A pressure sensing device driven by a constant current source

Abstract

This utility model discloses a pressure sensing device driven by a constant current source, including a constant current source module, a sensing bridge module, a compensation module, and a conversion module. The constant current source module uses an operational amplifier chip to generate a constant current. Two pressure-sensitive resistors connected in series in the sensing bridge module generate an analog pressure signal based on the constant current measurement. Two temperature sensors in the compensation module work together to measure the temperature value, which is then used to obtain external power and differential signals from the external input terminal for temperature drift suppression. The conversion module converts the analog pressure signal into a digital pressure signal based on the differential signal and outputs it. Thus, the constant current source provides stable power, the sensing bridge stably performs pressure measurement, and the compensation module drives the constant current source module to perform temperature drift suppression based on temperature changes, effectively compensating for measurement errors caused by resistance changes. This allows for wide applicability to various application scenarios, eliminating measurement errors. The conversion module converts the analog pressure signal into a digital pressure signal and performs linear fitting, further improving output accuracy.

Description

Technical Field

[0001] This utility model relates to the field of circuit design technology, and in particular to a pressure sensing device based on constant current source drive. Background Technology

[0002] Exhaust back pressure directly reflects the resistance pressure of a vehicle's engine exhaust, allowing for the assessment of the engine and exhaust system's operating conditions and timely detection of faults. Therefore, sensors for measuring exhaust back pressure need to be able to operate stably for extended periods under harsh conditions of high temperature and pressure. However, existing pressure sensors for exhaust back pressure measurement mostly employ the Wheatstone bridge principle, which is sensitive to power supply fluctuations. The bridge output error is significantly affected by power supply voltage fluctuations, and temperature drift also exists, amplifying the measurement error as the resistance value changes with temperature. Furthermore, the measurement results suffer from poor linearity. It is evident that existing pressure sensors do not consider special operating environments and harsh conditions, lacking adaptability to various environments and resulting in relatively large measurement errors. Utility Model Content

[0003] An embodiment of this utility model discloses a pressure sensing device based on a constant current source drive, specifically including: Constant current source module, sensor bridge module, compensation module and conversion module; The constant current source module uses operational amplifier chip U11 to generate a constant current; The pressure-sensitive resistors R63 and R64 connected in series in the sensing bridge module generate a simulated pressure signal based on the constant current measurement. The compensation module includes temperature sensor U3, temperature sensor U9 and terminal J9. Temperature sensor U3 and temperature sensor U9 work together to measure the temperature value for the constant current source module to perform temperature drift suppression. Terminal J9 acquires external power supply and differential signal input. The conversion module uses an analog-to-digital converter chip U5, which converts the analog pressure signal into a digital pressure signal based on the differential signal and outputs it.

[0004] As an optional implementation, pins 3 and 5 of the operational amplifier chip U11 are connected to both ends of the pressure-sensitive resistor R63, and one end of the pressure-sensitive resistor R63 is grounded through the pressure-sensitive resistor R64.

[0005] As an optional implementation, the first pin of the terminal J9 is connected to an external power supply and input to the first pin of the operational amplifier chip U11, and the fourth pin of the operational amplifier chip U11 is grounded through the second pin of the terminal J9.

[0006] As an optional implementation, the temperature sensor U3 and the temperature sensor U9 respectively measure the surface temperature of the pressure-sensitive resistor R63 and the pressure-sensitive resistor R64; The second pin of the temperature sensor U3 is connected to the second pin of the temperature sensor U9, and together they output the temperature value indicating the surface temperature of the pressure-sensitive resistor R63 and the pressure-sensitive resistor R64.

[0007] As an optional implementation, the operational amplifier chip U11 performs automatic temperature drift suppression based on the temperature value.

[0008] As an optional implementation, the third pin of the analog-to-digital converter chip U5 is connected to the third pin of the terminal J9, and the fourth pin of the analog-to-digital converter chip U5 is connected to the fourth pin of the terminal J9, for receiving differential signals carrying external commands.

[0009] As an optional implementation, based on the differential signal, the analog-to-digital converter chip U5 converts the analog pressure signal into a digital pressure signal; The digital pressure signal is output from pin 6 of the analog-to-digital converter chip U5, and a clock signal corresponding to the digital pressure signal is output from pin 5.

[0010] Compared with the prior art, this embodiment has the following beneficial effects: In this embodiment, a constant current source provides stable power, a sensing bridge stably performs pressure measurement, and a compensation module drives the constant current source module to perform temperature drift suppression based on temperature changes, effectively compensating for measurement errors caused by resistance changes. This can be widely adapted to various application scenarios, eliminating measurement errors. The conversion module converts the analog pressure signal into a digital pressure signal and performs linear fitting, further improving output accuracy. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in this embodiment, the accompanying drawings used in the embodiment will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of the circuit principle of the constant current source module and the sensing bridge module in a pressure sensing device driven by a constant current source disclosed in this embodiment. Figure 2 This is a schematic diagram of the circuit principle of the compensation module in a pressure sensing device driven by a constant current source disclosed in this embodiment. Figure 3This is a schematic diagram of the circuit principle of the conversion module in a pressure sensing device driven by a constant current source disclosed in this embodiment. Detailed Implementation

[0013] The technical solutions in this embodiment will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0014] Please see Figures 1-3 This embodiment discloses a pressure sensing device based on a constant current source drive, comprising: Constant current source module, sensor bridge module, compensation module and conversion module; The constant current source module uses the operational amplifier chip U11 to generate a constant current; The pressure-sensitive resistors R63 and R64 connected in series in the sensing bridge module generate a simulated pressure signal based on constant current measurement. The compensation module includes temperature sensor U3, temperature sensor U9 and terminal J9. Temperature sensor U3 and temperature sensor U9 work together to measure the temperature value for the constant current source module to perform temperature drift suppression. Terminal J9 acquires external power supply and differential signal input. The conversion module uses the U5 analog-to-digital converter chip, which is based on differential signals and converts analog pressure signals into digital pressure signals for output.

[0015] In this embodiment, the constant current source module generates a constant current to achieve stable power supply and avoid amplifying the measurement error of the sensing bridge module due to power supply fluctuations.

[0016] Furthermore, the compensation module measures the temperature value, which is then used by the constant current source module to perform temperature drift suppression, effectively compensating for measurement errors caused by resistance changes. This reduces the impact of temperature changes on measurement accuracy and expands the application scenarios.

[0017] In addition, a conversion module is used to convert the measured analog pressure values ​​into digital pressure signals and perform linear fitting to obtain accurate and highly linear output results, further improving the accuracy of the measurement output.

[0018] As an optional implementation, pins 3 and 5 of the operational amplifier chip U11 are connected to both ends of the pressure-sensitive resistor R63, and one end of the pressure-sensitive resistor R63 is grounded through the pressure-sensitive resistor R64.

[0019] Here, the four arms are matched based on two pressure-sensitive resistors, so that when the resistance of any pressure-sensitive resistor changes due to pressure, the operational amplifier chip U11 can know the pressure change accordingly.

[0020] As an optional implementation, pin 1 of terminal J9 is connected to an external power supply and input to pin 1 of operational amplifier chip U11, and pin 4 of operational amplifier chip U11 is grounded via pin 2 of terminal J9.

[0021] Here, terminal J9 obtains external power to supply the overall operation of the system.

[0022] As an optional implementation, temperature sensor U3 and temperature sensor U9 respectively measure the surface temperature of pressure-sensitive resistor R63 and pressure-sensitive resistor R64; The second pin of temperature sensor U3 is connected to the second pin of temperature sensor U9, and together they output the temperature values ​​indicating the surface temperature of pressure-sensitive resistors R63 and R64.

[0023] As an optional implementation, the operational amplifier chip U11 performs automatic temperature drift suppression based on the temperature value.

[0024] Here, two temperature sensors can perform temperature measurements on two pressure-sensitive resistors separately, effectively avoiding the high failure rate and high measurement error that may occur with a single sensor.

[0025] As an optional implementation, pin 3 of analog-to-digital converter chip U5 is connected to pin 3 of terminal J9, and pin 4 of analog-to-digital converter chip U5 is connected to pin 4 of terminal J9 to receive differential signals carrying external commands.

[0026] As an optional implementation, based on differential signals, the analog-to-digital converter chip U5 converts the analog pressure signal into a digital pressure signal; Pin 6 of the analog-to-digital converter chip U5 outputs a digital pressure signal, and pin 5 outputs a clock signal corresponding to the digital pressure signal.

[0027] Here, the differential signal is emitted by an external device that receives the digital pressure signal. Based on the usage requirements, it outputs the differential signal to drive the analog-to-digital converter chip U5 to convert the currently received analog pressure signal into a digital pressure signal and output it in sequence.

[0028] Compared with the prior art, this embodiment has the following beneficial effects: In this embodiment, a constant current source provides stable power, a sensing bridge stably performs pressure measurement, and a compensation module drives the constant current source module to perform temperature drift suppression based on temperature changes, effectively compensating for measurement errors caused by resistance changes. This can be widely adapted to various application scenarios, eliminating measurement errors. The conversion module converts the analog pressure signal into a digital pressure signal and performs linear fitting, further improving output accuracy.

Claims

1. A pressure sensing device based on constant current source driving, characterized in that, include: Constant current source module, sensor bridge module, compensation module and conversion module; The constant current source module uses operational amplifier chip U11 to generate a constant current; The pressure-sensitive resistors R63 and R64 connected in series in the sensing bridge module generate a simulated pressure signal based on the constant current measurement. The compensation module includes temperature sensor U3, temperature sensor U9 and terminal J9. Temperature sensor U3 and temperature sensor U9 work together to measure the temperature value for the constant current source module to perform temperature drift suppression. Terminal J9 acquires external power supply and differential signal input. The conversion module uses an analog-to-digital converter chip U5, which converts the analog pressure signal into a digital pressure signal based on the differential signal and outputs it.

2. The pressure sensing device based on constant current source driving according to claim 1, characterized in that, include: Pins 3 and 5 of the operational amplifier chip U11 are connected to both ends of the pressure-sensitive resistor R63, and one end of the pressure-sensitive resistor R63 is grounded through the pressure-sensitive resistor R64.

3. The pressure sensing device based on constant current source driving according to claim 1, wherein, include: The first pin of terminal J9 is connected to an external power supply and input to the first pin of operational amplifier chip U11. The fourth pin of operational amplifier chip U11 is grounded through the second pin of terminal J9.

4. The pressure sensing device based on constant current source driving according to claim 1, characterized in that, include: The temperature sensor U3 and the temperature sensor U9 respectively measure the surface temperature of the pressure-sensitive resistor R63 and the pressure-sensitive resistor R64; The second pin of the temperature sensor U3 is connected to the second pin of the temperature sensor U9, and together they output the temperature value indicating the surface temperature of the pressure-sensitive resistor R63 and the pressure-sensitive resistor R64.

5. The pressure sensing device based on constant current source driving according to claim 4, characterized in that, include: Based on the temperature value, the operational amplifier chip U11 performs automatic temperature drift suppression.

6. The pressure sensing device based on constant current source driving according to claim 1, wherein, include: The third pin of the analog-to-digital converter chip U5 is connected to the third pin of the terminal J9, and the fourth pin of the analog-to-digital converter chip U5 is connected to the fourth pin of the terminal J9, for receiving differential signals carrying external commands.

7. The pressure sensing device based on constant current source driving according to claim 6, characterized in that, include: Based on the differential signal, the analog-to-digital converter chip U5 converts the analog pressure signal into a digital pressure signal; The digital pressure signal is output from pin 6 of the analog-to-digital converter chip U5, and a clock signal corresponding to the digital pressure signal is output from pin 5.

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