A voltage calibration circuit and a method for sampling voltage fitting and voltage calibration

Abstract

The present application provides a voltage calibration circuit, a sampling voltage fitting method, and a voltage calibration method, including: a resistor to be sampled, a first operational amplifier follower circuit, a second operational amplifier follower circuit, and a voltage calibration module; wherein, a first sampling point at one end of the resistor to be sampled is connected to the input end of the first operational amplifier follower circuit; a second sampling point at the other end of the resistor to be sampled is connected to the input end of the second operational amplifier follower circuit; the output end of the first operational amplifier follower circuit outputs a first sampling voltage of the resistor to be sampled, and the output end of the second operational amplifier follower circuit outputs a second sampling voltage of the resistor to be sampled; and the first sampling voltage and the second sampling voltage are input into the voltage calibration module to calibrate the voltage across the resistor to be sampled. The differential circuit is removed, simplifying the original circuit. By removing the differential circuit, the offset error of the operational amplifier chip and the error caused by the resistor itself are avoided, the error caused by the offset of the differential circuit is reduced, and the accuracy of the sampling voltage is improved.

Description

Technical Field

[0001] This application relates to the field of instruments and meters, and particularly to a voltage calibration circuit, a sampling voltage fitting method, and a voltage calibration method. Background Art

[0002] The existing voltage calibration circuit includes both an operational amplifier follower circuit and a differential circuit. Due to the offset voltage of the operational amplifier device itself and the error of the resistor itself, the feedback of the differential circuit is offset, resulting in the existing voltage calibration circuit having defects such as large errors and low sampling accuracy. To solve this problem, a new voltage calibration circuit and a new algorithm for calibrating the sampled voltage value are required. Summary of the Invention

[0003] This application provides a voltage calibration circuit, a sampling voltage fitting method, and a voltage calibration method to solve the problems of large errors and low sampling accuracy in the existing voltage calibration circuit.

[0004] Based on the above problems, in the first aspect of this embodiment, a voltage calibration circuit is provided, including: a resistor to be sampled, a first operational amplifier follower circuit, a second operational amplifier follower circuit, and a voltage calibration module;

[0005] Wherein, a first sampling point at one end of the resistor to be sampled is connected to the input end of the first operational amplifier follower circuit; a second sampling point at the other end of the resistor to be sampled is connected to the input end of the second operational amplifier follower circuit; the output end of the first operational amplifier follower circuit outputs a first sampling voltage of the resistor to be sampled, and the output end of the second operational amplifier follower circuit outputs a second sampling voltage of the resistor to be sampled; and the first sampling voltage and the second sampling voltage are input into the voltage calibration module to calibrate the voltage across the resistor to be sampled.

[0006] In combination with the first aspect, in a possible implementation manner, the voltage calibration module is configured to determine the calibration voltage across the resistor to be sampled according to the correspondence relationship between the calibration voltage across the resistor to be sampled determined in advance and the first sampling voltage and the second sampling voltage, and the received first sampling voltage and the second sampling voltage.

[0007] In combination with the first aspect, in a possible implementation manner, the correspondence relationship is determined by using a preset fitting algorithm, and is a functional relationship with the calibration voltage across the resistor to be sampled as the dependent variable and the first sampling voltage and the second sampling voltage as the independent variables. Wherein, the functional relationship includes a two-dimensional linear relationship; and / or the preset fitting algorithm includes: the least squares method.

[0008] In combination with the first aspect, in a possible implementation manner, the first operational amplifier follower circuit includes: a first operational amplifier;

[0009] The positive input terminal of the first operational amplifier is connected to the first sampling point; the output terminal of the first operational amplifier is connected to the negative input terminal; the feedback terminal of the first operational amplifier is connected to the negative pole of the operational amplifier power supply; the positive and negative power supply terminals of the first operational amplifier are respectively connected to the positive and negative poles of the operational amplifier power supply; the output terminal of the first operational amplifier is connected to the voltage calibration module.

[0010] In combination with the first aspect, in a possible implementation manner, the second operational amplifier follower circuit includes: a second operational amplifier;

[0011] The positive input terminal of the second operational amplifier is connected to the second sampling point; the output terminal of the second operational amplifier is connected to the negative input terminal; the feedback terminal of the second operational amplifier is connected to the negative pole of the operational amplifier power supply; the positive and negative power supply terminals of the second operational amplifier are respectively connected to the positive and negative poles of the operational amplifier power supply; the output terminal of the second operational amplifier is connected to the voltage calibration module.

[0012] In combination with the first aspect, in a possible implementation manner, both ends of the resistor to be sampled are respectively connected to one end of a first current-limiting resistor and a second current-limiting resistor; the other end of the first current-limiting resistor is connected to the first sampling point; the other end of the second current-limiting resistor is connected to the second sampling point; the first sampling point and the second sampling point are respectively grounded through pull-down resistors.

[0013] A second aspect of this embodiment provides a sampling voltage fitting method for a voltage calibration circuit, including:

[0014] Measure the voltage across the resistor to be sampled multiple times, and obtain the true measured voltage value of each measurement, and obtain the first sampling voltage value and the second sampling voltage value corresponding to each measurement;

[0015] Substitute each group of true measured voltage values and the corresponding first sampling voltage value and second sampling voltage value into a pre-established functional relationship with the calibration voltage across the resistor to be sampled as the dependent variable and the first sampling voltage and the second sampling voltage as the independent variables; and solve the coefficients in the functional relationship through a preset fitting algorithm to obtain the functional relationship between the dependent variable and the independent variables after fitting.

[0016] In combination with the second aspect, in a possible implementation manner, the functional relationship includes a two-dimensional linear relationship; and / or the preset fitting algorithm includes: the least squares method.

[0017] A third aspect of this embodiment provides a voltage calibration method for a voltage calibration circuit, including:

[0018] Obtain the first sampling voltage and the second sampling voltage;

[0019] Based on the pre-determined correspondence between the calibration voltage across the resistor to be sampled and the first sampling voltage and the second sampling voltage, the calibration voltage across the resistor to be sampled is determined based on the acquired first sampling voltage and the second sampling voltage.

[0020] The fourth aspect of this embodiment provides an electronic device, including: the voltage calibration circuit described in the first aspect.

[0021] The beneficial effects of the embodiments of this application include:

[0022] This embodiment provides a voltage calibration circuit, including: a resistor to be sampled, a first operational amplifier follower circuit, a second operational amplifier follower circuit, and a voltage calibration module; wherein, a first sampling point at one end of the resistor to be sampled is connected to the input end of the first operational amplifier follower circuit; a second sampling point at the other end of the resistor to be sampled is connected to the input end of the second operational amplifier follower circuit; the output end of the first operational amplifier follower circuit outputs the first sampling voltage of the resistor to be sampled, and the output end of the second operational amplifier follower circuit outputs the second sampling voltage of the resistor to be sampled; and the first sampling voltage and the second sampling voltage are input into the voltage calibration module to calibrate the voltage across the resistor to be sampled. The voltage calibration circuit provided by the embodiments of this application includes a first operational amplifier follower circuit and a second operational amplifier follower circuit. Compared with the prior art, the differential circuit is removed, which not only simplifies the original circuit, but also avoids the offset error of the operational amplifier chip and the error caused by the resistor itself by removing the differential circuit, thereby reducing the error caused by the offset of the differential circuit and improving the accuracy of the sampling voltage.

[0023] This embodiment provides a sampling voltage fitting method for a voltage calibration circuit and a voltage calibration method for a voltage calibration circuit. The sampled voltage value calibrated by the method is closer to the measured voltage value. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings here are incorporated into the description and constitute a part of this specification, showing embodiments consistent with this application, and are used together with the specification to explain the principles of this application.

[0025] Figure 1 It is a connection schematic diagram of the voltage calibration circuit provided in the related art;

[0026] Figure 2 It is a connection schematic diagram of the voltage calibration circuit provided by the embodiments of this application;

[0027] Figure 3 It is a flow chart of the sampling voltage fitting method provided by the embodiments of this application;

[0028] Figure 4 It is a flow chart of the voltage calibration method of the voltage calibration circuit provided by the embodiments of this application.

[0029] Reference numerals:

[0030] Sampling resistor 1, first operational amplifier follower circuit 2, second operational amplifier follower circuit 3, voltage calibration module 4, first sampling point 5, second sampling point 6, differential operational amplifier circuit 7. Detailed implementation manners

[0031] The embodiments of the present application provide a voltage calibration circuit and a method for sampling voltage fitting and voltage calibration. The preferred embodiments of the present application will be described below with reference to the accompanying drawings of the specification. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application. And without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0032] In practical applications, it is often necessary to obtain the voltage across a certain device in a circuit for subsequent calculations. In the related art, a voltage calibration circuit is set in the circuit to obtain the voltage across the device. The existing voltage calibration circuit first measures the voltage drop at the measured location through two operational amplifier follower circuits and a second-order differential circuit, and then calibrates the measured voltage drop through the voltage calibration module to obtain the true voltage at the measured location. Figure 1 The connection schematic diagram of a voltage calibration circuit provided in the related art is shown. The voltage calibration circuit includes: a sampling resistor 1 to be measured, a first operational amplifier follower circuit 2, a second operational amplifier follower circuit 3, a differential operational amplifier circuit 7, and a voltage calibration module 4. The first operational amplifier follower circuit 2, the second operational amplifier follower circuit 3, and the differential operational amplifier circuit 7 all include: an operational amplifier; the operational amplifier includes a positive input terminal, a negative input terminal, a positive power supply terminal of the operational amplifier, a negative power supply terminal of the operational amplifier, an output terminal, and a feedback terminal.

[0033] Continue to refer to Figure 1 , the first sampling point 5 at one end of the sampling resistor 1 to be measured is connected to the input terminal of the first operational amplifier follower circuit 2; the second sampling point 6 at the other end of the sampling resistor 1 to be measured is connected to the input terminal of the second operational amplifier follower circuit 3; the output terminal of the first operational amplifier follower circuit 2 outputs the first sampling voltage of the sampling resistor 1 to be measured, and the output terminal of the second operational amplifier follower circuit 3 outputs the second sampling voltage of the sampling resistor 1 to be measured; and the first sampling voltage is input to the positive input terminal of the differential operational amplifier circuit 7; the second sampling voltage is input to the negative input terminal of the differential operational amplifier circuit 7; the output terminal of the differential operational amplifier circuit 7 is connected to the voltage calibration module.

[0034] The two ends of the resistor 1 to be sampled are connected to two sampling points through current limiting resistors, and the two sampling points are grounded through pull-down resistors; the output end of the first operational amplifier follower circuit 2 is connected to the positive input end of the differential operational amplifier circuit 7 through a current limiting resistor; the output end of the second operational amplifier follower circuit 3 is connected to the reverse input end of the differential operational amplifier circuit 7 through a current limiting resistor; the positive input end of the differential operational amplifier circuit 7 is grounded through another resistor; the reverse input end of the differential operational amplifier circuit 7 is connected to the output end of the differential operational amplifier circuit 7 through another resistor.

[0035] Figure 1 The resistor design values shown in , which is only for illustration and not for limitation.

[0036] According to the voltage calibration method of the voltage calibration module in the related art, the output sampling voltage Calibrate; where is the sampled voltage value output by the differential operational amplifier circuit 7; is the first sampling voltage, is the second sampling voltage.

[0037] Then use one-dimensional linear fitting The calibration voltage value that represents the actual voltage value of the resistor to be sampled measured by the voltmeter And the sampling voltage value Two numerical relationships, where the coefficient , The value of is known, and the measured sample voltage value Substitution , then the calibrated sampling value can be obtained , that is, the sampled value after calibration is considered to be the actual voltage value.

[0038] However, the above voltage calibration method is analyzed under ideal conditions. In the actual measurement process, the op amp has an offset voltage, and the resistance value deviates from the designed resistance value due to the influence of the environment and manufacturing process, resulting in differential feedback offset. This is not true. At this time, the voltage sampling formula should be: .

[0039] The following example illustrates that the design resistance value is set to of The actual resistance values are , take 6 data points for calibration, use one-dimensional fitting method to get the function relationship, and the sample value after calibration The deviations and standard deviations relative to the set values are shown in Table 1;

[0040]

[0041] Table 1

[0042] It can be seen that the calibration voltage obtained by using the voltage calibration method provided in the related technology has a large error.

[0043] An embodiment of the present application provides a voltage calibration circuit, as Figure 2 shown, including: a to-be-sampled resistor 1, a first operational amplifier follower circuit 2, a second operational amplifier follower circuit 3, and a voltage calibration module 4;

[0044] Among them, a first sampling point 5 at one end of the to-be-sampled resistor 1 is connected to the input end of the first operational amplifier follower circuit 2; a second sampling point 6 at the other end of the to-be-sampled resistor 1 is connected to the input end of the second operational amplifier follower circuit 3; the output end of the first operational amplifier follower circuit 2 outputs a first sampling voltage of the to-be-sampled resistor 1, and the output end of the second operational amplifier follower circuit 3 outputs a second sampling voltage of the to-be-sampled resistor 1; and the first sampling voltage and the second sampling voltage are input into the voltage calibration module 4 to calibrate the voltage across the to-be-sampled resistor 1.

[0045] In the embodiment of the present application, the first sampling voltage and the second sampling voltage output by the first operational amplifier follower circuit 2 and the second operational amplifier follower circuit 3 are directly input into the voltage calibration module without being processed by a differential circuit. The voltage calibration circuit provided by the embodiment of the present application removes the differential circuit, which not only simplifies the original circuit, but also avoids the offset error of the operational amplifier chip and the error caused by the resistor itself by removing the differential circuit, thereby reducing the error caused by the offset of the differential circuit.

[0046] In another embodiment provided by the present application, the voltage calibration module 4 is configured to determine the calibration voltage across the to-be-sampled resistor 1 according to the correspondence relationship between the calibration voltage across the to-be-sampled resistor 1 determined in advance and the first sampling voltage and the second sampling voltage, and the received first sampling voltage and the second sampling voltage.

[0047] In the embodiment of the present application, the correspondence relationship between the calibration voltage across the to-be-sampled resistor 1 and the first sampling voltage and the second sampling voltage can be determined in advance. For example, multiple groups of true voltages across the to-be-sampled resistor 1, as well as the first sampling voltage and the second sampling voltage, can be measured in advance, and their correspondence relationship is recorded. During the operation of the circuit, the true voltage value across the corresponding to-be-sampled resistor 1 is queried according to the values of the first sampling voltage and the second sampling voltage obtained by sampling, and the queried true voltage value is used as the calibrated voltage value.

[0048] In another embodiment provided by the present application, the above correspondence relationship is a functional relationship determined by using a preset fitting algorithm, with the calibration voltage across the to-be-sampled resistor 1 as the dependent variable and the first sampling voltage and the second sampling voltage as the independent variables.

[0049] In the embodiments of the present application, since the voltage calibration algorithm provided by the related art is no longer applicable, according to the calibration circuit provided by the embodiments of the present application, in the application, the calibration voltage across the resistor 1 to be sampled is determined by the first sampled voltage and the second sampled voltage obtained by sampling. Then, in the embodiments of the present application, the first sampled voltage and the second sampled voltage can be used as independent variables, and the calibration voltage can be used as the dependent variable. Through a preset fitting algorithm, the functional relationship between the calibration voltage and the first sampled voltage and the second sampled voltage is determined. Since the true voltage across the resistor 1 to be sampled can be measured, and the first sampled voltage and the second sampled voltage can also be measured, multiple sets of true voltages, the first sampled voltage, and the second sampled voltage can be measured, and the preset fitting algorithm can be used to fit the true voltage with the first sampled voltage and the second sampled voltage based on multiple sets of data to obtain the functional relationship between the true voltage and the first sampled voltage and the second sampled voltage. Then, in subsequent applications, after measuring the first sampled voltage and the second sampled voltage, the first sampled voltage and the second sampled voltage can be calibrated through this functional relationship, that is, the calibration voltage approximate to the true voltage is obtained.

[0050] In another embodiment provided by the present application, as Figure 2 shown, the first operational amplifier follower circuit 2 includes: a first operational amplifier; the second operational amplifier follower circuit 3 includes: a second operational amplifier; an operational amplifier is a device that has the function of adjusting and amplifying analog signals, including: a positive input terminal, a negative input terminal, a positive power supply terminal of the operational amplifier, a negative power supply terminal of the operational amplifier, an output terminal, and a feedback terminal.

[0051] The positive input terminal of the first operational amplifier 2 is connected to the first sampling point 5; the output terminal of the first operational amplifier 2 is connected to the negative input terminal; the feedback terminal of the first operational amplifier 2 is connected to the negative power supply terminal of the operational amplifier; the positive and negative power supply terminals of the first operational amplifier 2 are respectively connected to the positive and negative power supply terminals of the operational amplifier; the output terminal of the first operational amplifier 2 is connected to the voltage calibration module 4.

[0052] The positive input terminal of the second operational amplifier 3 is connected to the second sampling point 6; the output terminal of the second operational amplifier 3 is connected to the negative input terminal; the feedback terminal of the second operational amplifier 3 is connected to the negative power supply terminal of the operational amplifier; the positive and negative power supply terminals of the second operational amplifier 3 are respectively connected to the positive and negative power supply terminals of the operational amplifier; the output terminal of the second operational amplifier 3 is connected to the voltage calibration module 4.

[0053] In another embodiment provided by the present application, as Figure 2 shown, both ends of the resistor 1 to be sampled are respectively connected to one end of a first current-limiting resistor and a second current-limiting resistor; the other end of the first current-limiting resistor is connected to the first sampling point 5; the other end of the second current-limiting resistor is connected to the second sampling point 6; the first sampling point 5 and the second sampling point 6 are respectively grounded through pull-down resistors.

[0054] In the embodiments of the present application, Figure 2 the designed resistance values shown in may all be

[0055] merely for illustration and not for limitation. Figure 3 The embodiments of the present application provide a sampling voltage fitting method based on the circuit. As

[0056] shown, the process of the sampling voltage fitting method includes:

[0057] S301. Measure the voltage across the to-be-sampled resistor multiple times, obtain the true measured voltage value for each measurement, and obtain the first sampling voltage value and the second sampling voltage value corresponding to each measurement;

[0058] S302. Substitute each group of true measured voltage values, as well as the corresponding first sampling voltage value and second sampling voltage value, into a pre-established functional relationship with the calibration voltage across the to-be-sampled resistor as the dependent variable and the first sampling voltage and the second sampling voltage as the independent variables;

[0059] S303. Solve for the coefficients in the functional relationship through a preset fitting algorithm to obtain the functional relationship between the fitted dependent variable and the independent variables.

[0059] In the embodiments of the present application, the true voltage value across the to-be-sampled resistor can be measured multiple times, as well as the first sampling voltage value and the second sampling voltage value corresponding to each measurement, to form multiple data groups consisting of the corresponding true voltage value, the corresponding first sampling voltage value, and the second sampling voltage value.

[0060] In a possible implementation manner, the pre-established sampling voltage fitting functional relationship can be a two-dimensional fitting, that is where is the first sampling voltage value, is the second sampling voltage value, is the true voltage value, and the preset fitting algorithm adopted can be the least squares method. Then, multiple groups of true voltage values, the first sampling voltage, and the second sampling voltage can be respectively substituted into this functional relationship, and the least squares method can be applied for calculation to obtain the values of the coefficients to obtain a functional relationship with the calibration voltage across the to-be-sampled resistor as the dependent variable and the first sampling voltage and the second sampling voltage as the independent variables: where is the acquired value after two-dimensional fitting calibration.

[0061] In another embodiment provided by the embodiments of the present application, the functional relationship includes a two-dimensional linear relationship; and / or the preset fitting algorithm includes: the least squares method.

[0062] The embodiments of the present application further provide a voltage calibration method based on the voltage calibration circuit. As Figure 4As shown in the figure, it includes:

[0063] S401. Obtain the first sampling voltage and the second sampling voltage ;

[0064] S402. Based on the functional relationship formed between the calibration voltage across the resistor to be sampled and the first sampling voltage and the second sampling voltage determined in advance , determine the calibration voltage across the resistor to be sampled based on the obtained first sampling voltage and the second sampling voltage.

[0065] Table 2 shows the errors and standard deviations of the calibrated sampling values relative to the set values obtained by applying this embodiment. Compared with Table 1, the errors and standard deviations of the sampling values obtained by applying this embodiment are significantly lower, indicating that the calibration accuracy of this application is significantly improved compared with the prior art, and the problems existing in the prior art are solved.

[0066]

[0067] Table 2

[0068] In summary, the voltage calibration circuit applied in this embodiment has a simple structure, avoids the offset errors of the operational amplifier chip and resistor devices, thereby avoiding the errors caused by the offset of the differential circuit, and improves the sampling accuracy.

[0069] The embodiment of the present application provides an electronic device, including the voltage calibration circuit described in any of the above embodiments.

[0070] The sampling voltage fitting method and voltage calibration method applied in this embodiment adopt a two-dimensional fitting method, improve the linearity of the functional relationship, and reduce the error between the collected value after calibration and the actual voltage value.

[0071] Those skilled in the art can understand that the drawings are only schematic diagrams of a preferred embodiment, and the modules or processes in the drawings are not necessarily essential for implementing the present application.

[0072] Those skilled in the art can understand that the modules in the device in the embodiment can be distributed in the device in the embodiment according to the description in the embodiment, or can be correspondingly changed to be located in one or more devices different from this embodiment. The modules in the above embodiments can be combined into one module, or further split into multiple sub-modules.

[0073] The serial numbers of the embodiments of the present application above are only for description and do not represent the advantages or disadvantages of the embodiments.

[0074] Obviously, those skilled in the art can make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalent technologies, this application is also intended to include these modifications and variations.

Claims

1. A voltage calibration circuit, characterized in that, Including: A resistor to be sampled, a first operational amplifier follower circuit, a second operational amplifier follower circuit, and a voltage calibration module; Wherein, a first sampling point at one end of the resistor to be sampled is connected to the input end of the first operational amplifier follower circuit; a second sampling point at the other end of the resistor to be sampled is connected to the input end of the second operational amplifier follower circuit; the output end of the first operational amplifier follower circuit outputs a first sampling voltage of the resistor to be sampled, and the output end of the second operational amplifier follower circuit outputs a second sampling voltage of the resistor to be sampled; the first sampling voltage and the second sampling voltage are directly input into the voltage calibration module without passing through a differential operational amplifier circuit to calibrate the voltage across the resistor to be sampled; The voltage calibration module is configured to determine the calibration voltage across the resistor to be sampled according to a pre-determined correspondence relationship between the calibration voltage across the resistor to be sampled and the first sampling voltage and the second sampling voltage, and the received first sampling voltage and second sampling voltage; the correspondence relationship is determined by using a preset fitting algorithm, which is a functional relationship with the calibration voltage across the resistor to be sampled as the dependent variable and the first sampling voltage and the second sampling voltage as the independent variables; wherein, the functional relationship is a two-dimensional linear relationship.

2. The circuit according to claim 1, wherein The preset fitting algorithm is the least squares method.

3. The circuit according to claim 1, wherein The first operational amplifier follower circuit includes: a first operational amplifier; The non-inverting input end of the first operational amplifier is connected to the first sampling point; the output end of the first operational amplifier is connected to the inverting input end; the feedback end of the first operational amplifier is connected to the negative pole of the operational amplifier power supply; the positive and negative power supply terminals of the first operational amplifier are respectively connected to the positive and negative poles of the operational amplifier power supply; the output end of the first operational amplifier is connected to the voltage calibration module.

4. The circuit according to claim 1, wherein The second operational amplifier follower circuit includes: a second operational amplifier; The non-inverting input end of the second operational amplifier is connected to the second sampling point; the output end of the second operational amplifier is connected to the inverting input end; the feedback end of the second operational amplifier is connected to the negative pole of the operational amplifier power supply; the positive and negative power supply terminals of the second operational amplifier are respectively connected to the positive and negative poles of the operational amplifier power supply; the output end of the second operational amplifier is connected to the voltage calibration module.

5. The circuit according to claim 1, characterized in that, Both ends of the resistor to be sampled are respectively connected to one end of a first current-limiting resistor and a second current-limiting resistor; the other end of the first current-limiting resistor is connected to the first sampling point; the other end of the second current-limiting resistor is connected to the second sampling point; the first sampling point and the second sampling point are respectively grounded through pull-down resistors.

6. A sampling voltage fitting method based on the voltage calibration circuit according to any one of claims 1-5, characterized in that, Including: Measure the voltage across the resistor to be sampled multiple times, and obtain the true measured voltage value of each measurement, and obtain the first sampling voltage value and the second sampling voltage value corresponding to each measurement; Substitute each group of true measured voltage values and the corresponding first sampling voltage value and second sampling voltage value into a pre-established functional relationship with the calibration voltage across the resistor to be sampled as the dependent variable and the first sampling voltage and the second sampling voltage as the independent variables; and Solve the coefficients in the functional relationship by a preset fitting algorithm to obtain the functional relationship between the dependent variable and the independent variable after fitting.

7. The method according to claim 6, characterized in that The functional relationship includes a two-dimensional linear relationship; and / or the preset fitting algorithm includes: the least squares method.

8. A voltage calibration method based on the voltage calibration circuit according to any one of claims 1-5, characterized in that, Includes: Obtain the first sampling voltage and the second sampling voltage; Based on the obtained first sampling voltage and the second sampling voltage, determine the calibration voltage across the resistor to be sampled according to the correspondence between the calibration voltage across the resistor to be sampled determined in advance and the first sampling voltage and the second sampling voltage.

9. An electronic device, characterized in that, Includes: The voltage calibration circuit according to any one of claims 1-5.

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