Full-bridge strain gauge bias voltage adjusting circuit
By using a full-bridge strain gauge bias voltage adjustment circuit, differential amplification and compensation modules are employed to cancel the bias voltage, thus solving the measurement error problem caused by asymmetrical strain gauge bonding and improving the sensor's measurement accuracy and range.
Patent Information
- Application Number
- CN202411177675.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-26
- Publication Date
- 2025-10-31
AI Technical Summary
The bias voltage caused by asymmetrical strain gauge bonding in full-bridge strain gauge sensors affects the measurement accuracy and range, especially in high-precision measurement applications.
A full-bridge strain gauge bias voltage adjustment circuit is adopted. Through a differential amplification module and a compensation module, the bias voltage is offset by the compensation voltage to achieve zeroing of the sensor signal.
It effectively counteracts the influence of bias voltage, ensuring that the sensor output signal reflects the actual measured physical quantity, thereby improving measurement accuracy and extending the measurement range.
Smart Images
Figure CN120872083A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of detection technology, and in particular to a full-bridge strain gauge bias voltage adjustment circuit. Background Technology
[0002] In the field of sensor technology, full-bridge strain gauge sensors are widely used to measure various physical quantities such as pressure and position due to their high sensitivity and stability. However, these sensors often face a key problem in practical applications: due to asymmetrical strain gauge bonding, the sensor signal itself will have a large bias, forming a bias voltage. This bias voltage not only reduces the measurement accuracy of the sensor but also limits its measurement range, thus affecting the overall performance of the sensor.
[0003] Specifically, strain gauge sensors work by measuring the change in resistance of a strain gauge under stress to detect corresponding physical quantities. However, when the strain gauge is unevenly bonded or other manufacturing errors exist, the sensor will output a non-zero initial signal, i.e., a bias voltage, even under no-load conditions. This bias voltage will be superimposed on the actual measurement signal, causing deviations in the measurement results, especially noticeable in low-range or high-precision measurement applications.
[0004] In summary, due to the presence of bias voltage, the output signal of the sensor in the existing technology contains an error component that is not part of the measurement signal. This affects the accuracy of the measurement results, and the presence of bias voltage reduces the effective measurement range of the sensor. The impact of bias voltage is particularly significant in applications requiring high-precision measurement. Summary of the Invention
[0005] This application provides a full-bridge strain gauge bias voltage adjustment circuit to improve the technical problem in related technologies where the output signal of the sensor contains an error component that is not a measurement signal.
[0006] To achieve the above objectives, the embodiments of this application adopt the following technical solutions: This application provides a full-bridge strain gauge bias voltage adjustment circuit applied to a full-bridge circuit. The full-bridge circuit outputs a first induced voltage at its first output terminal and a second induced voltage at its second output terminal. The adjustment circuit includes: a differential amplifier module, whose first input terminal is coupled to the first output terminal of the full-bridge circuit, and whose second input terminal is coupled to the second output terminal of the full-bridge circuit; a reference terminal of the differential amplifier module for receiving a first compensation voltage; and an output of a first differential voltage based on the first compensation voltage, the first induced voltage, and the second induced voltage; and a sampling module, whose first input terminal is coupled to the output terminal of the differential amplifier module, and whose second input terminal receives the second compensation voltage; the sampling module for outputting a second differential voltage based on the first differential voltage and the second compensation voltage. The adjustment circuit is used to compensate the second differential voltage based on the first compensation voltage and / or the second compensation voltage.
[0007] In one possible implementation, the adjustment circuit further includes a first compensation module coupled to the differential amplifier module for providing the first compensation voltage.
[0008] In one possible implementation, the first compensation module includes a first digital-to-analog converter (DAC) unit and a first voltage follower unit. The DAC unit is used to provide a first voltage. The voltage follower unit is coupled to the DAC unit and is also coupled to a reference terminal of the differential amplifier module. The voltage follower unit is used to provide the first compensation voltage to the differential amplifier module according to the first voltage.
[0009] In one possible implementation, the second input terminal of the sampling module is coupled to the first reference voltage terminal, which is used to provide the second compensation voltage. The adjustment circuit adjusts the first compensation voltage by controlling the first digital-to-analog conversion unit to compensate for the second differential voltage.
[0010] In one possible implementation, the adjustment circuit further includes a second compensation module coupled to the second input terminal of the sampling module, for providing the second compensation voltage.
[0011] In one possible implementation, the second compensation module includes a second digital-to-analog converter (DAC) coupled to a second input terminal of the sampling module, and the DAC is used to provide a second compensation voltage.
[0012] In one possible implementation, the adjustment circuit further includes a second voltage follower unit coupled to a second reference voltage terminal and also coupled to a reference terminal of the differential amplifier module. The second reference voltage terminal is used to provide a second voltage, and the second voltage follower unit is used to provide a second compensation voltage to the differential amplifier module according to the second voltage. The adjustment circuit adjusts the second compensation voltage by controlling the second digital-to-analog converter unit to compensate for the second differential voltage.
[0013] In one possible implementation, the adjustment circuit includes: a first compensation module, which includes a first digital-to-analog converter (DAC) unit and a first voltage follower unit. The DAC unit provides a first voltage, and the voltage follower unit is coupled to the DAC unit and further coupled to the differential amplifier module. The voltage follower unit provides a first compensation voltage to the differential amplifier module based on the first voltage. A second compensation module includes a second DAC unit and a second voltage follower unit. The DAC unit provides a second voltage, and the voltage follower unit is coupled to the DAC unit and further coupled to a second input terminal of the sampling module. The voltage follower unit provides a second compensation voltage to the sampling module based on the second voltage. The adjustment circuit compensates for the second differential voltage using the first compensation voltage and the second compensation voltage.
[0014] In one possible implementation, the adjustment circuit further includes a filtering module coupled to the output terminal of the differential amplifier module and also coupled to the second input terminal of the sampling module. The filtering module is used to filter the first differential voltage.
[0015] In one possible implementation, the filtering module includes a low-pass filter unit coupled to the output of the differential amplifier module, and the low-pass filter unit is also coupled to the second input of the sampling module. Attached Figure Description
[0016] Figure 1 Schematic diagrams of the full-bridge circuit provided for some embodiments of this application; Figure 2 Schematic diagrams of the adjustment circuit provided for some embodiments of this application; Figure 3 Schematic diagrams of the adjustment circuit provided for other embodiments of this application; Figure 4Schematic diagrams of the adjustment circuit provided for other embodiments of this application; Figure 5 Schematic diagrams of the adjustment circuit provided for other embodiments of this application; Figure 6 Schematic diagrams of the adjustment circuit provided for other embodiments of this application; Figure 7 A schematic diagram of the adjustment circuit provided for some other embodiments of this application. Detailed Implementation
[0017] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.
[0018] In the following description, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.
[0019] Furthermore, in this application, directional terms such as "upper," "lower," "left," and "right" may be defined relative to the orientation of the components shown in the accompanying drawings. It should be understood that these directional terms can be relative concepts, used for relative description and clarification, and may change accordingly depending on the orientation of the components in the accompanying drawings.
[0020] In this application, unless otherwise expressly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection through an intermediate medium. Furthermore, the term "electrical connection" can refer to the manner in which an electrical connection is used to achieve signal transmission.
[0021] As used herein, “about,” “approximately,” or “approximately” includes the stated value and a reference value within an acceptable range of deviation from the given value, wherein the acceptable range of deviation is determined by a person skilled in the art taking into account the measurement under discussion and the error associated with the measurement of the given quantity (i.e., the limitations of the measurement system).
[0022] In the embodiments of this application, the words "exemplarily" or "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplarily" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design solutions. Specifically, the use of the words "exemplarily" or "for example" is intended to present the relevant concepts in a specific manner.
[0023] In the field of sensor technology, full-bridge strain gauge sensors are widely used to measure various physical quantities such as pressure and position due to their high sensitivity and stability. However, these sensors often face a key problem in practical applications: due to asymmetrical strain gauge bonding, the sensor signal itself will have a large bias, forming a bias voltage. This bias voltage not only reduces the measurement accuracy of the sensor but also limits its measurement range, thus affecting the overall performance of the sensor.
[0024] Specifically, strain gauge sensors work by measuring the change in resistance of a strain gauge under stress to detect corresponding physical quantities. However, when the strain gauge is unevenly bonded or other manufacturing errors exist, the sensor will output a non-zero initial signal, i.e., a bias voltage, even under no-load conditions. This bias voltage will be superimposed on the actual measurement signal, causing deviations in the measurement results, especially noticeable in low-range or high-precision measurement applications.
[0025] In summary, due to the presence of bias voltage, the output signal of existing sensors contains an error component that is not part of the measured signal, which affects the accuracy of the measurement results. The presence of bias voltage reduces the effective measurement range of the sensor, especially in applications requiring high-precision measurements, where the impact of bias voltage is particularly significant. To reduce the influence of bias voltage, a complex calibration process is usually required, which not only increases operational complexity but also costs.
[0026] To address the aforementioned problems, this invention proposes a full-bridge strain gauge bias voltage adjustment circuit, which can achieve zero adjustment of the sensor bias voltage, thereby ensuring that the sensor output signal only reflects the actual measured physical quantity, thus improving the technical problem in related technologies where the sensor output signal contains error components that are not measured signals.
[0027] like Figure 1As shown, the full-bridge circuit 200 includes a first sensor L1, a second sensor L2, a third sensor L3, and a fourth sensor L4. The first sensor L1 and the second sensor L2 are connected in series to form a first sensor group, and the third sensor L3 and the fourth sensor L4 are connected in series to form a second sensor group. The first sensor group and the second sensor group are connected in parallel. The first common terminal of the parallel connection of the first and second sensor groups receives the power supply voltage VCC, and the second common terminal of the parallel connection of the first and second sensor groups is grounded. Under external load, the first output terminal of the full-bridge circuit 200 can output a first induced voltage Vp, and the second output terminal of the full-bridge circuit 200 can output a second induced voltage Vn.
[0028] like Figure 2 As shown, the adjustment circuit includes a differential amplifier module 10, a sampling module 30, and a first compensation module 40.
[0029] The first input terminal of the differential amplifier module 10 is coupled to the first output terminal of the full-bridge circuit 200, and the second input terminal of the differential amplifier module 10 is coupled to the second output terminal of the full-bridge circuit 200. The reference terminal of the differential amplifier module 10 is used to receive the first compensation voltage. The differential amplifier module 10 outputs a first differential voltage based on the first compensation voltage, the first induced voltage, and the second induced voltage.
[0030] For example, the differential amplifier module 10 can be an instrumentation amplifier. The first input terminal of the instrumentation amplifier is coupled to the first output terminal of the full-bridge circuit 200, and the second input terminal of the instrumentation amplifier is coupled to the second output terminal of the full-bridge circuit 200. The reference terminal of the instrumentation amplifier is used to receive the first compensation voltage. The instrumentation amplifier calculates and amplifies the difference between the first induced voltage and the second induced voltage, and outputs the amplified difference along with the first compensation voltage as the first differential voltage.
[0031] like Figure 3 As shown, the first compensation module 40 includes a first digital-to-analog converter 41 and a first voltage follower unit 42. The first digital-to-analog converter 41 is used to provide a first voltage. The first voltage follower unit 42 is coupled to the first digital-to-analog converter 41 and is also coupled to the reference terminal of the differential amplifier module 10. The first voltage follower unit 42 is used to provide a first compensation voltage to the differential amplifier module 10 according to the first voltage.
[0032] The first input terminal of the sampling module 30 is coupled to the output terminal of the differential amplifier module 10, and the second input terminal of the sampling module 30 is coupled to the first reference voltage terminal. The first reference voltage terminal is used to provide the second compensation voltage, and the sampling module 30 is used to output the second differential voltage according to the first differential voltage and the second compensation voltage.
[0033] For example, the sampling module 30 can be a digital-to-analog converter (DAC). The first input terminal of the DAC is coupled to the output terminal of the differential amplifier module 10, and the second input terminal of the DAC is coupled to a first reference voltage terminal. The DAC is used to output a second differential voltage based on the first differential voltage and the second compensation voltage. Figure 4 As shown, in some examples, the first reference voltage terminal can be the reference voltage terminal of the digital-to-analog converter itself.
[0034] When the strain gauge is manufactured normally, the first differential voltage, i.e., the voltage received at the first input terminal of the digital-to-analog converter, is: V adc_p =(Vp-Vn)*G+V dac1 Among them, V adc_p Vp is the voltage received at the first input terminal of the digital-to-analog converter, Vn is the first induced voltage, and V is the second induced voltage. dac1 Here, is the first compensation voltage, and G is the gain of the instrumentation amplifier.
[0035] However, when the strain gauges are unevenly bonded or other manufacturing errors exist, the sensor will also output a non-zero initial signal under no-load conditions. That is, the full-bridge circuit 200 will also output a bias voltage to the instrumentation amplifier. The instrumentation amplifier will also amplify and output this bias voltage. At this time, the signal received by the first differential voltage, i.e., the first input terminal of the digital-to-analog converter, is: V adc_p =(Vp-Vn)*G+V bias *G+V dac1 Among them, V adc_p Vp is the voltage received at the first input terminal of the digital-to-analog converter, Vn is the first induced voltage, and V is the second induced voltage. dac1 The first compensation voltage is V, G is the gain of the instrumentation amplifier, and V is the gain of the instrumentation amplifier. bias This is the bias voltage.
[0036] The second differential voltage output by the digital-to-analog converter is: V adc_p -V adc_n =(Vp-Vn)*G+V bias *G+V dac1 -V adc_ref Among them, V adc_ref This is the second compensation voltage.
[0037] When it is necessary to make the value of the second differential voltage the difference between the first induced voltage and the second induced voltage, the value of the first compensation voltage can be adjusted so that V dac1 = V adc_ref -Vbias *G, at this time: V adc_p -V adc_n =(Vp-Vn)*G When the sensor has no external load, i.e., Vp=0, Vn=0, Vadc_p=Vadc_n, the second differential voltage output by the digital-to-analog converter is 0, thus achieving zeroing of the bias voltage. Therefore, the adjustment circuit can compensate for the second differential voltage by adjusting the first compensation voltage to counteract the influence of the bias voltage.
[0038] In some embodiments, the adjustment circuit may further include a filter module 20, which is coupled to the output terminal of the differential amplifier module 10 and is also coupled to the second input terminal of the sampling module 30. The filter module 20 is used to filter the first differential voltage.
[0039] For example, the filtering module 20 may include a low-pass filter unit coupled to the output terminal of the differential amplifier module 10, and the low-pass filter unit is also coupled to the second input terminal of the sampling module 30.
[0040] like Figure 5 As shown, the adjustment circuit includes a differential amplifier module 10, a second voltage follower unit 60, a sampling module 30, and a second compensation module 50.
[0041] The first input terminal of the differential amplifier module 10 is coupled to the first output terminal of the full-bridge circuit 200, and the second input terminal of the differential amplifier module 10 is coupled to the second output terminal of the full-bridge circuit 200. The reference terminal of the differential amplifier module 10 is used to receive the first compensation voltage. The differential amplifier module 10 outputs a first differential voltage based on the first compensation voltage, the first induced voltage, and the second induced voltage.
[0042] For example, the differential amplifier module 10 can be an instrumentation amplifier. The first input terminal of the instrumentation amplifier is coupled to the first output terminal of the full-bridge circuit 200, and the second input terminal of the instrumentation amplifier is coupled to the second output terminal of the full-bridge circuit 200. The reference terminal of the instrumentation amplifier is used to receive the first compensation voltage. The instrumentation amplifier calculates and amplifies the difference between the first induced voltage and the second induced voltage, and outputs the amplified difference along with the first compensation voltage as the first differential voltage.
[0043] The second voltage follower unit 60 is coupled to the second reference voltage terminal and is also coupled to the reference terminal of the instrumentation amplifier. The second reference voltage terminal is used to provide a second voltage, and the second voltage follower unit 60 is used to provide a second compensation voltage to the instrumentation amplifier according to the second voltage.
[0044] The first input terminal of the sampling module 30 is coupled to the output terminal of the instrumentation amplifier, and the second input terminal of the sampling module 30 receives the second compensation voltage. The sampling module 30 is used to output the second differential voltage based on the first differential voltage and the second compensation voltage.
[0045] For example, the sampling module 30 can be a digital-to-analog converter (DAC). The first input terminal of the DAC is coupled to the output terminal of the differential amplifier module 10, and the second input terminal of the DAC is coupled to a first reference voltage terminal. The DAC is used to output a second differential voltage based on the first differential voltage and the second compensation voltage. Figure 4 As shown, in some examples, the first reference voltage terminal can be the reference voltage terminal of the digital-to-analog converter itself.
[0046] like Figure 6 As shown, the second compensation module 50 includes a second digital-to-analog converter 51, which is coupled to the second input terminal of the sampling module 30. The second digital-to-analog converter 51 is used to provide a second compensation voltage.
[0047] The second differential voltage output by the digital-to-analog converter is: V adc_p -V adc_n =(Vp-Vn)*G+V bias *G+V ref -V dac2 Among them, V adc_p Vp is the voltage received at the first input terminal of the digital-to-analog converter, Vn is the first induced voltage, and V is the second induced voltage. ref The first compensation voltage is V, G is the gain of the instrumentation amplifier, and V is the gain of the instrumentation amplifier. bias V is the bias voltage. dac2 This is the second compensation voltage.
[0048] When it is necessary to make the value of the second differential voltage the difference between the first induced voltage and the second induced voltage, the value of the second compensation voltage can be adjusted so that V dac2 = V ref +V bias *G, at this time: V adc_p -V adc_n =(Vp-Vn)*G When the sensor has no external load, i.e., Vp=0, Vn=0, Vadc_p=Vadc_n, the second differential voltage output by the digital-to-analog converter is 0, thus achieving zeroing of the bias voltage. Therefore, the adjustment circuit can compensate for the second differential voltage by adjusting the second compensation voltage to counteract the influence of the bias voltage.
[0049] In some embodiments, the adjustment circuit may further include a filter module 20, which is coupled to the output terminal of the differential amplifier module 10 and is also coupled to the second input terminal of the sampling module 30. The filter module 20 is used to filter the first differential voltage.
[0050] For example, the filtering module 20 may include a low-pass filter unit coupled to the output terminal of the differential amplifier module 10, and the low-pass filter unit is also coupled to the second input terminal of the sampling module 30.
[0051] like Figure 7 As shown, the adjustment circuit includes a differential amplifier module 10, a sampling module 30, a first compensation module 40, and a second compensation module 50.
[0052] The first input terminal of the differential amplifier module 10 is coupled to the first output terminal of the full-bridge circuit 200, and the second input terminal of the differential amplifier module 10 is coupled to the second output terminal of the full-bridge circuit 200. The reference terminal of the differential amplifier module 10 is used to receive the first compensation voltage. The differential amplifier module 10 outputs a first differential voltage based on the first compensation voltage, the first induced voltage, and the second induced voltage.
[0053] For example, the differential amplifier module 10 can be an instrumentation amplifier. The first input terminal of the instrumentation amplifier is coupled to the first output terminal of the full-bridge circuit 200, and the second input terminal of the instrumentation amplifier is coupled to the second output terminal of the full-bridge circuit 200. The reference terminal of the instrumentation amplifier is used to receive the first compensation voltage. The instrumentation amplifier calculates and amplifies the difference between the first induced voltage and the second induced voltage, and outputs the amplified difference along with the first compensation voltage as the first differential voltage.
[0054] The first compensation module 40 includes a first digital-to-analog converter 41 and a first voltage follower unit 42. The first digital-to-analog converter 41 provides a first voltage. The first voltage follower unit 42 is coupled to the first digital-to-analog converter 41 and is also coupled to the reference terminal of the instrumentation amplifier. The first voltage follower unit 42 provides a first compensation voltage to the instrumentation amplifier based on the first voltage. The connection relationship between the first compensation module 40 and the differential amplifier module 10 can be referred to... Figure 3 This will not be elaborated upon here.
[0055] The first input terminal of the sampling module 30 is coupled to the output terminal of the differential amplifier module 10, and the second input terminal of the sampling module 30 receives the second compensation voltage. The sampling module 30 is used to output the second differential voltage based on the first differential voltage and the second compensation voltage.
[0056] For example, the sampling module 30 can be a digital-to-analog converter (DAC). The first input terminal of the DAC is coupled to the output terminal of the differential amplifier module 10, and the second input terminal of the DAC is coupled to a first reference voltage terminal. The DAC is used to output a second differential voltage based on the first differential voltage and the second compensation voltage. Figure 4 As shown, in some examples, the first reference voltage terminal can be the reference voltage terminal of the digital-to-analog converter itself.
[0057] The second compensation module 50 includes a second digital-to-analog converter 51, which is coupled to the second input terminal of the sampling module 30. The second digital-to-analog converter 51 is used to provide a second compensation voltage. The connection relationship between the second compensation module 50 and the sampling module 30 can be found in [reference needed]. Figure 6 This application will not elaborate further.
[0058] The second differential voltage output by the digital-to-analog converter is: V adc_p -V adc_n =(Vp-Vn)*G+V bias *G+V dac1 -V dac2 Among them, V adc_p Vp is the voltage received at the first input terminal of the digital-to-analog converter, Vn is the first induced voltage, and V is the second induced voltage. dac1 The first compensation voltage is V, G is the gain of the instrumentation amplifier, and V is the gain of the instrumentation amplifier. bias V is the bias voltage. dac2 This is the second compensation voltage.
[0059] When it is necessary to make the value of the second differential voltage the difference between the first induced voltage and the second induced voltage, this can be achieved by adjusting the values of the first compensation voltage and the second compensation voltage, so that V dac2 -V dac1 = V bias *G, at this time: V adc_p -V adc_n =(Vp-Vn)*G When the sensor has no external load, i.e., Vp=0, Vn=0, Vadc_p=Vadc_n, the second differential voltage output by the digital-to-analog converter is 0, thus achieving zeroing of the bias voltage. Therefore, the adjustment circuit can compensate for the second differential voltage by adjusting the first compensation voltage and the second compensation voltage to counteract the influence of the bias voltage.
[0060] In some embodiments, the adjustment circuit further includes a filter module 20, which is coupled to the output terminal of the differential amplifier module 10 and also coupled to the second input terminal of the sampling module 30. The filter module 20 is used to filter the first differential voltage.
[0061] For example, the filtering module 20 includes a low-pass filter unit, which is coupled to the output terminal of the differential amplifier module 10 and is also coupled to the second input terminal of the sampling module 30.
[0062] Through the above description of the embodiments, those skilled in the art can clearly understand that the diagnostic methods in the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the related technology, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods of the various embodiments of the present invention.
[0063] Through the above description of the embodiments, those skilled in the art can clearly understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.
[0064] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another apparatus, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.
[0065] The units described as separate components may or may not be physically separate. A component shown as a unit can be one or more physical units; that is, it can be located in one place or distributed in multiple different locations. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.
[0066] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit described above can be implemented in hardware.
[0067] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A full-bridge strain gauge bias voltage adjustment circuit, characterized in that, Applied to a full-bridge circuit, the first output terminal of the full-bridge circuit outputs a first induced voltage, and the second output terminal of the full-bridge circuit outputs a second induced voltage. The adjustment circuit includes: A differential amplifier module, wherein the first input terminal of the differential amplifier module is coupled to the first output terminal of the full-bridge circuit, the second input terminal of the differential amplifier module is coupled to the second output terminal of the full-bridge circuit, the reference terminal of the differential amplifier module is used to receive a first compensation voltage, and the differential amplifier module outputs a first differential voltage based on the first compensation voltage, the first compensation voltage, the first induced voltage, and the second induced voltage; The sampling module has a first input terminal coupled to the output terminal of the differential amplifier module, and a second input terminal receiving a second compensation voltage. The sampling module is used to output a second differential voltage based on the first differential voltage and the second compensation voltage. The adjustment circuit compensates the second differential voltage according to the first compensation voltage and / or the second compensation voltage.
2. The full-bridge strain gauge bias voltage adjustment circuit according to claim 1, characterized in that, The adjustment circuit further includes a first compensation module, which is coupled to the differential amplifier module and is used to provide the first compensation voltage.
3. The full-bridge strain gauge bias voltage adjustment circuit according to claim 2, characterized in that, The first compensation module includes a first digital-to-analog converter unit and a first voltage follower unit. The first digital-to-analog converter unit is used to provide a first voltage. The first voltage follower unit is coupled to the first digital-to-analog converter unit and is also coupled to the reference terminal of the differential amplifier module. The first voltage follower unit is used to provide the first compensation voltage to the differential amplifier module according to the first voltage.
4. The full-bridge strain gauge bias voltage adjustment circuit according to claim 3, characterized in that, The second input terminal of the sampling module is coupled to the first reference voltage terminal, which is used to provide the second compensation voltage. The adjustment circuit adjusts the first compensation voltage by controlling the first digital-to-analog conversion unit to compensate the second differential voltage.
5. The full-bridge strain gauge bias voltage adjustment circuit according to claim 1, characterized in that, The adjustment circuit further includes a second compensation module, which is coupled to the second input terminal of the sampling module and is used to provide the second compensation voltage.
6. The full-bridge strain gauge bias voltage adjustment circuit according to claim 5, characterized in that, The second compensation module includes a second digital-to-analog converter unit, which is coupled to the second input terminal of the sampling module and is used to provide a second compensation voltage.
7. The full-bridge strain gauge bias voltage adjustment circuit according to claim 6, characterized in that, The adjustment circuit further includes a second voltage follower unit, which is coupled to a second reference voltage terminal and also coupled to a reference terminal of the differential amplifier module. The second reference voltage terminal is used to provide a second voltage, and the second voltage follower unit is used to provide a second compensation voltage to the differential amplifier module according to the second voltage. The adjustment circuit adjusts the second compensation voltage by controlling the second digital-to-analog conversion unit to compensate for the second differential voltage.
8. The full-bridge strain gauge bias voltage adjustment circuit according to claim 1, characterized in that, The adjustment circuit includes: The first compensation module includes a first digital-to-analog converter unit and a first voltage follower unit. The first digital-to-analog converter unit is used to provide a first voltage. The first voltage follower unit is coupled to the digital-to-analog converter unit and is also coupled to the differential amplifier module. The first voltage follower unit is used to provide the first compensation voltage to the differential amplifier module according to the first voltage. The second compensation module includes a second digital-to-analog converter unit and a second voltage follower unit. The second digital-to-analog converter unit is used to provide a second voltage. The second voltage follower unit is coupled to the second digital-to-analog converter unit and is also coupled to the second input terminal of the sampling module. The second voltage follower unit is used to provide the second compensation voltage to the sampling module according to the second voltage. The adjustment circuit compensates for the second differential voltage using the first compensation voltage and the second compensation voltage.
9. The full-bridge strain gauge bias voltage adjustment circuit according to any one of claims 1-8, characterized in that, The adjustment circuit further includes a filtering module, which is coupled to the output terminal of the differential amplifier module and also coupled to the second input terminal of the sampling module. The filtering module is used to filter the first differential voltage.
10. The full-bridge strain gauge bias voltage adjustment circuit according to claim 1, characterized in that, The filtering module includes a low-pass filter unit, which is coupled to the output terminal of the differential amplifier module and also coupled to the second input terminal of the sampling module.