A core characteristic matching method for differential pressure measurement using a piezoresistive dual-core bridge.

Abstract

This invention relates to a method for matching the characteristics of piezoresistive dual-core bridge differential pressure measurement, comprising step 1: collecting the resistance R of the two bridge arms used for bridging of a batch of piezoresistive cores under the following conditions: low temperature and zero pressure, low temperature and full pressure, medium temperature and zero pressure, medium temperature and full pressure, high temperature and zero pressure, and high temperature and full pressure. a R b Step 1: Calculate the required supply voltage for each piezoresistive core half-bridge under medium temperature conditions, and calculate the theoretical supply voltage E of the differential bridge by averaging the values. Step 2: Select two piezoresistive cores in sequence and connect them to the differential bridge circuit model. Step 3: When the pressure on both half-bridges of the differential bridge is the reference pressure, adjust the compensation parameters of the differential bridge circuit model so that the zero-point output of the differential bridge meets the requirements. Step 4: Calculate the full-scale output of the two half-bridges of the differential bridge under low temperature, medium temperature, and high temperature conditions. Step 5: Calculate the difference between the full-scale output of the two half-bridges under low temperature, medium temperature, and high temperature conditions, and use this difference as the basis for core characteristic matching.

Description

Technical Field

[0001] This invention belongs to the field of silicon piezoresistive sensor technology and relates to a core characteristic matching method for piezoresistive dual-core bridge differential pressure measurement. Background Technology

[0002] In applications of differential pressure measurement based on the silicon piezoresistive principle, two common schemes exist. One involves using a single differential pressure core to simultaneously sense both the main pressure medium and the reference pressure, outputting a signal proportional to the differential pressure. The other uses two absolute pressure cores or gauge pressure cores to sense the main pressure medium and the reference pressure respectively, then subtracts the output signals from the two cores in the back-end circuit to output a signal proportional to the differential pressure. In dual-core differential pressure measurement applications, a differential bridge using partial force-sensitive resistors from both cores can be used to achieve a differential voltage output corresponding to the differential pressure, meeting the requirements of differential pressure measurement.

[0003] In a differential pressure measurement scheme using a dual-core differential bridge, when the differential pressure remains constant while the reference pressure changes, the voltage values ​​at the intermediate nodes of the two core half-bridges must change in the same direction and with equal amplitude as the reference pressure changes. This prevents measurement errors caused by variations in reference pressure. Conversely, mismatched characteristics between the two cores will result in differences in the magnitude of the voltage changes at the intermediate nodes of the two half-bridges as the reference pressure changes. This difference in voltage output will affect the accuracy of the differential pressure measurement. This output error caused by reference pressure changes can only be adjusted by changing the slope of the linear relationship between the voltage at the intermediate nodes of the main and reference half-bridges as a function of pressure. When the slopes of the linear relationships between the intermediate node potentials of the main and reference half-bridges are equal, the effects of the reference pressure increase or decrease on the intermediate node potentials of the main and reference half-bridges are in the same direction and with equal amplitude, thus canceling each other out. Therefore, the reference pressure has no effect on the differential pressure measurement.

[0004] To pre-match the characteristics of the two cores forming the differential bridge, it is necessary to analyze the characteristics of the cores to find a matching solution and reduce the impact of reference pressure on differential pressure measurement accuracy caused by characteristic mismatch between the two cores. Currently, many domestic sensor manufacturers use chip location marking to attempt to match characteristics by taking two chips from adjacent positions on the wafer. However, in practical engineering applications, characteristic mismatch between cores packaged from adjacent chips still occurs, leading to the problem of reference pressure affecting differential pressure measurement accuracy after the differential bridge is assembled. Summary of the Invention

[0005] The purpose of this invention is to provide a core characteristic matching method for piezoresistive dual-core bridge differential pressure measurement, which is used in differential bridge differential pressure measurement applications to eliminate the influence of reference pressure changes on the accuracy of differential pressure measurement. This invention can provide a feasible solution and approach for eliminating the influence of reference pressure in product design based on the differential bridge principle, improve the measurement accuracy of differential pressure sensors, and provide a feasible solution for characteristic matching of the key pressure sensing element of the product—the pressure core.

[0006] The technical solution of this invention is:

[0007] A method for matching the core characteristics of a piezoresistive dual-core bridge differential pressure measurement includes the following steps:

[0008] Step 1: Collect the resistance R of the two bridge arms used for bridging of the batch of piezoresistive cores under the following conditions: low temperature and zero pressure, low temperature and full pressure, medium temperature and zero pressure, medium temperature and full pressure, high temperature and zero pressure, and high temperature and full pressure. a R b Resistance value;

[0009] Step 2: Based on the full-scale output requirements of the differential bridge, calculate the required supply voltage for each piezoresistive core half-bridge under medium temperature conditions, and calculate the average theoretical supply voltage E of the differential bridge.

[0010] Step 3: Select two piezoresistive cores in sequence and connect them into the differential bridge circuit model;

[0011] Step 4: When the pressure on both halves of the differential bridge is the reference pressure, adjust the compensation parameters of the differential bridge circuit model so that the zero-point output of the differential bridge meets the requirements.

[0012] Step 5: Calculate the full-scale output of the two half-bridges of the differential bridge under low temperature, medium temperature, and high temperature conditions;

[0013] Step 6: Calculate the difference between the full-scale output of the two half-bridges under low temperature, medium temperature, and high temperature conditions, and use this difference as the basis for matching the core characteristics.

[0014] Furthermore, in step 2, the required supply voltage E for each piezoresistive core half-bridge is calculated using the following formula:

[0015]

[0016] In the formula, ΔV is the theoretical full-scale output value of the differential bridge; R a0 R b0 For the two bridge arm resistors R a R b Resistance value under zero-point pressure conditions; R am R bm For the two bridge arm resistors Ra R b Resistance value under full-point pressure conditions.

[0017] Furthermore, the differential bridge circuit model in step 3 includes: resistors R in the two half-bridges. a1 and R a2 Connected to the positive power supply terminal of the differential bridge; resistor R S R b1 and R b2 Connected; resistor R P One end is connected to the positive power supply of the differential bridge, and the other end is connected to switch K. P Connected to resistor R a1 and R b1 The intermediate node O+ or resistor R of the half-bridge a2 and R b2 The middle node O- of the half-bridge; switch K S For R S The connection node selection bit is used when the switch K is activated. S R b1 and R S When the intermediate node is connected to the ground, R S Series in R b2 Up; when via switch K S R b2 and R S When the intermediate node is connected to the ground, R S Series in R b1 Up; Switch K P For R P Connection node selection bit, when R P via switch K P Connected to resistor R a1 and R b1 When the middle node O+ of the half-bridge is formed, R P Parallel connection in R a1 Up; when R P via switch K P Connected to resistor R a2 and R b2 When the middle node O of the half-bridge is formed, R P Parallel connection in R a2 superior;

[0018] Wherein, resistance R a1 and R b1 Resistance R a2 and R b2 These form the two half-bridges of the differential bridge.

[0019] Furthermore, in step 4, the reference pressure is the pressure benchmark value of the pressure difference to be measured.

[0020] Furthermore, in step 4, the compensation parameters of the differential bridge circuit model are adjusted to ensure that the zero-point output of the differential bridge meets the requirements. This specifically includes the following steps:

[0021] Step 4.1 Under medium temperature conditions, resistor R S Set the resistance value to zero, and set the resistance R... P The resistance value is set to 5MΩ;

[0022] Step 4.2 Calculate the resistance R under intermediate temperature conditions. a1 and R b1 The voltage divider value O+ and the resistance R of the half-bridge are formed. a2 and R b2 Given the voltage divider value O- of the half-bridge, calculate the voltage difference between O+ and O-.

[0023] Step 4.3 Under medium temperature conditions, when the voltage difference between O+ and O- is greater than 0, switch K... S Grounding node and resistor R b1 and R S Connect the intermediate nodes to increase R. S The resistance value is such that the voltage difference between O+ and O- is 0; when the voltage difference between O+ and O- is less than 0, switch K... S Grounding node and resistor R b2 and R S Connect the intermediate nodes to increase R. S The resistance value is such that the voltage difference between O+ and O- is 0;

[0024] Step 4.4 Calculate the resistance R under low temperature and high temperature conditions respectively. a1 and R b1 The voltage divider value O+ and the resistance R of the half-bridge are formed. a2 and R b2 Given the voltage divider value O- of the half-bridge, calculate the voltage difference between O+ and O-.

[0025] Step 4.5 When the voltage difference between O+ and O- under low temperature conditions is greater than the voltage difference between O+ and O- under high temperature conditions, the resistance R P via switch K P Connecting to O+ reduces resistance R. P The resistance value is such that the voltage difference between O+ and O- at low temperatures is equal to the voltage difference between O+ and O- at high temperatures; when the voltage difference between O+ and O- at low temperatures is less than the voltage difference between O+ and O- at high temperatures, the resistance R... P via switch K P Connecting to O- reduces resistance R. P The resistance value is such that the voltage difference between O+ and O- under low temperature conditions is equal to the voltage difference between O+ and O- under high temperature conditions;

[0026] Step 4.6 Repeat steps 4.2 to 4.5 so that the voltage difference between O+ and O- is 0 under medium temperature conditions, and the voltage difference between O+ and O- under low temperature conditions is equal to the voltage difference between O+ and O- under high temperature conditions.

[0027] Furthermore, in step 5, the full-scale output requirement is measured by the change in output of any half-bridge when the pressure to be measured is at its minimum and maximum values.

[0028] Specifically, the following steps are included:

[0029] Step 5.1 Calculate the full-scale output of the two half-bridges of the differential bridge under low temperature conditions. That is, under low temperature conditions, the difference between the output voltage value of the intermediate node of any half-bridge when the measured pressure is at its maximum value and the output voltage value of the intermediate node of the same half-bridge when the measured pressure is at its minimum value. That is, the amount by which the O+ or O- output voltage value changes with pressure.

[0030] Step 5.2 Calculate the full-scale output of the two half-bridges of the differential bridge under medium temperature conditions, that is, the difference between the output voltage value of the intermediate node of any half-bridge when the measured pressure is at its maximum value and the output voltage value of the intermediate node of the same half-bridge when the measured pressure is at its minimum value under medium temperature conditions.

[0031] Step 5.3 Calculate the full-scale output of the two half-bridges of the differential bridge under high temperature conditions, that is, the difference between the output voltage value of the intermediate node of any half-bridge when the measured pressure is at its maximum value and the output voltage value of the intermediate node of the same half-bridge when the measured pressure is at its minimum value under high temperature conditions.

[0032] Furthermore, in step 6, the difference between the full-scale outputs of the two half-bridges under low temperature, medium temperature, and high temperature conditions is calculated, specifically including the following steps:

[0033] Step 6.1 Calculate the difference between the full-scale outputs of the two half-bridges of the differential bridge under low-temperature conditions;

[0034] Step 6.2 Calculate the difference in full-scale output between the two half-bridges of the differential bridge under medium temperature conditions;

[0035] Step 6.3 Calculate the difference in full-scale output between the two half-bridges of the differential bridge under high-temperature conditions.

[0036] Furthermore, when the difference between the full-scale outputs of the two half-bridges is lower than the required value under low temperature, medium temperature, and high temperature conditions, it indicates that the two piezoresistive cores can be used to form a differential bridge.

[0037] The advantages of this invention are:

[0038] This invention comprehensively analyzes the differential bridge by considering both the main pressure and reference half-bridges and the zero-point output compensation model. By selecting two core half-bridges with similar full-scale outputs after compensation for matching, the impact of reference pressure variations on differential pressure measurement accuracy is reduced. This invention effectively guides the characteristic matching of the two cores used in the differential bridge, eliminating the need for physical compensation and testing verification processes, significantly reducing core matching time and improving the characteristic matching success rate. Using this method for characteristic matching, the measurement error caused by the reference pressure influence on the differential bridge is compensated, improving the yield rate of differential pressure products based on the differential bridge principle.

[0039] In differential bridge pressure measurement applications, this invention takes the influence of reference pressure on the accuracy of differential pressure measurement as the evaluation object. By quantifying the relationship between the output signal of the intermediate node of the two pressure core half-bridges constituting the differential bridge and the pressure, it provides calculation formulas for the full-scale output characteristic indicators of the two core half-bridges under low, medium, and high temperature conditions. Characteristic matching is performed using these quantified indicators, meeting the needs of dual-core matching in actual production. The method utilizes batch calculation and automatic sorting matching analysis, achieving rapid and successful matching without the need for physical testing verification.

[0040] The table below compares the output results of the differential bridge circuit before and after using the present invention for characteristic matching. It can be seen that the method described in the present invention can assess the error introduced by the reference pressure in advance and perform targeted dual-core characteristic matching to reduce the impact of the reference pressure on the accuracy of differential pressure measurement.

[0041]

[0042] Attached Figure Description

[0043] Figure 1 It is a characteristic matching circuit for a dual-core half-bridge differential bridge;

[0044] Figure 2 The relationship between the full-scale output of the dual-core half-bridge and temperature;

[0045] In the diagram, 1-main pressure core half-bridge, 2-reference core half-bridge, R P R S - Resistance, K S K P -switch. Detailed Implementation

[0046] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0047] Please see Figure 1A differential bridge circuit model for a piezoresistive dual-core bridge differential voltage measurement core characteristic matching method includes: resistors R in the two half-bridges. a1 and R a2 Connected to the positive power supply terminal of the differential bridge; resistor R S R b1 and R b2 Connected; resistor R P One end is connected to the positive power supply of the differential bridge, and the other end is connected to switch K. P Connected to resistor R a1 and R b1 The intermediate node O+ or resistor R of the half-bridge a2 and R b2 The middle node O- of the half-bridge; switch K S For R S The connection node selection bit is used when the switch K is activated. S R b1 and R S When the intermediate node is connected to the ground, R S Series in R b2 Up; when via switch K S R b2 and R S When the intermediate node is connected to the ground, R S Series in R b1 Up; Switch K P For R P Connection node selection bit, when R P via switch K P Connected to resistor R a1 and R b1 When the middle node O+ of the half-bridge is formed, R P Parallel connection in R a1 Up; when R P via switch K P Connected to resistor R a2 and R b2 When the middle node O of the half-bridge is formed, R P Parallel connection in R a2 Above; where the resistance R a1 and R b1 Resistance R a2 and R b2 These form the two half-bridges of the differential bridge.

[0048] The following example, using two piezoresistive cores, illustrates the process of characteristic matching between dual cores:

[0049] First, the resistance R of the two bridge arms used for bridging was collected under the following conditions: low temperature and zero pressure, low temperature and full pressure, medium temperature and zero pressure, medium temperature and full pressure, high temperature and zero pressure, and high temperature and full pressure. a R b Resistance value.

[0050]

[0051]

[0052] Based on the full-scale output requirement of the differential bridge, the required supply voltage for each piezoresistive half-bridge is calculated under medium-temperature conditions, and the theoretical supply voltage E of the differential bridge is obtained by averaging. If the full-scale output requirement of the differential bridge is ΔV, then the required supply voltages for the two half-bridges under medium-temperature conditions are as follows:

[0053]

[0054]

[0055] Calculate the average value of E1 and E2 to obtain the theoretical supply voltage E of the core half-bridge.

[0056] Please see Figure 1 , resistor R S The resistance value is set to zero, and the resistance R P The resistance value is set to 5MΩ, the zero-point pressure is P0, and the full-point pressure is P. m At a reference pressure of P, under intermediate temperature conditions, the arm resistance R of the two core half-bridges is... a R b The resistance values ​​are as follows:

[0057]

[0058] At this point, with voltage E applied to the half-bridges of cores 1 and 2 respectively, the voltage division value V between the two half-bridges can be calculated. O+M and V O-M And calculate its voltage difference ΔV OM .

[0059] V O+M =E·R brM01 / (R arM01 +R brM01 )

[0060] V O-M =E·R brM02 / (R arM02 +R brM02 )

[0061] ΔVOM =(V O+M -V O-M )

[0062] When ΔV OM When greater than 0, switch K S Grounding node and resistor R b1 and R S Connect the intermediate nodes to increase R. S The resistance value makes ΔV OM =0; when ΔV OM When less than 0, switch K S Grounding node and resistor R b2 and R S Connect the intermediate nodes to increase R. S The resistance value makes ΔV OM It is 0.

[0063] Using the same method as above, calculate the voltage difference ΔV between O+ and O- under low and high temperature conditions. OL and ΔV OH ;

[0064] When ΔV OL Greater than ΔV OH When, resistance R P via switch K P Connecting to O+ reduces resistance R. P The resistance value makes ΔV OL With ΔV OH Equal; when ΔV OL Less than ΔV OH When, resistance R P via switch K P Connecting to O- reduces resistance R. P The resistance value makes ΔV OL With ΔV OH equal.

[0065] After the above adjustments, the resistance R can be obtained. S and resistance R P The resistance value, and switch K S and switch K P The short-circuit method has been determined, and the next calculation is carried out based on this. For two different core half-bridges, the calculated resistance R is... S and resistance R P Switch K S and switch K P They are all different; here we assume that the resistance R of the two core half-bridge arms is different. a and R b In series resistance R S and parallel resistor R P The resistance values ​​become as shown in the table below:

[0066]

[0067] Calculate the full-scale output V of the two half-bridges of the differential bridge under low-temperature conditions. FSL1 and V FSL2 :

[0068] V FSL1 =E·(R) ’ bLm1 / (R ’ aLm1 +R ’ bLm1 )-R ’ bL01 / (R ’ aL01 +R ’ bL01 ))

[0069] V FSL2 =E·(R) ’ bLm2 / (R ’ aLm2 +R ’ bLm2 )-R ’ bL02 / (R ’ aL02 +R ’ bL02 ))

[0070] Calculate the full-scale output V of the two half-bridges of the differential bridge under intermediate temperature conditions. FSM1 and V FSM2 :

[0071] V FSM1 =E·(R) ’ bMm1 / (R ’ aMm1 +R ’ bMm1 )-R ’ bM01 / (R ’ aM01 +R ’ bM01 ))

[0072] V FSM2 =E·(R) ’ bMm2 / (R ’ aMm2 +R ’ bMm2 )-R ’ bM02 / (R’ aM02 +R ’ bM02 ))

[0073] Calculate the full-scale output V of the two half-bridges of the differential bridge under high temperature conditions. FSH1 and V FSH2 :

[0074] V FSH1 =E·(R) ’ bHm1 / (R ’ aHm1 +R ’ bHm1 )-R ’ bH01 / (R ’ aH01 +R ’ bH01 ))

[0075] V FSH2 =E·(R) ’ bHm2 / (R ’ aHm2 +R ’ bHm2 )-R ’ bH02 / (R ’ aH02 +R ’ bH02 ))

[0076] Calculate the difference between the full-scale outputs of the two half-bridges under low temperature, medium temperature, and high temperature conditions respectively:

[0077] ΔV FSL =V FSL1 -V FSL2

[0078] ΔV FSM =V FSM1 -V FSM2

[0079] ΔV FSH =V FSH1 -V FSH2

[0080] Please see Figure 2 By plotting the full-scale output difference of each core half-bridge against temperature characteristics, comparing the closeness of the curves, and selecting two core half-bridges with similar differences at all temperature points for matching, the influence of reference pressure on the differential bridge pressure measurement accuracy can be weakened or even eliminated, thereby improving the production yield.

Claims

1. A method for matching the core characteristics of a piezoresistive dual-core bridge differential pressure measurement, characterized in that, Includes the following steps: Step 1: Collect the resistance R of the two bridge arms used for bridging of the batch of piezoresistive cores under the following conditions: low temperature and zero pressure, low temperature and full pressure, medium temperature and zero pressure, medium temperature and full pressure, high temperature and zero pressure, and high temperature and full pressure. a R b Resistance value; Step 2: Based on the full-scale output requirements of the differential bridge, calculate the required supply voltage for each piezoresistive core half-bridge under medium temperature conditions, and calculate the average theoretical supply voltage E of the differential bridge. Step 3: Select two piezoresistive cores in sequence and connect them into the differential bridge circuit model; Step 4: When the pressure on both halves of the differential bridge is the reference pressure, adjust the compensation parameters of the differential bridge circuit model so that the zero-point output of the differential bridge meets the requirements. Step 5: Calculate the full-scale output of the two half-bridges of the differential bridge under low temperature, medium temperature, and high temperature conditions; Step 6: Calculate the difference between the full-scale output of the two half-bridges under low temperature, medium temperature, and high temperature conditions, and use this difference as the basis for matching the core characteristics.

2. The core characteristic matching method for differential pressure measurement using a piezoresistive dual-core bridge as described in claim 1, characterized in that, In step 2, the required supply voltage E for each piezoresistive core half-bridge is calculated using the following formula: In the formula, ΔV is the theoretical full-scale output value of the differential bridge; R a0 R b0 For the two bridge arm resistors R a R b Resistance value under zero-point pressure conditions; R am R bm For the two bridge arm resistors R a R b Resistance value under full-point pressure conditions.

3. The core characteristic matching method for differential pressure measurement using a piezoresistive dual-core bridge as described in claim 2, characterized in that, The differential bridge circuit model in step 3 includes: resistors R in the two half-bridges. a1 and R a2 Connected to the positive power supply terminal of the differential bridge; resistor R S R b1 and R b2 Connected; resistor R P One end is connected to the positive power supply of the differential bridge, and the other end is connected to switch K. P Connected to resistor R a1 and R b1 The intermediate node O+ or resistor R of the half-bridge a2 and R b2 The middle node O- of the half-bridge; switch K S For R S The connection node selection bit is selected when the switch K is used. S R b1 and R S When the intermediate node is connected to the ground, R S Series in R b2 Up; when via switch K S R b2 and R S When the intermediate node is connected to the ground, R S Series in R b1 Up; Switch K P For R P Connection node selection bit, when R P via switch K P Connected to resistor R a1 and R b1 When the middle node O+ of the half-bridge is formed, R P Parallel connection in R a1 Up; when R P via switch K P Connected to resistor R a2 and R b2 When the middle node O of the half-bridge is formed, R P Parallel connection in R a2 superior; Wherein, resistance R a1 and R b1 Resistance R a2 and R b2 These form the two half-bridges of the differential bridge.

4. The core characteristic matching method for differential pressure measurement of a piezoresistive dual-core bridge according to claim 3, characterized in that, In step 4, the reference pressure is the pressure benchmark value of the pressure difference to be measured.

5. The core characteristic matching method for differential pressure measurement using a piezoresistive dual-core bridge as described in claim 4, characterized in that, In step 4, the compensation parameters of the differential bridge circuit model are adjusted to ensure that the zero-point output of the differential bridge meets the requirements. This specifically includes the following steps: Step 4.1 Under medium temperature conditions, resistor R S Set the resistance value to zero, and set the resistance R... P The resistance value is set to 5MΩ; Step 4.2 Calculate the resistance R under intermediate temperature conditions. a1 and R b1 The voltage divider value O+ and the resistance R of the half-bridge are formed. a2 and R b2 Given the voltage divider value O- of the half-bridge, calculate the voltage difference between O+ and O-. Step 4.3 Under medium temperature conditions, when the voltage difference between O+ and O- is greater than 0, switch K... S Grounding node and resistor R b1 and R S Connect the intermediate nodes to increase R. S The resistance value is such that the voltage difference between O+ and O- is 0; when the voltage difference between O+ and O- is less than 0, switch K... S Grounding node and resistor R b2 and R S Connect the intermediate nodes to increase R. S The resistance value is such that the voltage difference between O+ and O- is 0; Step 4.4 Calculate the resistance R under low temperature and high temperature conditions respectively. a1 and R b1 The voltage divider value O+ and the resistance R of the half-bridge are formed. a2 and R b2 Given the voltage divider value O- of the half-bridge, calculate the voltage difference between O+ and O-. Step 4.5 When the voltage difference between O+ and O- under low temperature conditions is greater than the voltage difference between O+ and O- under high temperature conditions, the resistance R P via switch K P Connecting to O+ reduces resistance R. P The resistance value is such that the voltage difference between O+ and O- at low temperatures is equal to the voltage difference between O+ and O- at high temperatures; when the voltage difference between O+ and O- at low temperatures is less than the voltage difference between O+ and O- at high temperatures, the resistance R... P via switch K P Connecting to O- reduces resistance R. P The resistance value is such that the voltage difference between O+ and O- under low temperature conditions is equal to the voltage difference between O+ and O- under high temperature conditions; Step 4.6 Repeat steps 4.2 to 4.5 so that the voltage difference between O+ and O- is 0 under medium temperature conditions, and the voltage difference between O+ and O- under low temperature conditions is equal to the voltage difference between O+ and O- under high temperature conditions.

6. The core characteristic matching method for differential pressure measurement using a piezoresistive dual-core bridge as described in claim 5, characterized in that, In step 5, the full-scale output requirement is measured by the change in output of any half-bridge when the pressure to be measured is at its minimum and maximum values. Specifically, the following steps are included: Step 5.1 Calculate the full-scale output of the two half-bridges of the differential bridge under low temperature conditions. That is, under low temperature conditions, the difference between the output voltage value of the intermediate node of any half-bridge when the measured pressure is at its maximum value and the output voltage value of the intermediate node of the same half-bridge when the measured pressure is at its minimum value. That is, the amount by which the O+ or O- output voltage value changes with pressure. Step 5.2 Calculate the full-scale output of the two half-bridges of the differential bridge under medium temperature conditions, that is, the difference between the output voltage value of the intermediate node of any half-bridge when the measured pressure is at its maximum value and the output voltage value of the intermediate node of the same half-bridge when the measured pressure is at its minimum value under medium temperature conditions. Step 5.3 Calculate the full-scale output of the two half-bridges of the differential bridge under high temperature conditions, that is, the difference between the output voltage value of the intermediate node of any half-bridge when the measured pressure is at its maximum value and the output voltage value of the intermediate node of the same half-bridge when the measured pressure is at its minimum value under high temperature conditions.

7. The core characteristic matching method for differential pressure measurement using a piezoresistive dual-core bridge as described in claim 6, characterized in that, Step 6 involves calculating the difference between the full-scale outputs of the two half-bridges under low, medium, and high temperature conditions. This includes the following steps: Step 6.1 Calculate the difference between the full-scale outputs of the two half-bridges of the differential bridge under low-temperature conditions; Step 6.2 Calculate the difference in full-scale output between the two half-bridges of the differential bridge under medium temperature conditions; Step 6.3 Calculate the difference in full-scale output between the two half-bridges of the differential bridge under high-temperature conditions.

8. The core characteristic matching method for differential pressure measurement using a piezoresistive dual-core bridge as described in claim 7, characterized in that, When the difference between the full-scale outputs of the two half-bridges is lower than the required value under low temperature, medium temperature, and high temperature conditions, it indicates that the two piezoresistive cores can be used to form a differential bridge.

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