Temperature drift Wheatstone bridge model establishing method and device and computer equipment

Abstract

The invention discloses a temperature drift Wheatstone bridge model establishing method and device and computer equipment, and relates to the field of circuits. The method comprises the following steps: acquiring voltage data actually output by a Wheatstone bridge at different temperatures to obtain an actually measured voltage-temperature curve; according to the voltage-temperature curve, model parameters of a Wheatstone bridge model are obtained through calculation, and the model parameters comprise sensitivity drift parameters and zero drift parameters; and based on the sensitivity drift parameter and the zero drift parameter, establishing a model expression to obtain the Wheatstone bridge model. The Wheatstone bridge model constructed by the method not only can accurately measure the resistance, but also can keep the measurement precision and reliability under different temperature conditions.

Description

Technical Field

[0001] The present invention relates to the field of circuit technology, and in particular to a method, a device and a computer device for establishing a temperature drift Wheatstone bridge model. Background Art

[0002] The Wheatstone bridge is a circuit used to measure the change in resistance of a resistive element. It has two parallel resistor branches that act as a voltage divider for the excitation voltage. The nominal output of each resistor divider is half the excitation voltage. In the ideal case where no load is applied, the resistance change of the element is equal to zero, each voltage divider is at the same potential, and the output voltage of the differential bridge is zero. After the load is applied, one or more elements will change resistance, causing the output voltage of the differential bridge to change. By differentially measuring the differential bridge, the change can be accurately calculated. The Wheatstone bridge is often used in MEMS (Micro-Electro-Mechanical System) sensor devices. According to the piezoresistive effect, feedback signals are output for the state of the device to further achieve closed-loop control. The piezoresistive effect refers to the phenomenon that the resistance of certain materials changes when they are subjected to force. Using this effect, mechanical stress can be converted into electrical signals, thereby realizing the detection of physical quantities such as stress and pressure. Piezoresistive sensors are widely used in industry, automobiles, medical and other fields, and one of their core components is the Wheatstone bridge.

[0003] In modern electronic design automation (EDA), simulation and modeling are important links to ensure design reliability and performance. Verilog-A is a hardware description language used to simulate circuit behavior. It can accurately describe the electrical characteristics of analog circuits, making the design process more flexible, enabling rapid iteration, shortening the design cycle, and improving development efficiency. By modeling the Wheatstone bridge with Verilog-A, the Wheatstone bridge can be accurately simulated during the circuit design stage, its response under different working conditions can be predicted, and design parameters can be optimized. In integrated circuit design, it can be co-simulated with other analog circuit modules to verify the function and performance of the entire system.

[0004] The Wheatstone bridge model established in the related art usually does not consider the impact of temperature on the resistance and sensitivity of components, resulting in a decrease in measurement accuracy under changing temperature conditions and an inability to accurately predict the actual output at different temperatures. Therefore, the applicability of the existing model in high-precision measurements and temperature-sensitive applications is limited. Summary of the invention

[0005] In view of this, the present application provides a method and device for establishing a temperature drift Wheatstone bridge model, the main purpose of which is to solve the technical problem that the existing Wheatstone bridge model is affected by temperature, resulting in inaccurate measurement results.

[0006] According to a first aspect of the present invention, a method for establishing a temperature drift Wheatstone bridge model is provided, the method comprising:

[0007] Obtain the actual output voltage data of the Wheatstone bridge at different temperatures to obtain the measured voltage-temperature curve;

[0008] According to the voltage-temperature curve, model parameters of the Wheatstone bridge model are calculated, wherein the model parameters include a sensitivity drift parameter and a zero drift parameter;

[0009] A model expression is established based on the sensitivity drift parameter and the zero drift parameter to obtain the Wheatstone bridge model.

[0010] Further, the calculating of model parameters of the Wheatstone bridge model according to the voltage-temperature curve includes:

[0011] Fitting the voltage-temperature curve to obtain a relationship between the output voltage and temperature of the Wheatstone bridge;

[0012] According to the relationship between the output voltage and the temperature and the calculated relationship between the piezoresistive sensitivity and the output voltage, the relationship between the piezoresistive sensitivity and the temperature is obtained;

[0013] According to the relationship between piezoresistive sensitivity and temperature, the sensitivity drift parameter is calculated;

[0014] According to the voltage-temperature curve, the process error of each resistor in the Wheatstone bridge is measured to obtain the zero drift parameter.

[0015] Furthermore, the relationship between the piezoresistive sensitivity and temperature includes:

[0016] S=a 0 -a(TT 0 );

[0017] Where S is the piezoresistive sensitivity, a 0 is the starting value of voltage, a is the temperature drift coefficient, T is the current temperature, T 0 is the operating temperature.

[0018] Furthermore, the sensitivity drift parameter is calculated based on the relationship between the piezoresistive sensitivity and the temperature, including:

[0019] According to the relationship between piezoresistive sensitivity and temperature, the actual sensitivity corresponding to the current temperature is calculated;

[0020] Calculate a sensitivity drift parameter according to the actual sensitivity;

[0021] The calculation formulas of the actual sensitivity and the sensitivity drift parameter are as follows:

[0022]

[0023] Among them, sen_temp is the actual sensitivity, a 0 is the voltage starting value, a is the temperature drift coefficient, T is the current temperature, R_sen is the sensitivity drift parameter, and V(sig) is the driving signal.

[0024] Furthermore, the establishing of a model expression based on the sensitivity drift parameter and the zero drift parameter to obtain the Wheatstone bridge model includes:

[0025] Construct the arms of a Wheatstone bridge, where each arm contains a resistor;

[0026] Based on the sensitivity drift parameter and the zero drift parameter, each resistor is compensated and a resistance compensation expression is established;

[0027] Based on the resistance compensation expression, the voltage corresponding to each resistor is calculated, and a model expression is established to obtain the Wheatstone bridge model.

[0028] Furthermore, the voltage corresponding to each resistor is calculated based on the resistance compensation expression, and the model expression is established, including:

[0029]

[0030] Among them, R1 is the first resistor, V1 is the voltage corresponding to the first resistor, I1 is the current corresponding to the first resistor, delta1 is the zero drift parameter of the first resistor, R2 is the second resistor, V2 is the voltage corresponding to the second resistor, I2 is the current corresponding to the second resistor, delta2 is the zero drift parameter of the second resistor, R3 is the third resistor, V3 is the voltage corresponding to the third resistor, I3 is the current corresponding to the third resistor, delta3 is the zero drift parameter of the third resistor, R4 is the fourth resistor, V4 is the voltage corresponding to the fourth resistor, I4 is the current corresponding to the fourth resistor, delta4 is the zero drift parameter of the fourth resistor, and R_sen is the sensitivity drift parameter.

[0031] Further, after obtaining the Wheatstone bridge model, the method further includes:

[0032] Performing simulation based on the Wheatstone bridge model to obtain a simulated voltage-temperature curve;

[0033] Based on the simulated voltage-temperature curve, the temperature drift characteristic of the Wheatstone bridge is verified.

[0034] According to a second aspect of the present invention, there is provided a device for establishing a temperature drift Wheatstone bridge model, the device comprising:

[0035] A data processing module is used to obtain the voltage data actually output by the Wheatstone bridge at different temperatures to obtain a measured voltage-temperature curve;

[0036] A parameter calculation module, used to calculate the model parameters of the Wheatstone bridge model according to the voltage-temperature curve, wherein the model parameters include a sensitivity drift parameter and a zero drift parameter;

[0037] The model building module is used to establish a model expression based on the sensitivity drift parameter and the zero drift parameter to obtain the Wheatstone bridge model.

[0038] According to a third aspect of the present invention, there is provided a storage medium having a computer program stored thereon, wherein when the program is executed by a processor, the above-mentioned method for establishing a temperature drift Wheatstone bridge model is implemented.

[0039] According to a fourth aspect of the present invention, there is provided a computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned method for establishing a temperature drift Wheatstone bridge model when executing the program.

[0040] The present invention provides a method, device, storage medium and computer equipment for establishing a temperature drift Wheatstone bridge model. First, the voltage data actually output by the Wheatstone bridge at different temperatures is obtained to obtain the measured voltage-temperature curve; then, according to the voltage-temperature curve, the model parameters of the Wheatstone bridge model are calculated, wherein the model parameters include sensitivity drift parameters and zero drift parameters; finally, based on the sensitivity drift parameters and the zero drift parameters, a model expression is established to obtain the Wheatstone bridge model. This application takes into account the zero drift and sensitivity drift characteristics of the Wheatstone bridge, and uses Verilog A to realize the construction of the Wheatstone bridge model. The Wheatstone bridge model constructed in this way can not only accurately measure resistance, but also maintain the accuracy and reliability of measurement under different temperature conditions.

[0041] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0043] Figure 1 A schematic circuit diagram of a basic Wheatstone bridge provided by an embodiment of the present invention is shown;

[0044] Figure 2 A schematic flow chart of a method for establishing a temperature drift Wheatstone bridge model provided by an embodiment of the present invention is shown;

[0045] Figure 3 A schematic diagram of a voltage-temperature curve of a Wheatstone bridge measured in an embodiment of the present invention is shown;

[0046] Figure 4 A schematic diagram of a voltage-temperature curve of a simulated Wheatstone bridge model provided by an embodiment of the present invention is shown;

[0047] Figure 5 A schematic structural diagram of a device for establishing a temperature drift Wheatstone bridge model provided by an embodiment of the present invention is shown;

[0048] Figure 6 A schematic structural diagram of a computer device for implementing a method for establishing a temperature drift Wheatstone bridge model provided by an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0049] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. In the various embodiments shown below, the first, second and various digital numbers are only used to distinguish for the convenience of description and are not used to limit the scope of the embodiments of the present application.

[0050] Wheatstone bridges are often used in MEMS (Micro-Electro-Mechanical System) sensor devices. Based on the piezoresistive effect, feedback signals are output on the device status to further achieve closed-loop control. The piezoresistive effect refers to the phenomenon that the resistance of certain materials changes when they are subjected to force. By using this effect, mechanical stress can be converted into electrical signals, thereby realizing the detection of physical quantities such as stress and pressure. Piezoresistive sensors are widely used in industry, automobiles, medical and other fields, and one of their core components is the Wheatstone bridge.

[0051] The Wheatstone bridge is a circuit used to measure the change in resistance of a resistive element. It has two sets of parallel resistor branches that act as an excitation voltage V EXCITATIONThe nominal output of each resistor divider is the excitation voltage V EXCITATION When no load is applied, the resistance change ΔR of the component is equal to zero. Assume that there is an ideal system such as Figure 1 As shown in FIG. 1 , a basic configuration circuit of a Wheatstone bridge is provided, in which the nominal resistance of each element is R, each voltage divider is at the same potential, and the output voltage V of the differential bridge is out When a load is applied, one or more components will change resistance so that ΔR≠0Ω, resulting in a change in the output voltage of the differential bridge, which can be accurately calculated by taking a differential measurement of the differential bridge.

[0052] In modern electronic design automation (EDA), simulation and modeling are important links to ensure design reliability and performance. Verilog-A is a hardware description language used to simulate circuit behavior. It can accurately describe the electrical characteristics of analog circuits, making the design process more flexible, enabling rapid iteration, shortening the design cycle, and improving development efficiency. By modeling the Wheatstone bridge with Verilog-A, the Wheatstone bridge can be accurately simulated during the circuit design stage, its response under different working conditions can be predicted, and design parameters can be optimized. In integrated circuit design, it can be co-simulated with other analog circuit modules to verify the function and performance of the entire system.

[0053] The Wheatstone bridge model established in the related art usually does not consider the impact of temperature on the resistance and sensitivity of components, resulting in a decrease in measurement accuracy under changing temperature conditions and an inability to accurately predict the actual output at different temperatures. Therefore, the applicability of the existing model in high-precision measurements and temperature-sensitive applications is limited.

[0054] Based on the above problems, the present application embodiment provides a method for establishing a temperature drift Wheatstone bridge model. In one embodiment, Figure 2 As shown, the method comprises the following steps:

[0055] 101. Obtain the actual output voltage data of the Wheatstone bridge at different temperatures to obtain the measured voltage-temperature curve.

[0056] 102. Calculate model parameters of a Wheatstone bridge model according to the voltage-temperature curve, wherein the model parameters include a sensitivity drift parameter and a zero drift parameter.

[0057] 103. Establish a model expression based on the sensitivity drift parameter and the zero drift parameter to obtain the Wheatstone bridge model.

[0058] In this embodiment, the Wheatstone bridge in the MEMS can be measured to obtain a voltage-temperature curve. Specifically, the temperature range of the measurement can be preset, for example, -20 degrees to 80 degrees, and the output voltage data of the Wheatstone bridge at different temperatures within the preset temperature range can be collected, and the voltage-temperature curve can be drawn based on the corresponding output voltage data at different temperatures. In one example, the voltage-temperature curve can be as follows: Figure 3 shown.

[0059] After obtaining the voltage-temperature curve, the voltage-temperature curve is fitted to obtain the relationship between voltage and temperature, and the relationship between piezoresistive sensitivity and temperature is obtained based on the calculated relationship between the output voltage of the Wheatstone bridge and the piezoresistive sensitivity, and then the sensitivity drift parameter is calculated based on the relationship between the piezoresistive sensitivity and temperature. And according to the voltage-temperature curve, the zero drift parameter of each resistor in the Wheatstone bridge caused by the process error is obtained. According to the zero drift parameter and the sensitivity drift parameter, the model parameters of the Wheatstone bridge model are obtained.

[0060] In this embodiment, the zero drift characteristic and sensitivity drift characteristic of the Wheatstone bridge are taken into consideration, and the temperature drift of the Wheatstone bridge is compensated by using the zero drift parameter and the sensitivity drift parameter. Among them, the zero drift characteristic refers to the zero position output generated due to the fact that the resistance values ​​on the four bridge arms of the Wheatstone bridge are not completely equal due to the manufacturing process and other reasons. Sensitivity drift refers to the change in the amount of resistance change under pressure caused by the change in the piezoresistance coefficient with temperature. Therefore, when establishing the Wheatstone bridge model, the sensitivity drift parameter and the zero drift parameter are introduced into the model expression to construct a temperature drift Wheatstone bridge model.

[0061] The present invention provides a method, device, storage medium and computer equipment for establishing a temperature drift Wheatstone bridge model. First, the voltage data actually output by the Wheatstone bridge at different temperatures is obtained to obtain the measured voltage-temperature curve; then, according to the voltage-temperature curve, the model parameters of the Wheatstone bridge model are calculated, wherein the model parameters include sensitivity drift parameters and zero drift parameters; finally, based on the sensitivity drift parameters and the zero drift parameters, a model expression is established to obtain the Wheatstone bridge model. The present application takes into account the zero drift and sensitivity drift characteristics of the Wheatstone bridge, and uses the Verilog A language to realize the construction of the Wheatstone bridge model. The Wheatstone bridge model constructed in this way can not only accurately measure resistance, but also maintain the accuracy and reliability of measurement under different temperature conditions.

[0062] Further, in order to fully illustrate the implementation process of this embodiment, the specific implementation method of the above embodiment is refined and expanded below. Specifically, in the above embodiment, Figure 1Taking the Wheatstone bridge shown in the figure as an example, the output voltage of the Wheatstone bridge is calculated by the voltage difference of the resistors on both sides, and the expression is as follows:

[0063]

[0064] In formula (1), V out is the output voltage of the Wheatstone bridge, V EXCIATION is the excitation voltage, R is the resistance of each resistor element, and ΔR is the change in resistance.

[0065] According to formula (1), an electrical model of a Wheatstone bridge can be established. In the use of related Wheatstone bridges, a constant current source is often used to power the Wheatstone bridge. The expression of the output voltage of the Wheatstone bridge can be transformed into formula (2):

[0066] V out =I in ΔR; (2)

[0067] In formula (2), I in is the current of the constant current source.

[0068] In reality, the resistor elements in the Wheatstone bridge are usually semiconductor materials with temperature-sensitive properties. The working environment temperature will affect the resistance value, resulting in errors in the output of the sensor with the Wheatstone bridge as the core element. For embedded piezoresistors, temperature drift includes zero-point temperature drift and sensitivity temperature drift. Zero-point temperature drift is mainly caused by the manufacturing process, which causes the resistance of each resistor to be not completely equal. Sensitivity drift includes the change in the resistance of the bridge arm caused by temperature changes, recorded as ΔR t , and the change in the piezoresistance coefficient caused by temperature, which in turn causes the change in resistance under pressure, recorded as ΔR r Based on this, the calculation formula for the output voltage of the temperature drifted Wheatstone bridge can be expressed as:

[0069]

[0070] In formula (3), V out is the output voltage of the Wheatstone bridge, V ref is the supply voltage, R is the nominal resistance of the Wheatstone bridge, and ΔR is the change in resistance caused by the load (pressure). t are canceled, and ΔR t Usually much smaller than R, so ΔR t can be ignored. Then the expression of the output voltage of the Wheatstone bridge is approximately:

[0071]

[0072] Based on this, in the embodiment of the present application, the sensitivity temperature drift is mainly caused by the change of the piezoresistance coefficient with temperature. <100> Surface oriented diffusion doping on thin films <110> The piezoresistance coefficient of the P-type resistor in the crystal direction is approximately:

[0073] π l =-π t =π 44 / 2; (5)

[0074] Among them, π l is the longitudinal piezoresistance coefficient, π t is the lateral piezoresistance coefficient, π 44 is the piezoresistance coefficient in the crystal axis direction. According to formula (5), the piezoresistance change is:

[0075]

[0076] In formula (6), σ x is the lateral stress of the resistor, which is proportional to the pressure of the silicon film, σ y is the stress in the longitudinal direction of the resistor, which is proportional to the pressure on the silicon film.

[0077] According to formula (4) and formula (6), the calculation formulas for the output voltage and piezoresistance sensitivity of the Wheatstone bridge are as follows:

[0078]

[0079] Where S is the piezoresistive sensitivity. Further, the piezoresistive sensitivity can be expressed as:

[0080]

[0081] According to formula (9), it can be seen that the piezoresistive sensitivity is inversely proportional to the temperature.

[0082] In one embodiment, in step 102, the model parameters of the Wheatstone bridge model are calculated according to the voltage-temperature curve, which can be specifically achieved in the following manner: fitting the voltage-temperature curve to obtain a relationship between the output voltage and temperature of the Wheatstone bridge; obtaining a relationship between the piezoresistive sensitivity and the temperature according to the relationship between the output voltage and the temperature and the calculated relationship between the piezoresistive sensitivity and the output voltage; calculating a sensitivity drift parameter according to the relationship between the piezoresistive sensitivity and the temperature; and measuring the process error of each resistor in the Wheatstone bridge according to the voltage-temperature curve to obtain a zero drift parameter.

[0083] In the above embodiment, the voltage-temperature curve measured by the Wheatstone bridge is as follows: Figure 3As shown, the voltage-temperature curve is fitted, and the relationship between the Wheatstone bridge and temperature is obtained as follows:

[0084] V out =V 0 -k(TT 0 );(10)

[0085] In formula (10), V out is the output voltage of the Wheatstone bridge, V 0 is the corresponding voltage value, k is the coefficient, T is the current temperature, T 0 is the operating temperature. The coefficient k can be calculated by the output voltage V out Taking the derivative with respect to temperature T we get:

[0086] Then, based on formula (10) and the calculated relationship between the output voltage of the Wheatstone bridge and the piezoresistive sensitivity, the relationship between the piezoresistive sensitivity and the temperature can be obtained:

[0087] S=a 0 -a(TT 0 );(11)

[0088] Where S is the piezoresistive sensitivity, a 0 is the starting value of voltage, a is the temperature drift coefficient, T is the current temperature, T 0 is the operating temperature.

[0089] According to formula (11), the sensitivity drift parameter can be calculated.

[0090] In one embodiment, the sensitivity drift parameter is calculated based on the relationship between the piezoresistive sensitivity and the temperature, which can be specifically implemented in the following manner: according to the relationship between the piezoresistive sensitivity and the temperature, the actual sensitivity corresponding to the current temperature is calculated; according to the actual sensitivity, the sensitivity drift parameter is calculated; the calculation formulas of the actual sensitivity and the sensitivity drift parameter are as follows:

[0091] sen_temp=a 0 -a*T; (12)

[0092] R_sen=V(sig)*sen_temp; (13)

[0093] Among them, sen_temp is the actual sensitivity, a 0 is the voltage starting value, a is the temperature drift coefficient, T is the current temperature, R_sen is the sensitivity drift parameter, and V(sig) is the driving signal.

[0094] After obtaining the zero drift parameter and sensitivity drift parameter of each resistor, the temperature drift is compensated by the zero drift parameter and the sensitivity drift parameter to construct a Wheatstone bridge model. In one embodiment, the specific construction method of the Wheatstone bridge model is as follows: construct each bridge arm of the Wheatstone bridge, wherein each bridge arm includes a resistor; based on the sensitivity drift parameter and the zero drift parameter, each resistor is compensated to establish a resistance compensation expression; based on the resistance compensation expression, the voltage corresponding to each resistor is calculated, a model expression is established, and the Wheatstone bridge model is obtained.

[0095] According to the analysis of the temperature drift of the Wheatstone bridge and the formula of the output voltage of the Wheatstone bridge in the above embodiment, each resistor in the Wheatstone bridge is compensated by the temperature drift parameter and the sensitivity drift parameter to obtain a resistance compensation expression, and a Wheatstone bridge model is constructed based on the resistance compensation expression. The resistance compensation expression of each resistor in the Wheatstone bridge is:

[0096]

[0097] Among them, R1 is the first resistor, delta1 is the zero drift parameter of the first resistor, R2 is the second resistor, delta2 is the zero drift parameter of the second resistor, R3 is the third resistor, delta3 is the zero drift parameter of the third resistor, R4 is the fourth resistor, delta4 is the zero drift parameter of the fourth resistor, and R_sen is the sensitivity drift parameter.

[0098] And, in the embodiment of the present application, based on the resistance compensation expression, the voltage corresponding to each resistor is calculated and a model expression is established, including:

[0099]

[0100] Among them, V1 is the voltage corresponding to the first resistor, I1 is the current corresponding to the first resistor, V2 is the voltage corresponding to the second resistor, I2 is the current corresponding to the second resistor, V3 is the voltage corresponding to the third resistor, I3 is the current corresponding to the third resistor, V4 is the voltage corresponding to the fourth resistor, and I4 is the current corresponding to the fourth resistor.

[0101] In a specific example, based on the above embodiment, part of the code of the temperature drift Wheatstone bridge model constructed by Verilog A language is as follows:

[0102] 1.include "constants.vams" / / A file named "constants.vams" is included, which may define some constants or parameters for use in subsequent codes.

[0103] 2.include "disciplines.vams" / / A file named "disciplines.vams" is included, which may define some model or behavioral specifications for use by subsequent codes.

[0104] 3.module bridge(VDD,sig,von,vop,GND); / / defines a module named "bridge" with five ports: VDD, sig, von, vop and GND. Among them, VDD and GND are input ports, sig is an input port, and von and vop are output ports.

[0105] 4.input sig; / / Declares an input port named sig.

[0106] 5.input VDD,GND; / / Two input ports, VDD and GND, are declared.

[0107] 6.output von,vop; / / Declares two output ports, von and vop.

[0108] 7.electrical sig,VDD,GND,von,vop; / / The electrical variables sig, VDD, GND, von and vop are declared, where von is the negative end of the output of the Wheatstone bridge and vop is the positive end of the output.

[0109] 8.branch(VDD,von)res1; / / Declares a branch (bridge arm) named res1, connecting VDD and von.

[0110] 9.parameter real R1=X; / / defines a real parameter named R1 (first resistor), the default value is X.

[0111] 10.branch(VDD,vop)res2; / / Declares a branch (bridge arm) named res2, connecting VDD and vop.

[0112] 11.parameter real R2=X; / / defines a real parameter named R2 (second resistor), the default value is X.

[0113] 12.branch(von,GND)res3; / / Declares a branch (bridge arm) named res3, connecting von and GND.

[0114] 13.parameter real R3=X; / / defines a real parameter named R3 (the third resistor), the default value is X.

[0115] 14.branch(vop,GND)res4; / / Declares a branch (bridge arm) named res4, connecting vop and GND.

[0116] 15.parameter real R4=X; / / defines a real parameter named R4 (the fourth resistor), the default value is X.

[0117] 16. parameter real sen = A; / / defines a real number parameter named sen, the default value of which is A, i.e. a in the above embodiment.

[0118] 17.parameter real delta1=B; / / Defines a real number parameter named delta1, with the default value of B.

[0119] 18.parameter real delta2 = B; / / defines a real number parameter named delta2, the default value is B.

[0120] 19.parameter real delta3=B; / / Defines a real number parameter named delta3, with the default value of B.

[0121] 20.parameter real delta4=B; / / Defines a real number parameter named delta4, with the default value of B.

[0122] 22.real sen_temp; / / Declares a real number variable named sen_temp.

[0123] 23.real temp; / / Declares a real number variable named temp.

[0124] 24.real R_sen; / / Declares a real number variable named R_sen.

[0125] 25.analog begin / / Enter the analog statement block, which is used to describe the analog behavior.

[0126] 26.temp=Stemperature; / / Get the current temperature, that is, the temperature T in the above embodiment, and assign it to the temp variable.

[0127] 27.sen_temp=C-sen*temp; / / Calculate the value of sen_temp variable according to temperature. sen_temp represents the actual sensitivity after temperature change, which is used to reflect sensitivity drift. C is a parameter constant, which is the starting value of voltage output, i.e., a in the above embodiment. 0 .

[0128] 28. R_sen = V(sig)*sen_temp; / / Calculate the value of R_sen variable. Indicates the value obtained under the driving of sig signal.

[0129] 29.V(res1)<+I(res1)*(R1*(1+delta1)-R_sen);

[0130] V(res2)<+I(res2)*(R2*(1+delta2)+R_sen);

[0131] V(res3)<+I(res3)*(R3*(1+delta3)+R_sen);

[0132] V(res4)<+I(res4)*(R4*(1+delta4)-R_sen); / / Assign values ​​to each branch (bridge arm). (1+delta1) to (1+delta4) represent the error of resistors R1 to R4 respectively. This error is the zero point drift caused by process and temperature.

[0133] 30.end` / / End the simulation statement block.

[0134] 31.`Endmodule` / / End module definition.

[0135] In one embodiment, after the temperature drift Wheatstone bridge model is established, simulation is performed based on the Wheatstone bridge model to obtain a simulated voltage-temperature curve; based on the simulated voltage-temperature curve, the temperature drift characteristics of the Wheatstone bridge are verified. Specifically, a voltage value of 1V can be given to the sig signal, indicating that a constant pressure is given to the Wheatstone bridge to stabilize the output. Due to temperature changes, the voltage output by the Wheatstone bridge will change. In one example, the simulation results are as follows: Figure 4 It can be seen from the voltage-temperature curve in the simulation results that the output voltage of the Wheatstone bridge model constructed in the embodiment of the present application satisfies the temperature drift characteristic.

[0136] The method for establishing a temperature drift Wheatstone bridge model provided in the embodiment of the present application starts from a more accurate physical output mechanism and temperature drift mechanism, and adds zero drift parameters and sensitivity drift parameters to compensate for temperature drift on the basis of the original Wheatstone bridge model. The temperature drift Wheatstone bridge model obtained based on this has a more accurate output result in circuit simulation, which is beneficial to a more accurate MEMS sensor feedback circuit design.

[0137] Further, as Figure 2 The specific implementation of the method shown in the embodiment provides a device for establishing a temperature drift Wheatstone bridge model, such as Figure 5 As shown, the device includes: a data processing module 31, a parameter calculation module 32, and a model construction module 33.

[0138] The data processing module 31 can be used to obtain the voltage data actually output by the Wheatstone bridge at different temperatures to obtain the measured voltage-temperature curve;

[0139] A parameter calculation module 32, which can be used to calculate the model parameters of the Wheatstone bridge model according to the voltage-temperature curve, wherein the model parameters include a sensitivity drift parameter and a zero drift parameter;

[0140] The model building module 33 can be used to establish a model expression based on the sensitivity drift parameter and the zero drift parameter to obtain the Wheatstone bridge model.

[0141] In a specific application scenario, the model parameters of the Wheatstone bridge model are calculated based on the voltage-temperature curve. The parameter calculation module 32 can be specifically used to fit the voltage-temperature curve to obtain the relationship between the output voltage and temperature of the Wheatstone bridge; the relationship between the piezoresistance sensitivity and the temperature is obtained based on the relationship between the output voltage and the temperature and the calculated relationship between the piezoresistance sensitivity and the output voltage; the sensitivity drift parameter is calculated based on the relationship between the piezoresistance sensitivity and the temperature; the process error of each resistor in the Wheatstone bridge is measured based on the voltage-temperature curve to obtain the zero drift parameter. The relationship between the piezoresistance sensitivity and the temperature includes: S = a 0 -a(TT 0 ), where S is the piezoresistive sensitivity, a 0 is the starting value of voltage, a is the temperature drift coefficient, T is the current temperature, T 0 is the operating temperature.

[0142] In a specific application scenario, the sensitivity drift parameter is calculated based on the relationship between the piezoresistive sensitivity and the temperature. The parameter calculation module 32 can be specifically used to calculate the actual sensitivity corresponding to the current temperature based on the relationship between the piezoresistive sensitivity and the temperature; the sensitivity drift parameter is calculated based on the actual sensitivity; the calculation formulas of the actual sensitivity and the sensitivity drift parameter are as follows:

[0143]

[0144] Among them, sen_temp is the actual sensitivity, a 0 is the voltage starting value, a is the temperature drift coefficient, T is the current temperature, R_sen is the sensitivity drift parameter, and V(sig) is the driving signal.

[0145] In a specific application scenario, based on the sensitivity drift parameter and the zero drift parameter, a model expression is established to obtain the Wheatstone bridge model. The model establishment module 33 can be specifically used to construct each bridge arm of the Wheatstone bridge, wherein each bridge arm includes a resistor; based on the sensitivity drift parameter and the zero drift parameter, each resistor is compensated to establish a resistor compensation expression; based on the resistor compensation expression, the voltage corresponding to each resistor is calculated, and a model expression is established to obtain the Wheatstone bridge model.

[0146] In a specific application scenario, the model building module 33 calculates the voltage corresponding to each resistor based on the resistance compensation expression and builds a model expression, including:

[0147]

[0148] Among them, R1 is the first resistor, V1 is the voltage corresponding to the first resistor, I1 is the current corresponding to the first resistor, delta1 is the zero drift parameter of the first resistor, R2 is the second resistor, V2 is the voltage corresponding to the second resistor, I2 is the current corresponding to the second resistor, delta2 is the zero drift parameter of the second resistor, R3 is the third resistor, V3 is the voltage corresponding to the third resistor, I3 is the current corresponding to the third resistor, delta3 is the zero drift parameter of the third resistor, R4 is the fourth resistor, V4 is the voltage corresponding to the fourth resistor, I4 is the current corresponding to the fourth resistor, delta4 is the zero drift parameter of the fourth resistor, and R_sen is the sensitivity drift parameter.

[0149] In a specific application scenario, the device also includes a simulation verification module 34, which can be used to perform simulation based on the Wheatstone bridge model after obtaining the Wheatstone bridge model to obtain a simulated voltage-temperature curve; based on the simulated voltage-temperature curve, verify the temperature drift characteristics of the Wheatstone bridge.

[0150] It should be noted that for other corresponding descriptions of the functional units involved in the temperature drift Wheatstone bridge model establishment device provided in this embodiment, reference can be made to Figure 2 The corresponding description in will not be repeated here. Figure 2 The method shown in the embodiment also provides a storage medium on which a computer program is stored. When the program is executed by a processor, the above-mentioned Figure 2 The temperature drift Wheatstone bridge model is shown in Figure 1.

[0151] Based on this understanding, the technical solution of the present application can be embodied in the form of a software product. The software product to be identified can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.), including a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each implementation scenario of the present application.

[0152] Based on the above Figure 2 The method shown, and Figure 5 The temperature drift Wheatstone bridge model establishment device embodiment shown in the figure is used to achieve the above-mentioned purpose. Figure 6 As shown, this embodiment also provides a computer device for establishing a temperature drift Wheatstone bridge model, which can be a personal computer, a server, a smart phone, a tablet computer, a smart watch, or other network devices, etc. The computer device includes a storage medium and a processor; the storage medium is used to store a computer program and an operating system; the processor is used to execute the computer program to implement the above-mentioned Figure 2 The method shown.

[0153] Optionally, the computer device may further include an internal memory, a communication interface, a network interface, a camera, a radio frequency (RF) circuit, a sensor, an audio circuit, a WI-FI module, a display, an input device such as a keyboard, etc. Optionally, the communication interface may also include a USB interface, a card reader interface, etc. The network interface may optionally include a standard wired interface, a wireless interface (such as a WI-FI interface), etc.

[0154] Those skilled in the art will appreciate that the computer device structure established by the temperature drift Wheatstone bridge model provided in this embodiment does not constitute a limitation on the computer device, and may include more or fewer components, or a combination of certain components, or different component arrangements.

[0155] The storage medium may also include an operating system and a network communication module. The operating system is a program that manages the above-mentioned computer device hardware and the software resources to be identified, and supports the operation of the information processing program and other software and / or programs to be identified. The network communication module is used to realize the communication between the components inside the storage medium, and the communication with other hardware and software in the information processing computer device.

[0156] Through the description of the above implementation methods, those skilled in the art can clearly understand that the present application can be implemented by means of software plus a necessary general hardware platform, or by hardware. By applying the technical solution of the present application, first, the voltage data actually output by the Wheatstone bridge at different temperatures is obtained to obtain the measured voltage-temperature curve; then, according to the voltage-temperature curve, the model parameters of the Wheatstone bridge model are calculated, wherein the model parameters include sensitivity drift parameters and zero drift parameters; finally, based on the sensitivity drift parameters and the zero drift parameters, a model expression is established to obtain the Wheatstone bridge model. Compared with the prior art, the present application takes into account the zero drift and sensitivity drift characteristics of the Wheatstone bridge, and uses Verilog A to realize the construction of the Wheatstone bridge model. The Wheatstone bridge model constructed in this way can not only accurately measure resistance, but also maintain the accuracy and reliability of measurement under different temperature conditions.

[0157] Those skilled in the art will appreciate that the accompanying drawings are only schematic diagrams of a preferred implementation scenario, and the modules or processes in the accompanying drawings are not necessarily necessary for implementing the present application. Those skilled in the art will appreciate that the modules in the devices in the implementation scenario can be distributed in the devices of the implementation scenario according to the description of the implementation scenario, or can be changed accordingly and located in one or more devices different from the present implementation scenario. The modules of the above-mentioned implementation scenario can be combined into one module, or can be further split into multiple submodules.

[0158] The above serial numbers of this application are only for description and do not represent the advantages and disadvantages of the implementation scenarios. The above disclosure is only a few specific implementation scenarios of this application, but this application is not limited to them, and any changes that can be thought of by technicians in this field should fall within the scope of protection of this application.

Claims

1. A method for establishing a temperature drift Wheatstone bridge model, characterized in that: The method comprises: Obtain the actual output voltage data of the Wheatstone bridge at different temperatures to obtain the measured voltage-temperature curve; According to the voltage-temperature curve, model parameters of the Wheatstone bridge model are calculated, wherein the model parameters include a sensitivity drift parameter and a zero drift parameter; Based on the sensitivity drift parameter and the zero drift parameter, a model expression is established to obtain the Wheatstone bridge model.

2. The method according to claim 1, characterized in that: The step of calculating the model parameters of the Wheatstone bridge model according to the voltage-temperature curve includes: Fitting the voltage-temperature curve to obtain a relationship between the output voltage and temperature of the Wheatstone bridge; According to the relationship between the output voltage and the temperature and the calculated relationship between the piezoresistive sensitivity and the output voltage, the relationship between the piezoresistive sensitivity and the temperature is obtained; According to the relationship between piezoresistive sensitivity and temperature, the sensitivity drift parameter is calculated; According to the voltage-temperature curve, the process error of each resistor in the Wheatstone bridge is measured to obtain the zero drift parameter.

3. The method according to claim 2, characterized in that The relationship between the piezoresistive sensitivity and temperature includes: S = a0-a(T-T0); Among them, S is the piezoresistive sensitivity, a0 is the starting voltage value, a is the temperature drift coefficient, T is the current temperature, and T0 is the operating temperature.

4. The method according to claim 3, characterized in that The sensitivity drift parameter is calculated based on the relationship between the piezoresistive sensitivity and the temperature, including: According to the relationship between piezoresistive sensitivity and temperature, the actual sensitivity corresponding to the current temperature is calculated; Calculate a sensitivity drift parameter according to the actual sensitivity; The calculation formulas for the actual sensitivity and the sensitivity drift parameter are as follows: Among them, sen_temp is the actual sensitivity, a0 is the voltage starting value, a is the temperature drift coefficient, T is the current temperature, R_sen is the sensitivity drift parameter, and V(sig) is the driving signal.

5. The method according to claim 1, characterized in that The step of establishing a model expression based on the sensitivity drift parameter and the zero drift parameter to obtain the Wheatstone bridge model comprises: Construct the arms of a Wheatstone bridge, where each arm contains a resistor; Based on the sensitivity drift parameter and the zero drift parameter, each resistor is compensated and a resistance compensation expression is established; Based on the resistance compensation expression, the voltage corresponding to each resistor is calculated, and a model expression is established to obtain the Wheatstone bridge model.

6. The method according to claim 1, characterized in that The method of calculating the voltage corresponding to each resistor based on the resistance compensation expression and establishing the model expression includes: Among them, R1 is the first resistor, V1 is the voltage corresponding to the first resistor, I1 is the current corresponding to the first resistor, delta1 is the zero drift parameter of the first resistor, R2 is the second resistor, V2 is the voltage corresponding to the second resistor, I2 is the current corresponding to the second resistor, delta2 is the zero drift parameter of the second resistor, R3 is the third resistor, V3 is the voltage corresponding to the third resistor, I3 is the current corresponding to the third resistor, delta3 is the zero drift parameter of the third resistor, R4 is the fourth resistor, V4 is the voltage corresponding to the fourth resistor, I4 is the current corresponding to the fourth resistor, delta4 is the zero drift parameter of the fourth resistor, and R_sen is the sensitivity drift parameter.

7. The method according to claim 1, characterized in that After obtaining the Wheatstone bridge model, the method further includes: Performing simulation based on the Wheatstone bridge model to obtain a simulated voltage-temperature curve; Based on the simulated voltage-temperature curve, the temperature drift characteristic of the Wheatstone bridge is verified.

8. A device for establishing a temperature drift Wheatstone bridge model, characterized in that: The device comprises: A data processing module is used to obtain the voltage data actually output by the Wheatstone bridge at different temperatures to obtain a measured voltage-temperature curve; A parameter calculation module, used to calculate the model parameters of the Wheatstone bridge model according to the voltage-temperature curve, wherein the model parameters include a sensitivity drift parameter and a zero drift parameter; The model building module is used to establish a model expression based on the sensitivity drift parameter and the zero drift parameter to obtain the Wheatstone bridge model.

9. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

Images