a resistor R7;

[0013] The first end of the operational amplifier U2B is respectively connected to the first end of the resistor R5, the first end of the capacitor C4, and the first end of the resistor R6; the second end of the resistor R5 is connected to the first end of the capacitor C3;

[0014] The second terminal of the operational amplifier U2B is connected to the negative voltage V-;

[0015] The third terminal of the operational amplifier U2B is connected to the positive voltage V+;

[0016] The fourth terminal of the operational amplifier U2B is connected to the linear voltage regulated power supply module;

[0017] The fifth end of the operational amplifier U2B is respectively connected to the second end of the capacitor C3, the second end of the capacitor C4, the second end of the resistor R6, and the first end of the resistor R7; the second end of the resistor R7 is grounded.

[0018] As a preferred technical solution, the bridge negative excitation voltage amplification circuit module provides a negative excitation voltage to the full-bridge strain gauge module.

[0019] As a preferred technical solution, the bridge negative excitation voltage amplification circuit module includes an operational amplifier U2A, a capacitor C5, a capacitor C6, a capacitor C7, a resistor R8, a resistor R9 and a resistor R10;

[0020] The first end of the operational amplifier U2A is respectively connected to the first end of the resistor R8, the first end of the capacitor C6, and the first end of the resistor R10; the second end of the resistor R8 is connected to the first end of the capacitor C5;

[0021] The fourth terminal of the operational amplifier U2A is grounded;

[0022] The fifth end of the operational amplifier U2A is respectively connected to the second end of the capacitor C5, the second end of the capacitor C6, the first end of the resistor R9, and the second end of the resistor R10; the second end of the resistor R9 is respectively connected to the first end of the capacitor C7 and the fourth end of the operational amplifier U2B; the second end of the capacitor C7 is grounded.

[0023] As a preferred technical solution, the full-bridge strain gauge module includes a variable resistor R1, a variable resistor R2, a variable resistor R3 and a variable resistor R4;

[0024] Among them, the first end of the variable resistor R1 is respectively connected to the first end of the operational amplifier U2B and the first end of the variable resistor R4; the second end of the variable resistor R1 is connected to the first end of the variable resistor R2; the second end of the variable resistor R4 is connected to the first end of the resistor R3; the second end of the resistor R3 is respectively connected to the second end of the variable resistor R2 and the first end of the operational amplifier U2A.

[0025] As a preferred technical solution, the bias adjustment module includes an adjustable potentiometer R11 and a resistor R12;

[0026] Wherein, the first end of the adjustable potentiometer R11 is respectively connected to the first end of the variable resistor R1, the first end of the variable resistor R4, and the first end of the operational amplifier U2B;

[0027] The second end of the adjustable potentiometer R11 is respectively connected to the second end of the variable resistor R2, the second end of the variable resistor R3, and the first end of the operational amplifier U2A;

[0028] The third end of the adjustable potentiometer R11 is connected to the first end of the resistor R12.

[0029] As a preferred technical solution, the strain gauge output voltage amplification circuit module includes: an operational amplifier U3, a capacitor C8, a capacitor C9, a resistor R13, a resistor R14, a resistor R16 and an adjustable potentiometer R15;

[0030] The first end of the operational amplifier U3 is connected to the first end of the resistor R13 and the first end of the capacitor C8 respectively; the second end of the resistor R13 is connected to the first end of the adjustable potentiometer R15 and the first end of the capacitor C9 respectively; the second end of the adjustable potentiometer R15 is connected to the first end of the resistor R16 respectively; the second end of the resistor R16 is grounded; the third end of the adjustable potentiometer R15 is connected to the first end of the resistor R14;

[0031] The second terminal of the operational amplifier U3 is connected to the negative voltage V-;

[0032] The third terminal of the operational amplifier U3 is connected to the positive voltage V+;

[0033] The fourth end of the operational amplifier U3 is respectively connected to the second end of the resistor R12, the first end of the variable resistor R2, and the second end of the variable resistor R1;

[0034] The fifth end of the operational amplifier U3 is connected to the first end of the variable resistor R3 , the second end of the capacitor C8 , the second end of the capacitor C9 , and the second end of the resistor R14 , respectively.

[0035] In summary, compared with the prior art, the present application has at least the following advantages and beneficial effects:

[0036] The present application provides a dual-power full-bridge strain amplifier circuit, which adopts a full-bridge strain gauge configuration. Compared with a single strain gauge or a half-bridge circuit, it has higher sensitivity and can more accurately reflect the deformation signal of the object being measured. At the same time, there is no inherent nonlinearity in the full-bridge output, thereby ensuring the linearity of the measurement. In addition, since the effects of temperature on each strain gauge can offset each other, the circuit can also effectively compensate for the errors caused by temperature changes, further improving the accuracy of the measurement. At the same time, the two-way excitation voltage amplifier circuit in the present application adopts proportional integral loop compensation technology, which effectively avoids voltage fluctuations (noise) caused by loop instability (such as system oscillation), thereby ensuring the stability of the bridge output voltage. In addition, the bridge output voltage amplifier circuit module in the present application has an adjustable bias voltage function, which enables the circuit to adapt to strain gauges of various resistance values, thereby enhancing the compatibility and application range of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0038] Figure 1 A block diagram of a dual-power full-bridge strain amplifier circuit provided in accordance with an embodiment of the present application.

[0039] Figure 2 A circuit schematic diagram of a dual-power full-bridge strain amplifier circuit provided in one embodiment of the present application. DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

[0041] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0042] See also Figure 1 , the present application provides a dual-power full-bridge strain amplifier circuit, including: a linear voltage-regulated power supply module, a bridge positive excitation voltage amplifier circuit module, a bridge negative excitation voltage amplifier circuit module, a full-bridge strain gauge module, a bias adjustment module, and a strain gauge output voltage amplifier circuit module;

[0043] Among them, the first end of the linear voltage-regulated power supply module is connected to the first end of the bridge positive excitation voltage amplifier circuit module, and the second end of the linear voltage-regulated power supply module is connected to the first end of the bridge negative excitation voltage amplifier circuit module; the second end of the bridge positive excitation voltage amplifier circuit module is connected to the first end of the full-bridge strain gauge module; the second end of the bridge negative excitation voltage amplifier circuit module is connected to the second end of the full-bridge strain gauge module; the first end of the bias adjustment module is connected to the first end of the full-bridge strain gauge module, the second end of the bias adjustment module is connected to the second end of the full-bridge strain gauge module, and the third end of the bias adjustment module is connected to the first end of the strain gauge output voltage amplifier circuit module; the second end of the strain gauge output voltage amplifier circuit module is connected to the first end of the full-bridge strain gauge module, and the third end of the strain gauge output voltage amplifier circuit module is connected to the second end of the full-bridge strain gauge module.

[0044] As one implementation manner, it also includes an external constant DC power supply, which provides a positive voltage V+ and a negative voltage V- to the full-bridge strain amplifier circuit.

[0045] Wherein, the constant DC power supply is connected to the third end of the linear voltage-regulated power supply module.

[0046] See also Figure 2 , the linear voltage stabilizing power supply module includes a linear voltage stabilizing chip U1, and the linear voltage stabilizing chip U1 converts the positive voltage V+ into a 5V voltage or a 2.5V voltage. It can be seen that the dual power supply design of the present application and the application of the linear voltage stabilizing power supply module further improve the flexibility and stability of the circuit; that is, the linear voltage stabilizing chip can convert the positive voltage V+ provided by the external constant DC power supply into a stable 5V or 2.5V voltage, so for strain gauges with different resistance values, the excitation voltages at both ends can have different options; at the same time, it provides a reliable power supply guarantee for the circuit.

[0047] As one implementation manner, the bridge positive excitation voltage amplification circuit module provides a positive excitation voltage to the full-bridge strain gauge module.

[0048] As one implementation method, the bridge positive excitation voltage amplification circuit module includes an operational amplifier U2B, a capacitor C3, a capacitor C4, a resistor R5, a resistor R6 and a resistor R7;

[0049] The first end of the operational amplifier U2B is respectively connected to the first end of the resistor R5, the first end of the capacitor C4, and the first end of the resistor R6; the second end of the resistor R5 is connected to the first end of the capacitor C3;

[0050] The second terminal of the operational amplifier U2B is connected to the negative voltage V-;

[0051] The third terminal of the operational amplifier U2B is connected to the positive voltage V+;

[0052] The fourth terminal of the operational amplifier U2B is connected to the linear voltage regulated power supply module;

[0053] The fifth end of the operational amplifier U2B is respectively connected to the second end of the capacitor C3, the second end of the capacitor C4, the second end of the resistor R6, and the first end of the resistor R7; the second end of the resistor R7 is grounded.

[0054] Specifically, the operational amplifier U2B and the capacitor C3, the capacitor C4, the resistor R5, the resistor R6 and the resistor R7 form a common-phase proportional integral amplifier circuit. The output voltage of the linear voltage regulator chip U1 is amplified by the operational amplifier U2B to provide a positive excitation voltage to the full bridge.

[0055] As one implementation manner, the bridge negative excitation voltage amplification circuit module provides a negative excitation voltage to the full-bridge strain gauge module.

[0056] As one implementation method, the bridge negative excitation voltage amplifier circuit module includes an operational amplifier U2A, a capacitor C5, a capacitor C6, a capacitor C7, a resistor R8, a resistor R9 and a resistor R10;

[0057] The first end of the operational amplifier U2A is respectively connected to the first end of the resistor R8, the first end of the capacitor C6, and the first end of the resistor R10; the second end of the resistor R8 is connected to the first end of the capacitor C5;

[0058] The fourth terminal of the operational amplifier U2A is grounded;

[0059] The fifth end of the operational amplifier U2A is respectively connected to the second end of the capacitor C5, the second end of the capacitor C6, the first end of the resistor R9, and the second end of the resistor R10; the second end of the resistor R9 is respectively connected to the first end of the capacitor C7 and the fourth end of the operational amplifier U2B; the second end of the capacitor C7 is grounded.

[0060] Specifically, the operational amplifier U2A and the capacitors C5, C6, C7, R8, R9 and R10 form an inverting proportional integral amplifier circuit. The output voltage of the linear voltage regulator chip U1 is amplified by U2A to provide a negative excitation voltage to the full bridge.

[0061] The capacitor C4 in the bridge positive excitation voltage amplifier circuit module and the capacitor C6 in the bridge negative excitation voltage amplifier circuit module of the present application serve as feedback capacitors and can form a low-pass filter together with resistors (such as R5, R6, etc.). This low-pass filter can effectively suppress high-frequency noise and interference signals, allowing only lower frequency signals to pass through, while filtering out high-frequency signals (such as electromagnetic interference or other noise). For strain gauge signals, the signal frequency is usually low, so filtering out high-frequency noise is very helpful for improving signal quality. In addition, the capacitors C4 and C6 in the feedback loop are used to compensate for the phase to avoid self-oscillation of the operational amplifier caused by high-frequency phase lag. This phase compensation can improve the stability of the amplifier circuit and ensure that the operational amplifier will not cause unstable oscillation due to excessive high-frequency signals.

[0062] In addition, if the effect of capacitor C4 is not considered, the transfer function of the amplifier loop of operational amplifier U2B is (1), and the amplification ratio and amplitude-frequency-phase-frequency characteristics can be obtained from the transfer function. Similarly, if the effect of C6 is not considered, the transfer function of the amplifier loop of U2A is (2), and the amplification ratio and amplitude-frequency-phase-frequency characteristics can be obtained from the transfer function. After adding C4 and C6, the transfer function can be derived as (3), and the loop has proportional integral and first-order lag functions.

[0063] H(s)=1+(R5R6SC+R6) / R7[(R5+R6)SC+1] (1)

[0064] H(s)=-(SC(R8 ^ R9)+R9) / (R10(R8+R9)SC+R10) (2)

[0065]

[0066] More specifically, the operational amplifier U2A and operational amplifier U2B of the present application are FET (field effect transistor) operational amplifiers, and the input stage uses field effect transistors, which have the advantages of high slew rate, low noise and low power consumption.

[0067] As one implementation mode, the full-bridge strain gauge module includes a variable resistor R1, a variable resistor R2, a variable resistor R3 and a variable resistor R4;

[0068] Among them, the first end of the variable resistor R1 is respectively connected to the first end of the operational amplifier U2B and the first end of the variable resistor R4; the second end of the variable resistor R1 is connected to the first end of the variable resistor R2; the second end of the variable resistor R4 is connected to the first end of the resistor R3; the second end of the resistor R3 is respectively connected to the second end of the variable resistor R2 and the first end of the operational amplifier U2A.

[0069] As one implementation mode, the bias adjustment module includes an adjustable potentiometer R11 and a resistor R12;

[0070] Wherein, the first end of the adjustable potentiometer R11 is respectively connected to the first end of the variable resistor R1, the first end of the variable resistor R4, and the first end of the operational amplifier U2B;

[0071] The second end of the adjustable potentiometer R11 is respectively connected to the second end of the variable resistor R2, the second end of the variable resistor R3, and the first end of the operational amplifier U2A;

[0072] The third end of the adjustable potentiometer R11 is connected to the first end of the resistor R12.

[0073] As one implementation method, the strain gauge output voltage amplification circuit module includes: an operational amplifier U3, a capacitor C8, a capacitor C9, a resistor R13, a resistor R14, a resistor R16 and an adjustable potentiometer R15;

[0074] The first end of the operational amplifier U3 is connected to the first end of the resistor R13 and the first end of the capacitor C8 respectively; the second end of the resistor R13 is connected to the first end of the adjustable potentiometer R15 and the first end of the capacitor C9 respectively; the second end of the adjustable potentiometer R15 is connected to the first end of the resistor R16 respectively; the second end of the resistor R16 is grounded; the third end of the adjustable potentiometer R15 is connected to the first end of the resistor R14;

[0075] The second terminal of the operational amplifier U3 is connected to the negative voltage V-;

[0076] The third terminal of the operational amplifier U3 is connected to the positive voltage V+;

[0077] The fourth end of the operational amplifier U3 is respectively connected to the second end of the resistor R12, the first end of the variable resistor R2, and the second end of the variable resistor R1;

[0078] The fifth end of the operational amplifier U3 is connected to the first end of the variable resistor R3 , the second end of the capacitor C8 , the second end of the capacitor C9 , and the second end of the resistor R14 , respectively.

[0079] Furthermore, the adjustable potentiometer R11 in the bias adjustment module adjusts the input bias voltage of the operational amplifier U3, that is, adjusts the output voltage reference when the bridge is in a balanced state. It can be seen that the bias adjustment module in the present application has an adjustable potentiometer, which can adjust the reference output voltage for strain gauges (loads) with different resistance values, enhances the compatibility of the circuit, and enables the circuit to be applicable to a variety of different strain gauge combinations and measurement requirements.

[0080] The adjustable potentiometer R15 in the strain gauge output voltage amplification circuit module can fine-tune the amplification ratio of the operational amplifier U3.

[0081] Furthermore, the operational amplifier U3 amplifies the weak differential signal output by the full-bridge, and the resistor R12, the full-bridge variable equivalent resistor, R14, R15 and R16 determine the amplification ratio of the differential amplifier circuit.

[0082] The capacitors C8 and C9 in the strain gauge output voltage amplifier circuit module of the present application and the corresponding feedback resistors (R13, R14) cooperate to form a low-pass filter for filtering high-frequency noise and interference signals. During the amplification process, when a weak signal is amplified, high-frequency noise may introduce interference and affect the accuracy of the amplified signal. At the same time, as a compensation capacitor, high-frequency oscillations can be suppressed. By performing phase compensation on the feedback signal, it is ensured that the operational amplifier still maintains stable operation under high gain conditions, avoiding the occurrence of oscillations or parasitic oscillations. Similarly, the transfer function of U3 can be derived to obtain the amplification ratio and amplitude-frequency-phase-frequency characteristics.

[0083] The above embodiments are preferred implementation modes of the present application, but the implementation modes of the present application are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present application should be equivalent replacement methods and are included in the protection scope of the present application.

Claims

1. A dual-power full-bridge strain amplifier circuit, characterized in that: include: Linear voltage-regulated power supply module, bridge positive excitation voltage amplifier circuit module, bridge negative excitation voltage amplifier circuit module, full-bridge strain gauge module, bias adjustment module and strain gauge output voltage amplifier circuit module; Among them, the first end of the linear voltage-regulated power supply module is connected to the first end of the bridge positive excitation voltage amplifier circuit module, and the second end of the linear voltage-regulated power supply module is connected to the first end of the bridge negative excitation voltage amplifier circuit module; the second end of the bridge positive excitation voltage amplifier circuit module is connected to the first end of the full-bridge strain gauge module; the second end of the bridge negative excitation voltage amplifier circuit module is connected to the second end of the full-bridge strain gauge module; the first end of the bias adjustment module is connected to the first end of the full-bridge strain gauge module, the second end of the bias adjustment module is connected to the second end of the full-bridge strain gauge module, and the third end of the bias adjustment module is connected to the first end of the strain gauge output voltage amplifier circuit module; the second end of the strain gauge output voltage amplifier circuit module is connected to the first end of the full-bridge strain gauge module, and the third end of the strain gauge output voltage amplifier circuit module is connected to the second end of the full-bridge strain gauge module.

2. According to claim 1, a dual-power full-bridge strain amplifier circuit is characterized in that: It also includes an external constant DC power supply, which provides a positive voltage V+ and a negative voltage V- to the full-bridge strain amplifier circuit.

3. The dual-power full-bridge strain amplifier circuit according to claim 2, characterized in that: The constant DC power supply is connected to the third end of the linear voltage-regulated power supply module; The linear voltage-stabilized power supply module includes a linear voltage-stabilized chip U1, and the linear voltage-stabilized chip U1 converts the positive voltage V+ into a 5V voltage or a 2.5V voltage.

4. The dual-power full-bridge strain amplifier circuit according to claim 1, characterized in that: The bridge positive excitation voltage amplifying circuit module provides a positive excitation voltage to the full-bridge strain gauge module.

5. The dual-power full-bridge strain amplifier circuit according to claim 1, characterized in that: The bridge positive excitation voltage amplification circuit module includes an operational amplifier U2B, a capacitor C3, a capacitor C4, a resistor R5, a resistor R6 and a resistor R7; The first end of the operational amplifier U2B is respectively connected to the first end of the resistor R5, the first end of the capacitor C4, and the first end of the resistor R6; the second end of the resistor R5 is connected to the first end of the capacitor C3; The second terminal of the operational amplifier U2B is connected to the negative voltage V-; The third terminal of the operational amplifier U2B is connected to the positive voltage V+; The fourth terminal of the operational amplifier U2B is connected to the linear voltage regulated power supply module; The fifth end of the operational amplifier U2B is respectively connected to the second end of the capacitor C3, the second end of the capacitor C4, the second end of the resistor R6, and the first end of the resistor R7; the second end of the resistor R7 is grounded.

6. The dual-power full-bridge strain amplifier circuit according to claim 1, characterized in that: The bridge negative excitation voltage amplifying circuit module provides a negative excitation voltage to the full-bridge strain gauge module.

7. The dual-power full-bridge strain amplifier circuit according to claim 5, characterized in that: The bridge negative excitation voltage amplification circuit module includes an operational amplifier U2A, a capacitor C5, a capacitor C6, a capacitor C7, a resistor R8, a resistor R9 and a resistor R10; The first end of the operational amplifier U2A is respectively connected to the first end of the resistor R8, the first end of the capacitor C6, and the first end of the resistor R10; the second end of the resistor R8 is connected to the first end of the capacitor C5; The fourth terminal of the operational amplifier U2A is grounded; The fifth end of the operational amplifier U2A is respectively connected to the second end of the capacitor C5, the second end of the capacitor C6, the first end of the resistor R9, and the second end of the resistor R10; the second end of the resistor R9 is respectively connected to the first end of the capacitor C7 and the fourth end of the operational amplifier U2B; the second end of the capacitor C7 is grounded.

8. The dual-power full-bridge strain amplifier circuit according to claim 7, characterized in that: The full-bridge strain gauge module includes a variable resistor R1, a variable resistor R2, a variable resistor R3 and a variable resistor R4; Among them, the first end of the variable resistor R1 is respectively connected to the first end of the operational amplifier U2B and the first end of the variable resistor R4; the second end of the variable resistor R1 is connected to the first end of the variable resistor R2; the second end of the variable resistor R4 is connected to the first end of the resistor R3; the second end of the resistor R3 is respectively connected to the second end of the variable resistor R2 and the first end of the operational amplifier U2A.

9. The dual-power full-bridge strain amplifier circuit according to claim 8, characterized in that: The bias adjustment module includes an adjustable potentiometer R11 and a resistor R12; Wherein, the first end of the adjustable potentiometer R11 is respectively connected to the first end of the variable resistor R1, the first end of the variable resistor R4, and the first end of the operational amplifier U2B; The second end of the adjustable potentiometer R11 is respectively connected to the second end of the variable resistor R2, the second end of the variable resistor R3, and the first end of the operational amplifier U2A; The third end of the adjustable potentiometer R11 is connected to the first end of the resistor R12.

10. The dual-power full-bridge strain amplifier circuit according to claim 9, characterized in that: The strain gauge output voltage amplification circuit module includes: an operational amplifier U3, a capacitor C8, a capacitor C9, a resistor R13, a resistor R14, a resistor R16 and an adjustable potentiometer R15; The first end of the operational amplifier U3 is connected to the first end of the resistor R13 and the first end of the capacitor C8 respectively; the second end of the resistor R13 is connected to the first end of the adjustable potentiometer R15 and the first end of the capacitor C9 respectively; the second end of the adjustable potentiometer R15 is connected to the first end of the resistor R16 respectively; the second end of the resistor R16 is grounded; the third end of the adjustable potentiometer R15 is connected to the first end of the resistor R14; The second terminal of the operational amplifier U3 is connected to the negative voltage V-; The third terminal of the operational amplifier U3 is connected to the positive voltage V+; The fourth end of the operational amplifier U3 is respectively connected to the second end of the resistor R12, the first end of the variable resistor R2, and the second end of the variable resistor R1; The fifth end of the operational amplifier U3 is connected to the first end of the variable resistor R3 , the second end of the capacitor C8 , the second end of the capacitor C9 , and the second end of the resistor R14 , respectively.

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