A temperature sensor pressure drop testing device

Abstract

The utility model provides a kind of temperature sensor voltage drop testing device, belong to sensor test technical field, comprising: temperature sensor module, including temperature sensor integrated on measured object;Constant-current excitation module, the output end of constant-current excitation module is connected temperature sensor module;Common-mode rejection amplification module, the input end of common-mode rejection amplification module is electrically connected with the both ends of temperature sensor respectively;Calibration module, respectively connect common-mode rejection amplification module and digitizing output module;Power module, respectively connect constant-current excitation module, common-mode rejection amplification module and calibration module.Affirmative effect: by temperature sensor directly integrated on test object, the temperature of test object surface can be more accurately reflected;At the same time, through the integrated design of constant-current excitation, high common-mode rejection amplification and calibration, low-noise amplification and high-precision test of temperature sensor voltage drop signal are realized, and the reliability and accuracy of test are improved.

Description

Technical Field

[0001] This utility model relates to the field of sensor testing technology, and in particular to a temperature sensor pressure drop testing device. Background Technology

[0002] With the widespread application of power modules in various electronic devices and industrial systems, the requirements for their performance, reliability, and safety are also increasing. Temperature sensors, as an indispensable component of power modules, have gradually become standard equipment.

[0003] Temperature sensors in power modules are primarily used to monitor and control the internal temperature of the module, preventing damage to components due to overheating and ensuring stable operation of the power module. Compared to external sensors, integrated sensors offer greater cost-effectiveness, provide users with additional protection functions such as over-temperature protection, and reduce module size, meeting the miniaturization and integration demands of electronic devices.

[0004] For device protection, various types of temperature sensors are available, among which temperature sensors with negative temperature coefficient (NTC) or positive temperature coefficient (PTC) thermistors are widely used. NTC thermistors, with their excellent performance and wide applicability, are the most commonly used type of temperature sensor in standard industrial modules. The sensor's location within the module significantly affects its temperature protection capability. In fact, the sensor's location is even more critical than the sensor's inherent error, especially when the hardware open-circuit level is set by the driver or control circuitry.

[0005] like Figure 1 As shown, the existing temperature sensor voltage drop test circuit consists of a voltage source U1, a resistor R1, and a temperature sensor D1 connected in series. This circuit has low test accuracy and is easily affected by the series resistance and the accuracy of the output voltage. It is also susceptible to interference from parasitic inductance and capacitance, causing the current flowing through the temperature sensor to fluctuate easily, thus limiting the accuracy of the measured voltage. Utility Model Content

[0006] To address the above technical problems, this utility model provides a temperature sensor pressure drop testing device.

[0007] The technical problem solved by this utility model can be achieved by the following technical solution: A temperature sensor pressure drop testing device, comprising: Temperature sensor module, including a temperature sensor integrated on the object being measured; A constant current excitation module, the output of which is connected to the temperature sensor module; A common-mode rejection amplifier module, wherein the input terminals of the common-mode rejection amplifier module are electrically connected to the two ends of the temperature sensor respectively; The calibration module is connected to the common-mode rejection amplification module and the digital output module, respectively. The power supply module is connected to the constant current excitation module, the common mode rejection amplification module, and the calibration module, respectively.

[0008] Preferably, the temperature sensor is a diode.

[0009] Preferably, the constant current excitation module includes: A constant current source chip, wherein the anode of the constant current source chip is connected to one end of the temperature sensor and the reference terminal of the constant current source chip is connected through a sampling resistor, and the other end of the temperature sensor is grounded; The first transistor has its base connected to the cathode of the constant current source chip, its emitter connected to the reference terminal of the constant current source chip, and its collector connected to the signal input terminal. A resistor is connected between the base and collector of the first transistor.

[0010] Preferably, the output current of the constant current excitation module is 0.1mA~100mA.

[0011] Preferably, the common-mode suppression amplification module includes: An amplifier is provided, with its non-inverting and inverting inputs connected to the two ends of the temperature sensor, and its output connected to the calibration module.

[0012] Preferably, the common-mode suppression amplification module further includes: An adjustable resistor is connected to the gain adjustment terminal of the amplifier.

[0013] Preferably, the gain adjustment range of the common-mode suppression amplification module is 1 to 1000 times.

[0014] Preferably, the calibration module includes: The first calibration unit is electrically connected to the zero-adjustment terminal of the common-mode rejection amplifier module; The second calibration unit includes a microcontroller and a storage subunit pre-stored with a temperature and pressure drop mapping table. The microcontroller is connected to the storage subunit and the digital output module, respectively.

[0015] Preferably, the power module includes: The first linear voltage regulator unit has its input terminal connected to AC power, and its output terminal connected to the constant current excitation module, the common mode rejection amplification module, and the calibration module, respectively. The first filter network unit is connected between the input terminal and the ground terminal of the first linear regulator unit; The second linear voltage regulator unit has its input terminal connected to AC power, and its output terminal connected to the constant current excitation module, the common mode rejection amplification module, and the calibration module, respectively. The second filter network unit is connected between the input terminal of the second linear regulator unit and the ground terminal.

[0016] Preferably, the digital output module includes: An analog-to-digital converter unit, wherein the input terminal of the analog-to-digital converter unit is connected to the output terminal of the common-mode rejection amplifier module; A communication unit is provided, which is connected to the output of the analog-to-digital conversion unit and an external device.

[0017] The advantages or beneficial effects of this utility model's technical solution are as follows: This invention integrates the temperature sensor directly onto the test object, enabling a more accurate reflection of the object's surface temperature. Furthermore, through the integrated design of constant current excitation, high common-mode rejection amplification, and calibration, it achieves low-noise amplification and high-precision testing of the temperature sensor's voltage drop signal, thereby improving the reliability and accuracy of the test. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a temperature sensor voltage drop test circuit in the prior art; Figure 2 This is a schematic diagram of the structure of the temperature sensor pressure drop testing device in a preferred embodiment of the present invention. Figure 3 This is a schematic diagram of a half-bridge circuit equipped with a temperature sensor in a preferred embodiment of the present invention. Figure 4 This is a circuit diagram of the transverse current excitation module in a preferred embodiment of the present invention. Figure 5 This is a circuit diagram of the common-mode suppression amplification module in a preferred embodiment of the present invention. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments of the present invention can be combined with each other.

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention.

[0022] See Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 In a preferred embodiment of this utility model, based on the aforementioned problems existing in the prior art, a temperature sensor voltage drop testing device is provided. This device includes a temperature sensor module 1, a constant current excitation module 2, a common-mode rejection amplification module 3, a calibration module 4, a digital output module 5, and a power supply module 6. By optimizing and improving the circuit structure, the accuracy of temperature sensor voltage drop testing is improved.

[0023] like Figure 2 and Figure 3 As shown, the device includes: Temperature sensor module 1 includes a temperature sensor 11 integrated on the object being measured, used to sense the temperature of the object being measured and output a temperature-related voltage drop signal across two terminals. The output of constant current excitation module 2 is connected to temperature sensor module 1 to provide a stable constant current source to temperature sensor module 1, ensuring that the voltage drop signal is only related to temperature. The common-mode rejection amplifier module 3 has its input terminals electrically connected to both ends of the temperature sensor 11, and is used to amplify the voltage drop signal and suppress common-mode noise. The calibration module 4 is connected to the common-mode rejection amplifier module 3 and the digital output module 5 respectively, and is used to eliminate amplifier offset voltage, gain error and sensor nonlinearity error; The digital output module 5 is used to convert the amplified and calibrated analog voltage drop signal output by the calibration module 4 into a digital signal and output it. The power supply module 6 is connected to the constant current excitation module 2, the common mode rejection amplifier module 3, and the calibration module 4 respectively, and is used to provide a stable DC power supply to the constant current excitation module 2, the common mode rejection amplifier module 3, and the calibration module 4.

[0024] Specifically, existing temperature sensor voltage drop test circuits suffer from low accuracy, susceptibility to series resistance and output voltage accuracy, and interference from parasitic inductance and capacitance, leading to significant fluctuations in the current flowing through the temperature sensor and limiting measurement accuracy. In this embodiment, temperature sensor module 1 directly integrates temperature sensor 11 onto the test object, enabling more accurate reflection of the object's surface temperature. Constant current excitation module 2 is connected in series with temperature sensor module 1, the input of common-mode rejection amplification module 3 is connected to both ends of temperature sensor module 1, and calibration module 4 is electrically connected to common-mode rejection amplification module 3 and digital output module 5. Through the integrated design of constant current excitation, high common-mode rejection amplification, and dual-dimensional calibration, low-noise amplification and high-precision testing of the temperature sensor voltage drop signal are achieved, improving the reliability and accuracy of the test.

[0025] The object being measured refers to a chip, circuit, instrument, electronic device, or other device that integrates a temperature sensor.

[0026] Furthermore, the temperature sensor 11 involved in this invention is not a traditional NTC thermistor sensor, but a temperature sensor 11 integrated on the test object. The position of this temperature sensor 11 in an existing half-bridge circuit is as follows... Figure 3 As shown, both the upper and lower bridges are equipped with temperature sensors 11. These temperature sensors 11 are preferably implemented using diodes, with the cathode of the diode connected to the source of the upper / lower bridge arm transistor.

[0027] Compared to traditional NTC thermistor sensors, this temperature sensor 11 is directly integrated on the chip, enabling it to more accurately reflect the chip surface temperature.

[0028] In a preferred embodiment, such as Figure 4 and Figure 5 As shown, temperature sensor 11 is diode D2.

[0029] Specifically, in this embodiment, diode D2 is selected as the temperature sensor. Based on its own physical characteristics, diode D2 has a linear relationship between its forward voltage drop and temperature. When the temperature changes, the forward voltage drop of diode D2 will change accordingly. By measuring the voltage drop signal across its terminals related to temperature, the current temperature of the object being measured can be accurately inferred.

[0030] In this embodiment, the diode D2 is preferably selected from ordinary PN junction diodes, Schottky diodes, Zener diodes, base-emitter junction diodes, diode-connected transistors, etc.

[0031] In a preferred embodiment, such as Figure 4 As shown, the constant current excitation module 2 includes: The constant current source chip IC1 has its anode connected to one end of the temperature sensor 11 and its reference terminal connected to the constant current source chip IC1 through the sampling resistor R3. The other end of the temperature sensor 11 is grounded. The first transistor Q1 has its base connected to the cathode of the constant current source chip IC1, its emitter connected to the reference terminal of the constant current source chip IC1, and its collector connected to the signal input terminal Vin. Resistor R2 is connected between the base and collector of the first transistor Q1.

[0032] In this embodiment, the constant current source chip IC1 is preferably selected as the TL431 chip. The TL431 chip is a commonly used adjustable reference voltage source with advantages such as high precision and low temperature coefficient, which can provide a stable and reliable reference voltage for the module.

[0033] In this embodiment, the first transistor Q1 is preferably an NPN transistor.

[0034] Specifically, in this embodiment, the constant current excitation module 2 mainly includes a constant current source chip IC1, an NPN type first transistor Q1, and a sampling resistor R3. The output current is controlled by utilizing the characteristic that the voltage between the reference terminal and the anode of the constant current source chip IC1 is constant at 2.5V.

[0035] In a preferred embodiment, the output current of the constant current excitation module 2 is 0.1mA~100mA, which can meet the working requirements of different types of temperature sensors 11. In practical applications, the output current of the constant current excitation module 2 can be flexibly adjusted according to the characteristics of the specific temperature sensor 11 and the system requirements to achieve the best measurement effect.

[0036] In a preferred embodiment, such as Figure 5 As shown, the common-mode rejection amplification module 3 includes: Amplifier U2 has its non-inverting and inverting input terminals connected to the two ends of temperature sensor 11, and its output terminal connected to calibration module 4.

[0037] Specifically, in this embodiment, amplifier U2 amplifies the temperature-related voltage drop signal across diode D2 while suppressing common-mode interference, thereby improving signal quality and measurement accuracy.

[0038] In this embodiment, amplifier U2 is preferably an instrumentation amplifier. Instrumentation amplifiers have advantages such as high input impedance, low output impedance, and good common-mode rejection ratio (CMRR), which can effectively suppress common-mode interference and improve the amplification accuracy of signals.

[0039] The preferred instrumentation amplifier is the AD623, which has a common-mode rejection ratio (CMRR) of ≥120dB.

[0040] In a preferred embodiment, the common-mode suppression amplification module 3 further includes: The adjustable resistor R4 is connected to the gain adjustment terminal of amplifier U2.

[0041] In a preferred embodiment, the gain adjustment range of the common-mode suppression amplification module 3 is 1 to 1000 times.

[0042] Specifically, in this embodiment, a precision adjustable resistor R4 is connected to the gain adjustment terminals of amplifier U2, namely pins 1 and 8. By adjusting the resistance value of the adjustable resistor R4, the gain of amplifier U2 can be adjusted within the range of 1 to 1000 times. By flexibly changing the gain of amplifier U2, it can adapt to temperature sensor signals of various intensities and meet the signal amplification requirements of different application scenarios.

[0043] In a preferred embodiment, the calibration module 4 includes: The first calibration unit is electrically connected to the zero-adjustment terminal of the common-mode rejection amplification module 3; The second calibration unit includes a microcontroller and a storage subunit containing a pre-stored temperature and pressure drop mapping table. The microcontroller is connected to both the storage subunit and the digital output module.

[0044] Specifically, in this embodiment, the calibration module 4 includes a first calibration unit and a second calibration unit, and adopts a dual calibration mode to calibrate the signal from the common-mode rejection amplifier module 3 to eliminate amplifier offset voltage, gain error and sensor nonlinearity error.

[0045] The first calibration unit is electrically connected to the zero-adjustment terminal (pin 5 of AD623) of the common-mode rejection amplification module 3. The first calibration unit uses a multi-turn precision potentiometer (Rw), which features high precision, a wide adjustment range, and finely controllable adjustment accuracy. During the operation of amplifier U2, offset voltage is generated due to differences in the characteristics of its internal components and limitations in the manufacturing process. In this embodiment, the amplifier offset voltage is eliminated by adjusting the resistance value of the potentiometer, keeping it within a very small range, such as Vos ≤ 5μV.

[0046] The second calibration unit includes a microcontroller (MCU) and a storage subunit. The microcontroller is connected to both the storage subunit and the digitization output module. In this embodiment, the preferred microcontroller (MCU) is an STM32F407. The storage subunit pre-stores a temperature and pressure drop mapping table calibrated using a standard temperature source (such as a FLUKE5520A). The microcontroller uses linear interpolation to correct the nonlinearity error of the temperature sensor, controlling the sensor's nonlinearity to be less than or equal to 0.05%.

[0047] Digital output module 5 connects to the integrated circuit bus (Inter-Integrated Circuit, I...) 2 C) The interface connects to the microcontroller. 2 The I2C interface is a serial bus protocol, which has advantages such as simplicity, high efficiency, and low pin usage. Through the I2C interface, the microcontroller can transmit the calibrated temperature data to the digital output module 5 for subsequent display, storage, or further data processing.

[0048] In a preferred embodiment, the power supply module 6 includes: The first linear voltage regulator unit has its input terminal connected to AC power and its output terminal connected to the constant current excitation module 2, the common mode rejection amplifier module 3, and the calibration module 4, respectively. The first filter network unit is connected between the input terminal and the ground terminal of the first linear voltage regulator unit; The second linear voltage regulator unit has its input terminal connected to AC power and its output terminal connected to the constant current excitation module 2, the common mode rejection amplifier module 3, and the calibration module 4, respectively. The second filter network unit is connected between the input terminal and the ground terminal of the second linear regulator unit.

[0049] In this embodiment, the first linear voltage regulator unit includes a first linear voltage regulator, preferably an LM7805, which is used to output a positive regulated voltage, preferably +5V.

[0050] In this embodiment, the second linear voltage regulator unit includes a second linear voltage regulator, preferably an LM7905, which is used to output a negative regulated voltage, preferably -5V.

[0051] Both the first and second filter network units are power supply filter networks. The power supply filter network consists of electrolytic capacitors and ceramic capacitors connected in parallel. They are respectively connected between the input terminal and the ground terminal of the first linear regulator unit and between the input terminal and the ground terminal of the second linear regulator unit. They are used to filter out power supply ripple and limit the ripple voltage to ≤10mV.

[0052] In this embodiment, the capacitance of the electrolytic capacitor is preferably 10μF, and the capacitance of the ceramic capacitor is preferably 0.1μF.

[0053] In a preferred embodiment, the digital output module 5 includes: The analog-to-digital converter (ADC) has its input connected to the output of the common-mode rejection amplifier (CMPA) module. The communication unit connects to the output of the analog-to-digital converter and external devices.

[0054] Specifically, in this embodiment, the digital output module 5 includes an analog-to-digital converter (ADC) unit and a communication unit; wherein, the ADC unit uses a 16-bit ADC chip, the differential input terminal of the 16-bit ADC chip is connected to the output terminal of the common-mode rejection amplifier module 3, and the output terminal is connected via I... 2 The C interface connects to the microcontroller.

[0055] In this embodiment, the preferred 16-bit analog-to-digital converter chip is the ADS1115.

[0056] The communication unit uses wired communication methods such as serial communication to convert digital signals into RS232 standard signals for output to the host computer. The MAX3232 chip is preferred for serial communication.

[0057] The communication unit can also use wireless communication methods such as WiFi or Bluetooth Low Energy to establish communication with external devices.

[0058] The above are merely preferred embodiments of the present utility model and are not intended to limit the implementation methods and protection scope of the present utility model. Those skilled in the art should realize that any equivalent substitutions and obvious changes made using the content of this specification and illustrations should be included within the protection scope of the present utility model.

Claims

1. A temperature sensor pressure drop testing device, characterized in that, include: Temperature sensor module, including a temperature sensor integrated on the object being measured; A constant current excitation module, the output of which is connected to the temperature sensor module; A common-mode rejection amplifier module, wherein the input terminals of the common-mode rejection amplifier module are electrically connected to the two ends of the temperature sensor respectively; The calibration module is connected to the common-mode rejection amplification module and the digital output module, respectively. The power supply module is connected to the constant current excitation module, the common mode rejection amplification module, and the calibration module, respectively.

2. The temperature sensor pressure drop testing device according to claim 1, characterized in that, The temperature sensor is a diode.

3. The temperature sensor pressure drop testing device according to claim 1, characterized in that, The constant current excitation module includes: A constant current source chip, wherein the anode of the constant current source chip is connected to one end of the temperature sensor and the reference terminal of the constant current source chip is connected through a sampling resistor, and the other end of the temperature sensor is grounded; The first transistor has its base connected to the cathode of the constant current source chip, its emitter connected to the reference terminal of the constant current source chip, and its collector connected to the signal input terminal. A resistor is connected between the base and collector of the first transistor.

4. The temperature sensor pressure drop testing device according to claim 1, characterized in that, The output current of the constant current excitation module is 0.1mA~100mA.

5. The temperature sensor pressure drop testing device according to claim 1, characterized in that, The common-mode suppression amplification module includes: An amplifier is provided, with its non-inverting and inverting inputs connected to the two ends of the temperature sensor, and its output connected to the calibration module.

6. The temperature sensor pressure drop testing device according to claim 5, characterized in that, The common-mode suppression amplification module further includes: An adjustable resistor is connected to the gain adjustment terminal of the amplifier.

7. The temperature sensor pressure drop testing device according to claim 1, characterized in that, The gain adjustment range of the common-mode suppression amplification module is 1 to 1000 times.

8. The temperature sensor pressure drop testing device according to claim 1, characterized in that, The calibration module includes: The first calibration unit is electrically connected to the zero-adjustment terminal of the common-mode rejection amplifier module; The second calibration unit includes a microcontroller and a storage subunit pre-stored with a temperature and pressure drop mapping table. The microcontroller is connected to the storage subunit and the digital output module, respectively.

9. The temperature sensor pressure drop testing device according to claim 1, characterized in that, The power module includes: The first linear voltage regulator unit has its input terminal connected to AC power, and its output terminal connected to the constant current excitation module, the common mode rejection amplification module, and the calibration module, respectively. The first filter network unit is connected between the input terminal and the ground terminal of the first linear regulator unit; The second linear voltage regulator unit has its input terminal connected to AC power, and its output terminal connected to the constant current excitation module, the common mode rejection amplification module, and the calibration module, respectively. The second filter network unit is connected between the input terminal of the second linear regulator unit and the ground terminal.

10. The temperature sensor pressure drop testing device according to claim 1, characterized in that, The digital output module includes: An analog-to-digital converter unit, wherein the input terminal of the analog-to-digital converter unit is connected to the output terminal of the common-mode rejection amplifier module; A communication unit is provided, which is connected to the output of the analog-to-digital conversion unit and an external device.

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