Digital potentiometer calibration circuit and system

Abstract

The utility model discloses a digital potentiometer calibration circuit and system. The circuit comprises at least one partial pressure calibration branch, a calibration branch and a control module, the voltage division calibration branch comprises at least two voltage division resistors; the control module is electrically connected with the partial pressure output end of the partial pressure calibration branch and is used for determining calibration parameters according to the output voltage of the partial pressure calibration branch and the resistance value of the partial pressure resistor; the calibration branch comprises an auxiliary calibration resistor and a connection port electrically connected with the auxiliary calibration resistor, and the connection port is used for accessing a digital potentiometer; the output end of the calibration branch is electrically connected with the control module; and the control module is also used for determining the calibration resistance of the digital potentiometer according to the output voltage of the calibration branch, the calibration parameter and the resistance value of the auxiliary calibration resistor. According to the technical scheme of the embodiment of the utility model, the time and labor cost of manual calibration are reduced, the calibration efficiency is improved, errors caused by manual operation are reduced, and the calibration precision is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of potentiometer, especially to a digital potentiometer calibration circuit and system. BACKGROUND

[0002] Digital potentiometers are widely used in electronic systems to adjust voltage, current and other parameters. However, due to the limitations of manufacturing processes and technologies, there is a certain resistance drift in digital potentiometers on the market, especially the maximum resistance value and the resistance range of the vernier resistance will change. In systems with high precision requirements, uncalibrated digital potentiometers may introduce large system errors, affecting the measurement and control accuracy.

[0003] The existing calibration method is mainly manual calibration, which relies on high-precision multimeters for measurement, and then manually inputs the measurement results into the system. However, manual calibration is time-consuming and labor-intensive, and is prone to measurement errors, affecting the accuracy of the final calibration results. UTILITY MODEL CONTENT

[0004] The utility model provides a kind of digital potentiometer calibration circuit and system, to accurately calibrate digital potentiometer, improve calibration efficiency.

[0005] According to an aspect of the utility model, a digital potentiometer calibration circuit is provided, comprising at least one voltage division calibration circuit branch, a potentiometer calibration circuit branch and a control module digital potentiometer;

[0006] The voltage division calibration circuit branch includes at least two voltage division resistors;

[0007] The control module is electrically connected to the voltage division output end of the voltage division calibration branch, and is used to determine the calibration parameter according to the output voltage of the voltage division calibration branch and the resistance value of the voltage division resistor;

[0008] The calibration branch includes an auxiliary calibration resistor and a connection port electrically connected to the auxiliary calibration resistor, and the connection port is used to access the digital potentiometer;The output end of the calibration branch is electrically connected to the control module;

[0009] The control module is also used to determine the calibration resistance of the digital potentiometer according to the output voltage of the calibration branch, the calibration parameter and the resistance value of the auxiliary calibration resistor.

[0010] Optionally, the connection port and the auxiliary calibration resistor are connected in series, and the common end connected to the connection port and the auxiliary calibration resistor serves as the output end of the calibration branch.

[0011] Optionally, the calibration branch is connected in parallel with the voltage division calibration branch.

[0012] Optionally, the digital potentiometer calibration circuit comprises a first voltage division calibration branch and a second voltage division calibration branch.

[0013] The control module is electrically connected with a first voltage division output end of the first voltage division calibration branch and a second voltage division output end of the second voltage division calibration branch respectively, and is configured to determine first and second calibration parameters according to a first output voltage of the first voltage division output end, a second output voltage of the second voltage division output end, a resistance value of a voltage division resistor in the first voltage division calibration branch, and a resistance value of a voltage division resistor in the second voltage division calibration branch.

[0014] The control module is configured to calibrate the resistance of the digital potentiometer according to a set rule, wherein the set rule is:

[0015] Rx=kx+b-R0; wherein k is the first calibration parameter, b is the second calibration parameter, Rx is the resistance value of the digital potentiometer, x is the output voltage of the calibration branch, and R0 is the resistance value of the auxiliary calibration resistor.

[0016] Optionally, the digital potentiometer calibration circuit comprises a first voltage division calibration branch and a second voltage division calibration branch; the control module is electrically connected with a first voltage division output end of the first voltage division calibration branch and a second voltage division output end of the second voltage division calibration branch respectively, and is configured to determine first and second calibration parameters according to a first output voltage of the first voltage division output end, a second output voltage of the second voltage division output end, a resistance value of a voltage division resistor in the first voltage division calibration branch, a resistance value of a voltage division resistor in the second voltage division calibration branch, and first and second reference voltages inputted by the first and second voltage division calibration branches.

[0017] The control module is configured to calibrate the output voltage of the calibration branch to obtain a calibrated voltage according to the first calibration parameter and the second calibration parameter, and calibrate the resistance of the digital potentiometer according to the calibrated voltage, the first reference voltage, the second reference voltage, and the resistance value of the auxiliary calibration resistor.

[0018] Optionally, the first voltage division calibration branch comprises a first voltage division resistor and a second voltage division resistor connected in series.

[0019] The second voltage division calibration branch comprises a third voltage division resistor and a fourth voltage division resistor connected in series.

[0020] The first voltage division calibration branch is connected in parallel with the second voltage division calibration branch, and a voltage division ratio of the first voltage division calibration branch and the second voltage division calibration branch is not equal. Optionally, the voltage division calibration branch further comprises a first switch connected in series with a voltage division resistor in the voltage division calibration branch; the first switch is electrically connected with the control module, and the control module is configured to control conduction of the first switch in a calibration coefficient determination stage.

[0021] Optionally, the calibration branch further comprises a second switch connected in series between the auxiliary calibration resistor and the connection port; the second switch is electrically connected with the control module, and the control module is configured to control conduction of the second switch in a digital potentiometer calibration stage.

[0022] According to another aspect of the present application, a digital potentiometer calibration system is provided, which comprises the digital potentiometer calibration circuit according to any one of the embodiments of the present application.

[0023] Optionally, the digital potentiometer calibration system further comprises a third switch and a fourth switch; the third switch is connected in series between the auxiliary calibration resistor and the connection port; a first end of the fourth switch is electrically connected with the connection port, and a second end of the fourth switch is electrically connected with a functional circuit;

[0024] The third switch and the fourth switch are respectively electrically connected with the control module, and the control module is further configured to control conduction of the third switch in a digital potentiometer calibration stage and control conduction of the fourth switch in a normal working stage.

[0025] The technical scheme of the present application comprises at least one voltage division calibration branch, a calibration branch and a control module; the control module is electrically connected with a voltage division output end of the voltage division calibration branch, and the control module can determine a calibration parameter according to an output voltage of the voltage division calibration branch and a resistance value of a voltage division resistor in the voltage division calibration branch, and determine a calibration resistor of a digital potentiometer according to an output voltage of the calibration branch, the calibration parameter and a resistance value of an auxiliary calibration resistor in the calibration branch. The technical scheme of the present application determines the calibration parameter through the voltage division calibration branch, and the control module can correct an error of the calibration resistor of the digital potentiometer caused by a voltage error obtained by the analog-to-digital converter according to the calibration parameter, thereby improving the accuracy of the calibration, reducing the time and labor cost of manual calibration, improving the calibration efficiency, reducing the error caused by manual operation and improving the calibration precision.

[0026] It should be understood that the content described in this part is not intended to identify key or important features of the embodiments of the present application, nor is it used to limit the scope of the present application. Other features of the present application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to make the technical scheme in the embodiments of the present application clearer, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of these drawings.

[0028] Figure 1 is a structural schematic diagram of a digital potentiometer calibration circuit according to the embodiment of the present application;

[0029] Figure 2 is a schematic diagram of a digital potentiometer calibration circuit according to the embodiment of the present application;

[0030] Figure 3 is another schematic diagram of a digital potentiometer calibration circuit according to the embodiment of the present application;

[0031] Figure 4 is a structural schematic diagram of a digital potentiometer calibration system according to the embodiment of the present application. DETAILED DESCRIPTION

[0032] In order to make the technical scheme in the embodiments of the present application clearer, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of these drawings.

[0033] It should be noted that the terms "first", "second", and the like in the description and claims of the present application and the above drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not necessarily limit to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0034] Figure 1It is a kind of digital potentiometer calibration circuit's structure schematic diagram according to the embodiment of the utility model, this embodiment can be applicable to digital potentiometer calibration condition, this circuit can be used in electronic product manufacturing, industrial control system and integrated circuit. Figure 1 As shown in the figure, the circuit comprises: at least one voltage division calibration branch 101, a calibration branch 102 and a control module 103.

[0035] The voltage division calibration branch 101 comprises at least two voltage division resistors; the control module 103 is electrically connected with the voltage division output end of the voltage division calibration branch 101, for determining calibration parameters according to the output voltage of the voltage division calibration branch 101 and the resistance value of the voltage division resistor; the calibration branch 102 comprises an auxiliary calibration resistor R5 and a connection port 1021 electrically connected with the auxiliary calibration resistor R5, and the connection port 1021 is used for accessing the digital potentiometer; the output end of the calibration branch 102 is electrically connected with the control module 103; the control module 103 is further used for determining the calibration resistor of the digital potentiometer according to the output voltage of the calibration branch 102, the calibration parameters and the resistance value of the auxiliary calibration resistor R5.

[0036] Among them, at least two voltage division resistors in voltage division calibration branch 101 are connected in series. The control module 103 can obtain the output voltage of the voltage division calibration branch 101, for example, the control module 103 is integrated with an analog-to-digital converter, and the control module 103 can obtain the output voltage of the voltage division calibration branch 101 through the analog-to-digital converter. The voltage division resistor can be a fixed resistor with a known resistance value.

[0037] The calibration parameter refers to a parameter that needs to be adjusted or compensated in circuit design and application to ensure the performance and accuracy of the circuit. In this embodiment, the calibration parameter can be used to calibrate the error of the digital potentiometer caused by the voltage error obtained by the analog-to-digital converter. In some optional embodiments of the present application, the control module 103 can calibrate the voltage obtained by the analog-to-digital converter according to the calibration parameter, thereby ensuring the accuracy of the calibration resistance of the digital potentiometer. In other optional embodiments, the control module 103 can use the calibration parameter as a coefficient for determining the calibration resistance of the digital potentiometer according to the output voltage of the calibration branch 102. Specifically, the number of calibration parameters can be at least one, and in some optional embodiments, the number of calibration parameters is two, which is determined by the control module 103 according to the output voltage obtained by the at least one voltage division calibration branch and the resistance value of the voltage division resistance. Specifically, in the case where the calibration parameter is used to calibrate the voltage obtained by the analog-to-digital converter, the calibration parameter can be determined according to the output voltage of the voltage division calibration branch 101, the resistance value of the voltage division resistance, the theoretical voltage output by the voltage division output voltage 101, and the actual output voltage of the voltage division calibration branch 101. Then, according to the actual output voltage and the corresponding theoretical voltage obtained by the voltage division calibration branch 101, the calibration parameter is determined. In the case where the calibration parameter is directly used as a coefficient for determining the calibration resistance of the digital potentiometer according to the output voltage of the calibration branch, the coefficient in the relationship between the output voltage and the total resistance of the voltage division calibration branch can be determined as the calibration parameter according to the output voltage of the voltage division calibration branch and the total resistance of the voltage division calibration branch.

[0038] The calibration branch 102 is electrically connected to the auxiliary calibration resistance R5 and the connection port 1021 for connecting the digital potentiometer. Optionally, the auxiliary calibration resistance R5 is connected in series or parallel with the connection port 1021 for connecting the digital potentiometer. Figure 1 The auxiliary calibration resistance R5 is connected in series between the power supply and the ground. The auxiliary calibration resistance R5 can be a high-precision fixed resistance with a known resistance value, such as a 0.05% high-precision 1kΩ resistance

[0039] The output voltage of the calibration branch 102 can be obtained by the analog-to-digital converter, and the control module 103 determines the calibration resistance of the digital potentiometer according to the output voltage of the calibration branch, the calibration parameter, and the resistance value of the auxiliary calibration resistance R5. In the case where the control module 103 can calibrate the voltage obtained by the analog-to-digital converter according to the calibration parameter, the calibration voltage after the calibration of the output voltage of the calibration branch 102 obtained by the analog-to-digital converter according to the calibration parameter, the total voltage of the calibration branch 102, and the resistance value of the auxiliary calibration resistance R5 can be used to determine the calibration resistance of the digital potentiometer based on the current relationship. For example, the calibration resistance of the digital potentiometer can be determined according to the calibration voltage, the total voltage of the calibration branch 102, and the resistance value of the auxiliary calibration resistance R5. Figure 1In the shown case, the ratio of the calibration voltage to the calibration resistance of the digital potentiometer is equal to the ratio of the supply voltage to the total resistance, which is equal to the sum of the auxiliary calibration resistance R5 and the calibration resistance of the digital potentiometer, in the above equation, only the calibration resistance of the digital potentiometer is unknown, and the calibration resistance of the digital potentiometer can be obtained accordingly. In the case where the control module 103 can determine the calibration parameter as a coefficient of the calibration resistance of the digital potentiometer according to the output voltage of the calibration branch 102, the calibration resistance of the digital potentiometer is obtained according to the output voltage of the calibration branch 102, the resistance value of the auxiliary calibration resistance R5 and the calibration parameter.

[0040] The control module 103 is also connected to the digital potentiometer, and the control module 103 determines the calibration resistance of the digital potentiometer according to the output voltage of the calibration branch 102, the calibration parameter and the resistance value of the auxiliary calibration resistance R5, and transmits the calibration resistance to the digital potentiometer through a communication protocol, so as to drive the digital potentiometer to calibrate. The communication protocol can be a serial peripheral interface (SPI), and the SPI protocol has the characteristics of simplicity, high speed and reliability, and is widely used in industrial automation, communication, aerospace and other fields.

[0041] The technical scheme of the embodiment of the utility model discloses at least one voltage division calibration branch, calibration branch and control module, the control module is electrically connected with the voltage division output end of voltage division calibration branch, and the control module can determine the calibration parameter according to the output voltage of voltage division calibration branch and the resistance value of the voltage division resistance in voltage division calibration branch, and determine the calibration resistance of digital potentiometer according to the output voltage of calibration branch, calibration parameter and the resistance value of auxiliary calibration resistance in calibration branch. The technical scheme of the embodiment of the utility model discloses that the calibration parameter is determined through voltage division calibration branch, and the control module can correct the error of the voltage error obtained by the analog-digital converter according to the calibration parameter, so as to improve the accuracy of calibration, reduce the time and labor cost of manual calibration, improve the calibration efficiency, reduce the error caused by manual operation, and improve the calibration precision.

[0042] In some optional embodiments of the utility model, the connection port 1021 is connected in series with the auxiliary calibration resistance R5, and the common end connected by the connection port 1021 and the auxiliary calibration resistance R5 serves as the output end of the calibration branch.

[0043] The connection port 1021 is connected in series with the auxiliary calibration resistance R5, and the common end connected by the connection port 1021 and the auxiliary calibration resistance R5 can be connected to the analog-digital converter of the control module 103, the analog-digital converter is used for collecting the output voltage of the calibration branch, and the control module 103 determines the resistance value of the digital potentiometer according to the output voltage of the calibration branch 102, the calibration parameter and the resistance value of the auxiliary calibration resistance R5.

[0044] Figure 2 It is a kind of digital potentiometer calibration circuit schematic diagram according to the embodiment of the utility model. Reference Figure 2 In some optional embodiments of the utility model, the calibration branch 202 is connected in parallel with the voltage division calibration branch 201.

[0045] Among them, by connecting the calibration branch 202 and the voltage division calibration branch 201 in parallel, the accuracy of the measurement result can be ensured. The calibration parameter is obtained by the voltage division calibration branch 201, to ensure the accuracy of the data collected during the digital potentiometer calibration.

[0046] Continue to refer to Figure 2 In some optional embodiments of the utility model, the voltage division calibration branch 201 includes a first voltage division calibration branch 2011 and a second voltage division calibration branch 2012.

[0047] The control module is electrically connected with the first voltage division output end ADC1 of the first voltage division calibration branch 2011 and the second voltage division output end ADC2 of the second voltage division calibration branch 2012 respectively, for determining the first calibration parameter and the second calibration parameter according to the first output voltage of the first voltage division output end ADC1 and the second output voltage of the second voltage division output end ADC2, the resistance value of the voltage division resistor in the first voltage division calibration branch 2011 and the resistance value of the voltage division resistor in the second voltage division calibration branch 2012.

[0048] The control module is used for calibrating the resistance of the digital potentiometer according to the set rule, wherein the set rule is:

[0049] Rx=kx+b-R0; wherein k is a first calibration parameter, b is a second calibration parameter, Rx is the resistance value of the digital potentiometer, x is the output voltage of the calibration branch, and R0 is the resistance value of the auxiliary calibration resistor. The voltage dividing calibration branch 201 includes a first voltage dividing calibration branch 2011 and a second voltage dividing calibration branch 2012. In some embodiments, the output voltage of the first voltage dividing calibration branch 2011 and the total resistance of the first voltage dividing calibration branch 2011 satisfy a linear regression equation, and the output voltage of the second voltage dividing calibration branch 2012 and the total resistance of the second voltage dividing calibration branch 2012 satisfy a linear regression equation. The output voltage of the calibration branch 202 and the total resistance of the calibration branch 202 satisfy a linear regression equation. The linear regression equation is Y=kx+b, wherein Y is the total resistance and x is the output voltage. Then, according to the first output voltage collected by the first voltage dividing calibration branch 2011 and the total resistance of the first voltage dividing calibration branch 2011, the first calibration parameter and the second calibration parameter, i.e., k and b, are obtained by substituting the above linear regression equation, and then the output voltage of the calibration circuit collected by the analog-to-digital converter is brought into the linear regression equation to determine the total resistance value (Rx+R0) of the calibration branch. The resistance value of the digital potentiometer is determined according to the total resistance value of the calibration branch 202 and the resistance value R0 of the auxiliary calibration resistor. For example, the digital potentiometer is first connected in series to the calibration circuit, the digital potentiometer is set to the minimum value, the third output voltage value of the output port ADC3 of the calibration branch is collected by the analog-to-digital converter, and the minimum resistance value of the digital potentiometer is calculated by substituting the equation Rx=kx+b-R0. The digital potentiometer is set to the maximum value, the fourth output voltage value of the output port ADC3 of the calibration branch is collected by the analog-to-digital converter, and the maximum resistance value of the digital potentiometer is calculated by substituting the equation Rx=kx+b-R0. The maximum resistance value and the minimum resistance value of the digital potentiometer are stored in the control module, and the digital potentiometer is driven for calibration.

[0050] In other optional embodiments of the present application, the relationship between the output voltage of the voltage dividing calibration branch 201 and the total resistance of the voltage dividing calibration branch 201, and the relationship between the output voltage of the calibration branch 202 and the total resistance of the calibration branch 202 can be a quadratic function relationship or other function relationship. The number of branches of the voltage dividing calibration branch 201 can be set according to the function relationship satisfied between the output voltage of the voltage dividing calibration branch 201 and the total resistance of the voltage dividing calibration branch 201, and the function relationship satisfied between the output voltage of the calibration branch 202 and the total resistance of the calibration branch 202, and the corresponding number of calibration parameters is determined.

[0051] With reference to the foregoing description, the calibration circuit 100 can be used for calibrating the digital potentiometer 101. The calibration circuit 100 includes a voltage dividing calibration branch 201 and a calibration branch 202. The voltage dividing calibration branch 201 includes a first voltage dividing branch 2011 and a second voltage dividing branch 2012. The calibration branch 202 includes a calibration branch 2021 and a calibration branch 2022. The calibration circuit 100 further includes an auxiliary calibration resistor R0, an analog-to-digital converter ADC, and a control module. The control module is connected to the digital potentiometer 101, the voltage dividing calibration branch 201, the calibration branch 202, the auxiliary calibration resistor R0, and the analog-to-digital converter ADC. Figure 2In some optional embodiments of the utility model, first voltage division calibration branch 2011 and second voltage division calibration branch 2012 are included; control module 103 is electrically connected with the first voltage division output end ADC1 of first voltage division calibration branch 2011 and the second voltage division output end ADC2 of second voltage division calibration branch 2012 respectively, and is used for determining first calibration parameter and second calibration parameter according to the first output voltage of first voltage division output end ADC1 and the second output voltage of second voltage division output end ADC2, the resistance of voltage division resistor of first voltage division calibration branch 2011, the resistance of voltage division resistor of second voltage division calibration branch 2012 and the first reference voltage and the second reference voltage accessed by first voltage division calibration branch 2011 and second voltage division calibration branch 2012;

[0052] The control module is used for calibrating the output voltage of the calibration branch according to the first calibration parameter and the second calibration parameter to obtain a calibration voltage, and calibrating the resistance of the digital potentiometer according to the calibration voltage, the first reference voltage, the second reference voltage and the resistance of the auxiliary calibration resistor R5. Wherein, Figure 2 In the figure, one end of first voltage division calibration branch 2011 is connected with the power supply, and the other end is connected with the ground; one end of second voltage division calibration branch 2012 is connected with the power supply, and the other end is connected with the ground; calibration branch 202 is connected in parallel with first voltage division calibration branch 2011 and second voltage division calibration branch 2012. Correspondingly, the first reference voltage is equal to the power supply voltage, and the second reference voltage is equal to the ground voltage.

[0053] The output voltage collected by the calibration branch 202 is calibrated to obtain a calibrated voltage through the first calibration parameter and the second calibration parameter, and the resistance of the digital potentiometer is determined according to the calibrated voltage, the first reference voltage, the second reference voltage and the resistance value of the auxiliary calibration resistor R5. In some embodiments, the output voltage of the first voltage division calibration branch 2011 obtained by the analog-to-digital converter of the control module satisfies a linear regression equation with the theoretical output voltage (i.e. the actual output voltage) of the first voltage division calibration branch 2011, and the output voltage of the second voltage division calibration branch 2012 obtained by the analog-to-digital converter of the control module satisfies a linear regression equation with the theoretical output voltage of the second voltage division calibration branch 2012. The output voltage of the calibration branch 202 obtained by the analog-to-digital converter of the control module satisfies a linear regression equation with the theoretical output voltage of the calibration branch 202. The linear regression equation is C=ax+d, where C is the theoretical output voltage, x is the output voltage obtained by the analog-to-digital converter of the control module, and the theoretical output voltage of the first voltage division calibration branch 2011 can be obtained by the control module according to the resistance value of the voltage division resistor in the first voltage division calibration branch 2011 and the first reference voltage and the second reference voltage. Then, the theoretical output voltage and the first output voltage of the first voltage division output terminal ADC1 obtained are substituted into the above linear regression equation. The same is true for the second voltage division calibration branch 2012. Thus, the first calibration parameter and the second calibration parameter (i.e. a and d) can be determined. Then, the output voltage of the calibration branch 202 obtained by the analog-to-digital converter is substituted into the linear regression equation to determine the theoretical output voltage of the calibration branch 202. Then, the calibration resistance of the digital potentiometer can be obtained according to the current of the calibration branch 201, which is equal to the theoretical output voltage and the resistance value of the auxiliary calibration resistor R5, and is equal to the ratio of the difference between the first reference voltage and the second reference voltage to the total resistance of the calibration branch 201.

[0054] In this way of determining the calibration resistance of the digital potentiometer, after the first calibration parameter and the second calibration parameter are determined, the digital potentiometer can be adjusted to the maximum resistance and the minimum resistance respectively to calibrate the maximum resistance and the minimum resistance respectively.

[0055] Reference continues to be made to Figure 2 In some optional embodiments of the utility model, the first voltage division calibration branch 2011 comprises a first voltage division resistor R1 and a second voltage division resistor R2 connected in series.

[0056] The second voltage division calibration branch 2012 comprises a third voltage division resistor R3 and a fourth voltage division resistor R4 connected in series.

[0057] The first voltage division calibration branch 2011 and the second voltage division calibration branch 2012 are connected in parallel, and the voltage division ratio of the first voltage division calibration branch 2011 and the second voltage division calibration branch 2012 is not equal.

[0058] The first voltage dividing resistor R1 and the second voltage dividing resistor R2 can be high-precision constant value resistors, and the third voltage dividing resistor R3 and the fourth voltage dividing resistor R4 can also be high-precision constant value resistors, and specifically can be 0.05% high-precision 1kΩ resistors. The first voltage dividing resistor R1 and the second voltage dividing resistor R2 and the third voltage dividing resistor R3 and the fourth voltage dividing resistor R4 form two high-precision voltage dividing resistor networks. The first voltage dividing calibration branch 2011 is connected in parallel with the second voltage dividing branch 2012, and the voltage dividing ratio of the first voltage dividing calibration branch 2011 and the second voltage dividing calibration branch 2012 is not equal, that is, the total resistance of the two voltage dividing calibration branches is not equal, and two parameters of a linear regression equation, that is, a first calibration parameter and a second calibration parameter, can be determined through the two voltage dividing calibration branches. The connection port 1 is electrically connected to one end of the digital potentiometer, and the second end of the digital potentiometer is electrically connected to the connection port 2 and grounded. Specifically, the resistance value of the voltage dividing resistor in each voltage dividing calibration branch can be set as needed to achieve different voltage dividing ratios, and the first output voltage of the first voltage dividing output end ADC1 collected by the port of the analog-to-digital converter and the second output voltage of the second voltage dividing output end ADC2 collected by the port of the analog-to-digital converter are used to determine the first calibration parameter and the second calibration parameter, so as to ensure the accuracy of the output voltage of the output end ADC3 of the calibration branch collected by the port of the analog-to-digital converter.

[0059] Figure 3 Another digital potentiometer calibration circuit schematic diagram is provided according to the embodiment of the utility model. In some optional embodiments of the utility model, as shown in Figure 3 , the voltage dividing calibration branch 301 further comprises a first switch S1, and the first switch S1 is connected in series with the voltage dividing resistor in the voltage dividing calibration branch 301; the first switch S1 is electrically connected to the control module 303, and the control module 303 is used for controlling the conduction of the first switch S1 in the calibration coefficient determination stage.

[0060] In some optional embodiments of the utility model, continuing to refer to Figure 3 , the calibration branch 302 further comprises a second switch S2, and the second switch S2 is connected in series between the auxiliary calibration resistor R5 and the connection port; the second switch S2 is electrically connected to the control module 303, and the control module 303 is used for controlling the conduction of the second switch S2 in the digital potentiometer calibration stage.

[0061] The first switch S1 is turned on in the calibration coefficient determination stage, and the calibration coefficient is determined before the digital potentiometer is calibrated. The second switch S2 is turned on when the digital potentiometer is calibrated, and after the first calibration parameter and the second calibration parameter are determined in the voltage division calibration branch 301, the circuit is switched to the calibration branch 302, so that the resistance value of the digital potentiometer is determined. By setting the first switch S1 and the second switch S2, multi-stage control of the circuit can be realized, different use requirements can be met, energy consumption of different circuits in a non-working state can be reduced, the circuit can be turned on or turned off according to actual needs, and unnecessary energy waste is avoided.

[0062] Figure 4 It is a structure diagram of a digital potentiometer calibration system according to an embodiment of the present application, comprising the digital potentiometer calibration circuit of any embodiment of the present application.

[0063] In some optional embodiments of the present application, as shown in Figure 4 It further comprises a third switch S3 and a fourth switch S4.

[0064] The third switch S3 is connected in series between the auxiliary calibration resistor and the connection port.

[0065] The first end of the fourth switch S4 is electrically connected with the connection port, and the second end of the fourth switch S4 is electrically connected with the functional circuit 403.

[0066] The third switch S3 and the fourth switch S4 are respectively electrically connected with the control module 401, and the control module 401 is further used for controlling the conduction of the third switch S3 in the digital potentiometer calibration stage; and the fourth switch S4 is controlled to be conducted in the normal working stage.

[0067] The third switch S3 is turned on in the digital potentiometer calibration stage, the circuit is switched to the digital potentiometer calibration circuit 402, and the digital calibration circuit calibration process described in the above embodiment is executed. The fourth switch S4 is turned on in the normal working stage, the circuit is switched to the functional circuit 403, and the digital potentiometer 404 works normally at this time. By setting the third switch S3 and the fourth switch S4, the system flexibility and convenience can be improved.

[0068] The digital potentiometer calibration system provided in the embodiment of the present application has the beneficial effects of the digital potentiometer calibration circuit described in any embodiment of the present application.

[0069] It should be understood that the various forms of processes shown above can be reordered, added to, or deleted from. For example, the steps described in the present application can be executed in parallel, in sequence, or in different orders, as long as the desired results of the technical solutions of the present application can be achieved, and the present application does not limit this.

[0070] The above detailed description does not constitute a limitation on the protection scope of the present application. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A digital potentiometer calibration circuit, characterized by, include: At least one voltage divider calibration branch, a calibration branch, and a control module; The voltage divider calibration branch includes at least two voltage divider resistors; The control module is electrically connected to the voltage divider output terminal of the voltage divider calibration branch, and is used to determine the calibration parameters based on the output voltage of the voltage divider calibration branch and the resistance value of the voltage divider resistor. The calibration branch includes an auxiliary calibration resistor and a connection port electrically connected to the auxiliary calibration resistor, the connection port being used to connect to the digital potentiometer; the output terminal of the calibration branch is electrically connected to the control module. The control module is also used to determine the calibration resistance of the digital potentiometer based on the output voltage of the calibration branch, the calibration parameters, and the resistance value of the auxiliary calibration resistor.

2. The digital potentiometer calibration circuit of claim 1, wherein, The connection port is connected in series with the auxiliary calibration resistor, and the common terminal of the connection port and the auxiliary calibration resistor serves as the output terminal of the calibration branch.

3. The digital potentiometer calibration circuit of claim 1 or 2, wherein, The calibration branch is connected in parallel with the voltage divider calibration branch.

4. The digital potentiometer calibration circuit of claim 3, wherein, Includes the first voltage divider calibration branch and the second voltage divider calibration branch; The control module is electrically connected to the first voltage divider output terminal of the first voltage divider calibration branch and the second voltage divider output terminal of the second voltage divider calibration branch, respectively, and is used to determine the first calibration parameter and the second calibration parameter based on the first output voltage of the first voltage divider output terminal and the second output voltage of the second voltage divider output terminal, the resistance value of the voltage divider resistor in the first voltage divider calibration branch and the resistance value of the voltage divider resistor in the second voltage divider calibration branch. The control module is used to calibrate the resistance of the digital potentiometer according to a set rule, wherein the set rule is: Rx = kx + b - R0; where k is the first calibration parameter, b is the second calibration parameter, Rx is the resistance value of the digital potentiometer, x is the output voltage of the calibration branch, and R0 is the resistance value of the auxiliary calibration resistor.

5. The digital potentiometer calibration circuit of claim 2, wherein, It includes a first voltage divider calibration branch and a second voltage divider calibration branch; the control module is electrically connected to the first voltage divider output terminal of the first voltage divider calibration branch and the second voltage divider output terminal of the second voltage divider calibration branch, respectively, and is used to determine the first calibration parameter and the second calibration parameter based on the first output voltage of the first voltage divider output terminal and the second output voltage of the second voltage divider output terminal, the resistance value of the voltage divider resistor of the first voltage divider calibration branch, the resistance value of the voltage divider resistor of the second voltage divider calibration branch, and the first reference voltage and the second reference voltage connected to the first voltage divider calibration branch and the second voltage divider calibration branch; The control module is used to calibrate the output voltage of the calibration branch according to the first calibration parameter and the second calibration parameter to obtain a calibration voltage, and to calibrate the resistance of the digital potentiometer according to the calibration voltage, the first reference voltage, the second reference voltage and the resistance value of the auxiliary calibration resistor.

6. A digital potentiometer calibration circuit according to claim 4 or 5, characterized in that The first voltage divider calibration branch includes a first voltage divider resistor and a second voltage divider resistor connected in series; The second voltage divider calibration branch includes a third voltage divider resistor and a fourth voltage divider resistor connected in series; The first voltage divider calibration branch is connected in parallel with the second voltage divider calibration branch, and the voltage division ratios of the first voltage divider calibration branch and the second voltage divider calibration branch are not equal.

7. The digital potentiometer calibration circuit of claim 6, wherein, The voltage division calibration branch further comprises a first switch connected in series with a voltage division resistor in the voltage division calibration branch; the first switch is electrically connected with the control module, and the control module is configured to control conduction of the first switch in a calibration coefficient determination stage.

8. The digital potentiometer calibration circuit of claim 7, wherein, The calibration branch further comprises a second switch connected in series between the auxiliary calibration resistor and the connection port; the second switch is electrically connected with the control module, and the control module is configured to control conduction of the second switch in a digital potentiometer calibration stage.

9. A digital potentiometer calibration system, characterized by, The digital potentiometer calibration circuit comprises any one of claims 1-8.

10. The digital potentiometer calibration system of claim 9, wherein, Further comprising a third switch and a fourth switch; The third switch is connected in series between the auxiliary calibration resistor and the connection port; A first end of the fourth switch is electrically connected with the connection port, and a second end of the fourth switch is electrically connected with a functional circuit; The third switch and the fourth switch are respectively electrically connected with the control module, and the control module is further configured to control conduction of the third switch in a digital potentiometer calibration stage and control conduction of the fourth switch in a normal working stage.

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