Pressure sensor with pre-compensation

Abstract

This utility model relates to the field of pressure sensors, specifically to a pressure sensor with pre-compensation. The pre-compensated pressure sensor includes a sensor signal conditioning chip, a resistance bridge sensor, and a strain gauge. The resistance bridge sensor is disposed on the strain gauge and connected in conjunction with the sensor signal conditioning chip. The positive and / or negative terminals of the excitation source of the resistance bridge sensor are connected to the sensor signal conditioning chip via a temperature resistor with a positive temperature coefficient. This utility model improves measurement accuracy through pre-compensation using a temperature resistor.

Description

Technical Field

[0001] This utility model relates to the field of pressure sensors, specifically to a pressure sensor with pre-compensation. Background Technology

[0002] Current automotive pressure or force sensor circuits on the market consist of a sensor signal conditioning chip and a resistive bridge sensor connected in tandem. Calibration methods are based on automated chip calibration, supporting digital compensation for bias, gain, and nonlinearity. Calibration parameters are programmed via a single-wire interface, simplifying the calibration process. A key technical feature is modular design, such as the NMC3000 system from Nanochip Microelectronics, and the 4151 and 4169 from Renesas.

[0003] Automotive pressure sensors or force sensors rely on automated chip calibration (generally supporting pressure compensation at two or three temperature points) to achieve an accuracy of around ±2.5%. However, as the pressure or force range increases, the accuracy decreases. In particular, the most advanced chips currently available, such as Renesas, can only support up to eight pressure points for compensation in three temperature zones (normal temperature, high temperature, and low temperature). Typically, four points are written to one temperature zone, while the other two can only be compensated at two points. The two-point compensation uses the least squares method, which has the lowest accuracy.

[0004] The market is increasingly favoring intelligent driving in automobiles, which in turn demands higher accuracy from sensors. However, existing automotive pressure or force sensors, relying solely on automated chip calibration, cannot meet the accuracy requirements across the entire temperature range and measurement scale. Summary of the Invention

[0005] The technical problem to be solved by this utility model is to overcome the defects of the prior art and provide a pressure sensor with pre-compensation, which improves the measurement accuracy by pre-compensating through temperature resistance.

[0006] To solve the above-mentioned technical problems, the technical solution of this utility model is as follows: a pressure sensor with pre-compensation, comprising a sensor signal conditioning chip, a resistance bridge sensor, and a strain gauge, wherein the resistance bridge sensor is disposed on the strain gauge and is connected in cooperation with the sensor signal conditioning chip; wherein...

[0007] The positive and / or negative excitation source terminals of the resistive bridge sensor are connected to the sensor signal conditioning chip via a temperature resistor with a positive temperature coefficient.

[0008] Furthermore, the sensor signal conditioning chip is model ZSSC4169, ZSSC4151, or NMC3000 from Nanochip Microelectronics.

[0009] Furthermore, the temperature resistance is a pt resistor.

[0010] Furthermore, in order to improve measurement accuracy and precision through averaging, the resistive bridge sensor is configured with at least two connected in parallel, all of which are located on the strain gauge.

[0011] Furthermore, in order to pre-compensate each resistive bridge sensor separately, no two resistive bridge sensors share a temperature resistor.

[0012] Furthermore, the strain gauge is made of metal or silicon.

[0013] By adopting the above technical solution, this utility model can perform temperature compensation before the automatic calibration of the chip by adding a temperature resistor with a positive temperature coefficient in the sensor circuit design, which can greatly improve the accuracy of automotive pressure or force sensors and meet the usage requirements. Attached Figure Description

[0014] Figure 1 This is a circuit diagram of the pressure sensor with pre-compensation according to this utility model;

[0015] Figure 2 This is a schematic diagram showing the full-range measurement accuracy of a traditional pressure sensor circuit at various temperature points.

[0016] Figure 3 This is a schematic diagram showing the full-range measurement accuracy of the pressure sensor with pre-compensation of this utility model at various temperature points.

[0017] In the diagram, 1 is the sensor signal conditioning chip; 2 is the bridge resistive sensor; 3 is the strain gauge; and 4 is the temperature resistor. Detailed Implementation

[0018] To make the contents of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0019] like Figure 1 As shown, a pressure sensor with pre-compensation includes a sensor signal conditioning chip 1, a resistance bridge sensor 2, and a strain gauge 3. The resistance bridge sensor 2 is disposed on the strain gauge 3 and is connected in conjunction with the sensor signal conditioning chip 1; wherein,

[0020] The positive and / or negative excitation source terminals of the resistive bridge sensor 2 are connected to the sensor signal conditioning chip 1 through a temperature resistor 4 with a positive temperature coefficient.

[0021] Among them, strain gauge 3 is made of metal or silicon.

[0022] Specifically, considering that strain gauge 3 softens as ambient temperature rises, its elastic modulus decreases. This decrease in elastic modulus results in greater deformation under the same external force, leading to increased output of the resistive bridge sensor 2. In other words, rising ambient temperature causes a traditional pressure sensor to output more power under the same external force and excitation voltage. Therefore, this embodiment uses a temperature-sensitive resistor 4 with a positive temperature coefficient as a compensation resistor, connected to the input circuit of the resistive bridge sensor 2. As temperature rises, the resistance of the temperature-sensitive resistor 4 increases, increasing the voltage drop across the bridge current. Since the applied excitation voltage V is stable, the actual excitation voltage applied to the resistive bridge sensor 2 decreases, preventing the actual output of the sensor circuit from increasing with temperature. This achieves our compensation objective and significantly improves the accuracy of automotive pressure or force sensors.

[0023] In this embodiment, the sensor signal conditioning chip 1 can be a ZSSC4169 or ZSSC4151 or a Nanochip NMC3000 or other mainstream chips.

[0024] In this embodiment, preferably, the temperature resistance 4 is a pt resistor.

[0025] In this embodiment, as Figure 1 As shown, preferably, the resistance bridge sensor 2 is configured with at least two connected in parallel, all of which are disposed on the strain gauge 3. In this way, the measurement accuracy and precision can be improved by averaging.

[0026] More preferably, the temperature resistor 4 is not shared between any two resistance bridge sensors 2. In this way, pre-compensation can be performed on each resistance bridge sensor separately, further improving measurement accuracy and precision.

[0027] The following section uses the ZSSC4151 chip as the sensor signal conditioning chip 1 as an example, and combines specific embodiments and comparative examples to introduce in detail the advantages of the pressure sensor involved in the above embodiments.

[0028] Example 1: A pressure sensor with pre-compensation, such as Figure 1 As shown, the VDDE pin of the ZSSC4151 chip is connected to the external power supply VCC, the VSSE pin is connected to GND, the BRIP pin is connected to the pt resistor and then to the positive terminal of the excitation source of the resistor bridge sensor 2, the BRIN pin is connected to the negative terminal of the excitation source of the resistor bridge sensor 2, the TOP pin is connected to the positive terminal of the output of the resistor bridge sensor 2, and the BOT pin is connected to the negative terminal of the output of the resistor bridge sensor 2.

[0029] Among them, there are two parallel resistor bridge sensors 2, both located on the strain gauge 3, and each is equipped with a temperature resistor 4 with a positive temperature coefficient. The temperature resistor 4 is connected between the BRIP pin of the ZSSC4151 chip and the positive terminal of the excitation source of the corresponding resistor bridge sensor 2.

[0030] This embodiment achieves temperature pre-compensation by adding a temperature resistor 4 to the sensor circuit design. After completing the automated calibration of the chip, the full-range measurement accuracy at each temperature point is as follows: Figure 3 As shown.

[0031] Comparative Example 1: A pressure sensor, differing from Example 1 in that it does not include a temperature resistor 4. After automated chip calibration, the full-range measurement accuracy at various temperature points is as follows: Figure 2 As shown.

[0032] By comparing the accuracy of Example 1 and Comparative Example 1, it is clear that the pressure sensor in Example 1 has significantly better measurement accuracy across the entire measurement range than that in Comparative Example 1.

[0033] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A pressure sensor with pre-compensation, characterized in that, it comprises a sensor signal conditioning chip (1), a resistance bridge sensor (2) and a strain gauge (3), the resistance bridge sensor (2) is arranged on the strain gauge (3) and is connected with the sensor signal conditioning chip (1) in cooperation; wherein, the positive pole and / or the negative pole of the excitation source of the resistance bridge sensor (2) is connected with the sensor signal conditioning chip (1) through a temperature resistance (4) with positive temperature coefficient.

2. The pressure sensor with pre-compensation according to claim 1, characterized in that, the model of the sensor signal conditioning chip (1) is ZSSC4169 or ZSSC4151 or NMC3000 of Nanxinwei.

3. The pressure sensor with pre-compensation according to claim 1, characterized in that, the temperature resistance (4) is a pt resistance.

4. The pressure sensor with pre-compensation according to claim 1, characterized in that, the resistance bridge sensor (2) is configured with at least two in parallel, and each is arranged on the strain gauge (3).

5. The pressure sensor with pre-compensation according to claim 4, characterized in that, any two resistance bridge sensors (2) do not share a temperature resistance (4).

6. The pressure sensor with pre-compensation according to claim 1, characterized in that, the material of the strain gauge (3) is metal or silicon-based.

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