Pressure sensor circuit with built-in MCU
By using ceramic capacitors and micro-current sensor circuits, the problem of low accuracy of pressure sensors under high and low temperature environments was solved. Second-order temperature drift calibration of zero point and sensitivity of pressure sensors in the thermal management system of new energy vehicles was achieved, thus solving the problem of low sensor accuracy in the thermal management system of new energy vehicles.
Patent Information
- Application Number
- CN202423235475.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-26
- Publication Date
- 2025-12-19
- Estimated Expiration
- 2034-12-26
AI Technical Summary
In high and low temperature environments, pressure sensors in the thermal management system of new energy vehicles suffer from low accuracy and data drift.
The pressure sensor circuit employs ceramic capacitors and micro-currents. The zero point and sensitivity of the pressure sensor are calibrated by second-order temperature drift through the main chip, with a calibration accuracy of less than 0.1%. The calibration coefficients are stored in a set of reprogrammable EEPROMs.
The zero point and sensitivity of the pressure sensor were calibrated to achieve second-order temperature drift, with a calibration accuracy of less than 0.1%. This solved the problems of low accuracy of pressure sensors and data drift in high and low temperature environments in the thermal management system of new energy vehicles.
Smart Images
Figure CN223691913U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to pressure sensor field, concretely is a pressure sensor circuit of built -in MCU. BACKGROUND
[0002] Temperature change under high and low temperature environment can influence the physical property of sensor internal material, and then causes mechanical deformation and electric characteristic change, these changes can cause sensor output value to have the offset, namely so -called "drift" phenomenon, make new energy automobile heat management system technology, there is the precision of pressure sensor under high and low temperature environment is not high and output data drift problem, need to improve. CONTENT OF UTILITY MODEL
[0003] The utility model discloses a pressure sensor circuit of built -in MCU to solve the problem in the background art.
[0004] To achieve the above object, the utility model provides the following technical scheme:
[0005] A pressure sensor circuit of built -in MCU, it includes:
[0006] Ceramic capacitor is used to change the electric capacity when pressure changes, and feedback electric capacity signal to main chip;
[0007] Main chip is used to output 0-5V voltage based on the size of input electric capacity signal;
[0008] Ceramic capacitor connects main chip.
[0009] As the further scheme of the utility model: main chip includes chip U1, the model of chip U1 is NSC9260, and the 5, 7 pin of chip U1 connects the first end, third end of ceramic capacitor, and the second end of ceramic capacitor is grounded.
[0010] As the further scheme of the utility model: the pressure sensor circuit of built -in MCU still includes power supply anti -interference element, and the power supply anti -interference element includes protection tube D1, capacitor C1, capacitor C2, one end of capacitor C1 connects the first end of protection tube D1, voltage VCC, and the other end of capacitor C1 connects metal shell, and metal shell is grounded through capacitor C2, and the second end of protection tube D1 is grounded.
[0011] As a further scheme of the utility model: the pressure sensor circuit with built-in MCU further includes a power supply filtering element, the power supply filtering element includes inductance BD1, resistance R3, capacitor C3, capacitor C8, capacitor C10, one end of inductance BD1 is connected with voltage VCC, the other end of inductance BD1 is connected with one end of capacitor C3, one end of resistance R3, the other end of capacitor C3 is grounded, the other end of resistance R3 is connected with one end of capacitor C10, one end of capacitor C8, the 16th pin of chip U1, the other end of capacitor C8 is grounded, and the other end of capacitor C10 is grounded.
[0012] As a further scheme of the utility model: the pressure sensor circuit with built-in MCU further includes an output anti-interference element, the output anti-interference element includes capacitor C7, capacitor C9, inductance BD2 and protection tube D2, one end of inductance BD2 is connected with one end of capacitor C7, one end of capacitor C9, one end of resistance R1 and one end of resistance R2, the other end of capacitor C7 is grounded, the other end of capacitor C9 is grounded, the other end of resistance R1 is connected with the 13th and 14th pins of chip U1, the other end of resistance R2 is connected with the 12th pin of chip U1, the other end of inductance BD2 is connected with the first end of protection tube BD2, and the second end of protection tube BD2 is grounded.
[0013] Compared with the prior art, the utility model has the advantages that the utility model calibrates the zero point, the sensitivity and the second-order temperature drift (the highest third-order nonlinearity) of the pressure sensor through the main chip, the calibration precision can reach within 0.1%, the calibration coefficient is stored in a set of multiple programmable EEPROM, and the problems of low precision of the pressure sensor, output data drift under high and low temperature environments and the like in the new energy automobile thermal management system technology are solved. BRIEF DESCRIPTION OF DRAWINGS
[0014] Figure 1 It is a circuit diagram of the pressure sensor circuit with built-in MCU.
[0015] Figure 2 It is a main chip signal diagram. DETAILED DESCRIPTION
[0016] The technical scheme in the embodiments of the utility model will be clearly and completely described in combination with the drawings in the embodiments of the utility model, and apparently, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments, and all other embodiments obtained by those skilled in the art without creative labor on the basis of the embodiments in the utility model belong to the protection scope of the utility model.
[0017] Please refer to Figure 1 A pressure sensor circuit with built-in MCU, comprising:
[0018] ceramic capacitor, for changing capacitance when pressure changes, feeding back capacitance signal to main chip;
[0019] main chip, for outputting 0-5V voltage based on size of input capacitance signal;
[0020] ceramic capacitor connects main chip.
[0021] In the embodiment, refer to Figure 1 , the main chip comprises chip U1, the model of chip U1 is NSC9260, the 5th pin and the 7th pin of chip U1 are connected with the first end and the third end of the ceramic capacitor, and the second end of the ceramic capacitor is grounded.
[0022] The sensitive element ceramic capacitor adopts ceramic diaphragm, and the ceramic diaphragm and the ceramic base are used as two polar plates of the capacitor. When the pressure changes, the ceramic diaphragm deforms and displaces, and the gap between the ceramic diaphragm and the ceramic base changes. The deformation displacement causes the capacitance of the ceramic capacitor to change slightly. Chip U1 detects the slight capacitance change of the ceramic capacitor, amplifies and converts it through chip U1, and then processes it through the internal MCU nonlinear correction and temperature compensation algorithm to output a 0-5V pressure value voltage.
[0023] Amplification conversion, nonlinear correction and temperature compensation are common technologies of chip U1. Chip U1 (NSC9260) is a high-integration signal conditioning special chip for capacitive sensors that meets the AEC-Q100 standard. It supports overvoltage and reverse voltage protection functions, supports analog voltage output, PWM output multiple output modes, and supports sensor diagnosis functions.
[0024] Refer to Figure 2 , the sensor output signal is amplified through the main signal channel and quantized to 24-bit digital output by PADC, and the temperature signal is amplified by the auxiliary temperature measurement channel and quantized to 24-bit temperature digital output by TADC. After the two digital signals are calibrated by the zero point and sensitivity of the built-in MCU, the second-order temperature drift calibration algorithm, the percentage value of the target value of the sensor is output, which is converted into the voltage output corresponding to the percentage value by DAC. Calibration can be divided into ADC calibration (ADC_CAL), sensor calibration (SENSOR_CAL), range ratio adjustment and DAC calibration (DAC_CAL). The ADC calibration part is used to calibrate the zero point and sensitivity of the PADC output in the analog input module and the zero point and sensitivity of the TADC output temperature data. The sensor calibration part is used to adjust the zero point, sensitivity, nonlinearity, and temperature drift of the zero point and sensitivity of the sensor. The range ratio adjustment part can conveniently modify the range of the product after the module calibration is completed. The DAC calibration part is used to calibrate the zero point and sensitivity deviation of the analog output module.
[0025] In order to unify the data format and unit in the calibration calculation process, the PADC and TADC outputs, the DAC input and the like are normalized. The normalized value is the ratio of the current physical quantity to the corresponding full scale, that is, the percentage of the output relative to the full scale.
[0026] In the embodiment, please refer to Figure 1 The pressure sensor circuit with the built-in MCU further comprises a power anti-interference element, the power anti-interference element comprises a protection tube D1, a capacitor C1 and a capacitor C2, one end of the capacitor C1 is connected to the first end of the protection tube D1 and a voltage VCC, the other end of the capacitor C1 is connected to a metal shell, the metal shell is grounded through the capacitor C2, and the second end of the protection tube D1 is grounded.
[0027] The voltage VCC is used as the power supply of the chip U1. In order to avoid the interference to the voltage VCC, the power anti-interference element is arranged. When the interference voltage is too large, the protection tube D1 is turned on to be grounded to discharge the voltage, and the metal shell is connected between the capacitors C1 and C2 to be grounded, so that the electromagnetic interference is reduced.
[0028] In the embodiment, please refer to Figure 1 The pressure sensor circuit with the built-in MCU further comprises a power supply filtering element, the power supply filtering element comprises an inductor BD1, a resistor R3, a capacitor C3, a capacitor C8 and a capacitor C10, one end of the inductor BD1 is connected to the voltage VCC, the other end of the inductor BD1 is connected to one end of the capacitor C3 and one end of the resistor R3, the other end of the capacitor C3 is grounded, the other end of the resistor R3 is connected to one end of the capacitor C10, one end of the capacitor C8 and the 16th pin of the chip U1, the other end of the capacitor C8 is grounded, and the other end of the capacitor C10 is grounded.
[0029] The voltage VCC is filtered by the power supply filtering element to ensure that the voltage output to the chip U1 is stable.
[0030] In the embodiment, please refer to Figure 1 The pressure sensor circuit with the built-in MCU further comprises an output anti-interference element, the output anti-interference element comprises a capacitor C7, a capacitor C9, an inductor BD2 and a protection tube D2, one end of the inductor BD2 is connected to one end of the capacitor C7, one end of the capacitor C9, one end of the resistor R1 and one end of the resistor R2, the other end of the capacitor C7 is grounded, the other end of the capacitor C9 is grounded, the other end of the resistor R1 is connected to the 13th and 14th pins of the chip U1, the other end of the resistor R2 is connected to the 12th pin of the chip U1, the other end of the inductor BD2 is connected to the first end of the protection tube BD2, and the second end of the protection tube BD2 is grounded.
[0031] The 0-5V voltage (reacting current pressure value) output by the chip U1 is output through an output anti-interference element, the oscillation of the capacitor C7 and C9 is smoothed, high frequency noise is filtered, the inductor BD2 blocks high frequency and low frequency and suppresses electromagnetic interference.
[0032] The working principle of the utility model is: the ceramic capacitor is used for changing the capacitance when the pressure changes, and feeding back the capacitance signal to the main chip; the main chip is used for outputting 0-5V voltage based on the size of the input capacitance signal.
[0033] For those skilled in the art, it is obvious that the utility model is not limited to the details of the above-mentioned exemplary embodiments, and the utility model can be realized in other specific forms without departing from the spirit or basic characteristics of the utility model.
[0034] In addition, it should be understood that, although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that those skilled in the art can understand.
Claims
1. An MCU-in-pixel pressure sensor circuit, characterized by, The pressure sensor circuit with built-in MCU comprises: a ceramic capacitor for changing the capacitance when the pressure changes and feeding back the capacitance signal to the main chip; a main chip for outputting 0-5V voltage based on the size of the input capacitance signal; the ceramic capacitor is connected to the main chip.
2. The pressure sensor circuit with built-in MCU according to claim 1, wherein, The main chip comprises chip U1, the model of which is NSC9260, the 5th and 7th pins of which are connected to the first and third ends of the ceramic capacitor, and the second end of the ceramic capacitor is grounded.
3. The pressure sensor circuit with built-in MCU according to claim 2, wherein, The pressure sensor circuit with built-in MCU further comprises a power anti-interference element, which comprises protection tube D1, capacitor C1 and capacitor C2, one end of capacitor C1 is connected to the first end of protection tube D1 and voltage VCC, the other end of capacitor C1 is connected to the metal shell, the metal shell is grounded through capacitor C2, and the second end of protection tube D1 is grounded.
4. The pressure sensor circuit with built-in MCU according to claim 2, wherein, The pressure sensor circuit with built-in MCU further comprises a power filtering element, which comprises inductor BD1, resistor R3, capacitor C3, capacitor C8 and capacitor C10, one end of inductor BD1 is connected to voltage VCC, the other end of inductor BD1 is connected to one end of capacitor C3 and one end of resistor R3, the other end of capacitor C3 is grounded, the other end of resistor R3 is connected to one end of capacitor C10, one end of capacitor C8 and the 16th pin of chip U1, the other end of capacitor C8 is grounded, and the other end of capacitor C10 is grounded.
5. The MCU-in-pixel pressure sensor circuit of claim 2, wherein, The pressure sensor circuit with built-in MCU further comprises an output anti-interference element, which comprises capacitor C7, capacitor C9, inductor BD2 and protection tube D2, one end of inductor BD2 is connected to one end of capacitor C7, one end of capacitor C9, one end of resistor R1 and one end of resistor R2, the other end of capacitor C7 is grounded, the other end of capacitor C9 is grounded, the other end of resistor R1 is connected to the 13th and 14th pins of chip U1, the other end of resistor R2 is connected to the 12th pin of chip U1, the other end of inductor BD2 is connected to the first end of protection tube BD2, and the second end of protection tube BD2 is grounded.