Pressure sensor and method for fault localization thereof

Abstract

The application provides a pressure sensor and a fault positioning method thereof. The pressure sensor comprises a pressure sensor unit, a signal conditioning module, a digital-to-analog converter and an analog-to-digital converter. An analog sensing voltage signal output by the pressure sensor unit is converted into a sensing voltage value by the analog-to-digital converter, the signal conditioning module compensates and corrects the sensing voltage value based on the range in which the sensing voltage value is located, and the sensing voltage value is converted into an output signal of the pressure sensor by the analog-to-digital converter; and when the sensing voltage data reaches a corresponding reference value, a corresponding clamping voltage is generated by the analog-to-digital converter to realize accurate clamping of the output signal of the pressure sensor. The pressure sensor provided by the application effectively avoids the problem of insufficient clamping accuracy caused by clamping with a voltage stabilizing tube, and supports the system to quickly determine whether the pressure sensor is faulty through software.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of pressure sensor design, in particular to a pressure sensor and a fault positioning method thereof for realizing accurate correction and supporting software rapid fault positioning. BACKGROUND

[0002] In recent years, pressure sensors are widely used in various fields such as automobiles, energy storage, and industrial Internet of Things, and are one of the core components of intelligent sensing terminals.

[0003] In some application scenarios, the pressure sensor needs to control the upper and lower limit values of the voltage of its output signal to protect the electronic devices connected to its output terminal. For example, when the pressure sensor is applied in the field of automobiles and vacuum pressure equipment, the output voltage signal of the pressure sensor needs to be controlled within a specific range in order to protect the equipment manager (ECU) on the board and other electronic devices connected to its output terminal. With the improvement of system intelligence, the pressure sensor in the system is required to provide corresponding methods / ways to realize ECU software fault positioning.

[0004] Most of the existing pressure sensors do not have a clamping (voltage upper and lower limit value) function for the output signal, and a small part uses a voltage stabilizing tube for output signal clamping. When a voltage stabilizing tube is used for output signal clamping, the voltage stabilizing tube is greatly affected by temperature changes, resulting in poor clamping accuracy and easily leading to software misjudgment. Because the clamped voltage of the output signal of the pressure sensor deviates too much from the expected voltage value, the system generates false alarms. SUMMARY

[0005] In order to accurately clamp the output signal of the pressure sensor, realize software diagnosis of pressure sensor faults, and improve the accuracy of the output signal of the pressure sensor, the present application provides a pressure sensor. The pressure sensor uses the characteristic that the output signal of the digital-to-analog converter is almost not affected by temperature, and uses the accurate voltage generated thereby to clamp the output signal of the pressure sensor; and based on the corresponding clamped voltage as a reference standard for pressure sensor fault detection, the pressure sensor fault positioning is conveniently realized.

[0006] The first aspect of the present application provides a pressure sensor. The pressure sensor comprises a pressure sensing unit, a signal conditioning module, a digital-to-analog converter, and an analog-to-digital converter. In some embodiments, the signal conditioning module, the digital-to-analog converter, and the analog-to-digital converter are integrated in an ASIC chip.

[0007] The analog-to-digital converter is configured to convert an analog sensing voltage signal generated by the pressure sensing unit into a sensing voltage value. The pressure sensing unit can be a piezoresistor or the like, which is not limited herein. The signal conditioning module is configured to determine whether the sensing voltage value reaches a corresponding reference value. If yes, a corresponding first voltage is output by the digital-to-analog converter as an output signal of the pressure sensor based on the corresponding reference value. Otherwise, a corresponding conversion value is generated by the signal conditioning module based on the sensing voltage value to control the digital-to-analog converter to output a corresponding second voltage as the output signal of the pressure sensor.

[0008] To make the digital-to-analog converter output the first voltage that does not change with temperature, preferably, a reference voltage of the digital-to-analog converter is generated by a bandgap reference voltage source.

[0009] Further, the reference value includes an upper limit value and a lower limit value. Correspondingly, the first voltage includes a high clamping voltage corresponding to the upper limit value and a low clamping voltage corresponding to the lower limit value. Preferably, the signal conditioning module stores the reference value by using an OTP unit.

[0010] Further, the signal conditioning module is further configured to compensate and correct the sensing voltage value to generate the conversion value when determining that the sensing voltage value does not reach the preset reference value.

[0011] In some embodiments, the signal conditioning module further includes a correction straight line storage unit and a temperature compensation unit. The correction straight line storage unit stores a plurality of correction straight line functions. The signal conditioning module corrects the sensing voltage value by using a piecewise correction method, i.e., selecting a corresponding correction straight line function for correction according to a range in which the sensing voltage value is located.

[0012] Corresponding to the pressure sensor described above, a second aspect of the present application provides a fault positioning method of the pressure sensor. The fault positioning method includes continuously increasing or decreasing a voltage of a pressure input end of the analog-to-digital converter, and determining whether an output signal of the pressure sensor is clamped to a corresponding first voltage. If not (including no clamping and the clamped voltage being not the corresponding first voltage), it is determined that the pressure sensor is faulty.

[0013] The pressure sensor provided by the application corrects the output signal in a segmented correction manner, and the circuit connection relationship is simple; not only can accurate output signal be output, but also the pressure sensor output signal is accurately clamped to a specific voltage which is not affected by temperature. Further, based on the high clamping accuracy and high reliability of the output signal of the pressure sensor, the application also provides a method for accurately locating faults of the pressure sensor, meeting the requirement of intelligent system that the pressure sensor can be conveniently diagnosed by software. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 The structure schematic diagram of the pressure sensor provided by the application in one embodiment. DETAILED DESCRIPTION

[0015] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. The components of the embodiments of the application described and shown in the drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the application. Based on the embodiments of the application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the application.

[0016] As Figure 1 shown, the pressure sensor provided by the application in one embodiment includes a pressure sensing unit SEN, a pre-gain amplifier PGA, an analog-to-digital converter ADC, a signal conditioning chip ASIC, a digital-to-analog converter DAC and an output buffer Buffer.

[0017] In this embodiment, the output signal of the pressure sensing unit (SEN) is amplified by a pre-gain amplifier (PGA) and then converted into a corresponding sensed voltage value (digitized) by an analog-to-digital converter (DAC). The pressure sensing unit (SEN) can be a pressure-sensitive resistor, etc., and no limitation is made on its type. The sensed voltage value is processed by the signal conditioning chip (ASIC) for numerical correction, temperature compensation, etc., and then converted by the DAC to obtain the output signal of the entire pressure sensor (i.e., the analog voltage signal characterizing the pressure sensed by the pressure sensing unit SEN). In this embodiment, the output signal of the pressure sensor is output to other electronic components (e.g., a device management unit (ECU)) through an output buffer to enhance the load-carrying capacity of the pressure sensor output and to isolate external devices from interfering with the DAC through the pressure sensor output. In another embodiment, the DAC and ADC are integrated into the signal conditioning ASIC chip.

[0018] exist Figure 1 In the embodiment shown, the signal conditioning chip ASIC functionally includes a temperature compensation unit, a correction line storage unit, and a correction module. Figure 1 (Not shown in the diagram) and an OTP storage unit. The OTP storage unit stores the input value of the corresponding clamping voltage generated by the digital-to-analog converter (DAC), i.e., the reference value described below. The temperature compensation unit is used to perform temperature compensation on the sensed voltage value. The calibration line storage unit stores several calibration line functions. The calibration module selects the appropriate calibration line function for calibration based on the range of the sensed voltage value, i.e., it uses a piecewise calibration method to calibrate the sensed voltage value. Since a single calibration line cannot be applied to calibrate the sensed voltage value across the entire sensing range, selecting a suitable calibration line based on different segments of the sensed voltage data can effectively improve the accuracy of the calibration.

[0019] Furthermore, the process of outputting the pressure sensor signal includes: the signal conditioning chip ASIC (built-in program) determines whether the sensed voltage value obtained by the analog-to-digital converter (ADC) reaches the reference value stored in the OTP storage unit; if it does, the corresponding reference value is used to control the digital-to-analog converter (DAC) to output the corresponding first voltage (i.e., clamping voltage) as the output signal of the pressure sensor (i.e., using the corresponding reference value as the input value of the DAC); otherwise, the signal conditioning chip ASIC generates a corresponding conversion value based on the sensed voltage value to control the DAC to output the corresponding second voltage as the output signal of the pressure sensor.

[0020] Preferably, the reference voltage of the digital-to-analog converter (DAC) is generated by a bandgap reference voltage source. The voltage generated by the bandgap reference voltage source is stable and almost unaffected by environmental factors such as temperature. The digital-to-analog converter (DAC) uses a voltage dividing circuit network with symmetry characteristics to output a corresponding voltage signal according to the set reference voltage. Therefore, the reference voltage of the digital-to-analog converter (DAC) generated by the bandgap reference voltage source can ensure that the digital-to-analog converter (DAC) generates a first voltage (i.e., the clamping voltage of the pressure sensor output signal) accurately and stably.

[0021] Further, the reference value includes an upper limit value and a lower limit value. Correspondingly, the first voltage includes a high clamping voltage corresponding to the upper limit value and a low clamping voltage corresponding to the lower limit value. In this way, the requirement of some systems / devices that the pressure sensor output signal has an upper and lower limit can be met.

[0022] When the sensing voltage value converted by the analog-to-digital converter (ADC) does not reach the reference value stored in the OTP storage unit, the signal conditioning chip ASIC generates a corresponding conversion value based on the sensing voltage value to control the digital-to-analog converter (DAC) to output a corresponding second voltage, including: temperature compensation of the sensing voltage value, and the conversion value is obtained after the sensing voltage value is corrected by the correction module.

[0023] Corresponding to the above-mentioned pressure sensor, the second aspect of the present application also provides a fault positioning method of the above-mentioned pressure sensor. The fault positioning method includes: continuously increasing or decreasing the voltage of the pressure input end of the digital-to-analog converter (DAC) in one direction, and judging whether the output signal of the pressure sensor is clamped to a corresponding first voltage; if not (including not clamping and the clamping voltage being a non-corresponding first voltage), it is judged that the pressure sensor is faulty; otherwise, it is determined that the pressure sensor is working normally. Obviously, the above-mentioned fault positioning method only needs to detect and identify the output signal of the pressure sensor, and can be easily realized through a software program (for example, a detection program executed by the device manager ECU).

[0024] The above-mentioned pressure sensor circuit connection relationship provided by the present application is simple, which not only can improve the accuracy of the pressure sensor output signal, but also can ensure that the pressure sensor output signal is accurately and stably clamped to the set fixed voltage. Correspondingly, based on the pressure sensor fault positioning method provided by the above-mentioned pressure sensor, the probability of false judgment of the software system can be greatly reduced, and the requirement of the intelligent system that the pressure sensor can be conveniently diagnosed by software fault is met.

[0025] The above description is merely an embodiment of the present invention and is not intended to limit the invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for fault location of a pressure sensor, characterized in that, The pressure sensor includes: a pressure sensing unit, a signal conditioning module, a digital-to-analog converter (DAC), and an analog-to-digital converter (ADC). The ADC converts the analog sensing voltage signal generated by the pressure sensing unit into a sensing voltage value. The signal conditioning module determines whether the sensing voltage value reaches a corresponding reference value. If so, it uses the corresponding reference value to control the ADC to output a corresponding first voltage as the output signal of the pressure sensor. Otherwise, the signal conditioning module generates a corresponding conversion value based on the sensing voltage value to control the ADC to output a corresponding second voltage as the output signal of the pressure sensor. The ADC uses a symmetrical voltage divider network to output a corresponding voltage signal according to a set reference voltage, which is generated by a bandgap reference voltage source. The fault location method includes: continuously increasing or decreasing the voltage at the pressure input terminal of the analog-to-digital converter, and determining whether the output signal of the pressure sensor is clamped to a corresponding first voltage; if not, determining that the pressure sensor is faulty; the reference value includes an upper limit value and a lower limit value, and the first voltage includes a high clamping voltage corresponding to the upper limit value and a low clamping voltage corresponding to the lower limit value.

2. The fault location method as described in claim 1, characterized in that, The signal conditioning module includes an OTP unit for storing the reference values.

3. The fault location method as described in any one of claims 1-2, characterized in that, When the signal conditioning module determines that the sensed voltage value has not reached the preset reference value, it is also used to compensate and correct the sensed voltage value to generate the converted value.

4. The fault location method as described in claim 3, characterized in that, The signal conditioning module further includes a calibration line storage unit, which stores several calibration line functions; the signal conditioning module selects the appropriate calibration line function for calibration according to the range of the sensed voltage value.

5. The fault location method as described in claim 1, characterized in that, The signal conditioning module, digital-to-analog converter, and analog-to-digital converter are integrated into a single ASIC chip.

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