Resistance-type pressure sensor current excitation test tool
By designing a current-excitation test fixture for resistive pressure sensors and employing a high-precision constant current source circuit and multi-channel expansion technology, the problems of limited sensor testing quantity and high cost in existing technologies have been solved, enabling efficient and accurate batch testing of multiple sensors and simulation of real-world environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-27
- Publication Date
- 2026-03-27
AI Technical Summary
Existing resistance pressure sensor testing methods can only test three sensors at a time, resulting in a small number of tests and high costs, which cannot meet the needs of batch testing.
A current excitation test fixture for a resistive pressure sensor was designed. It adopts a high-precision constant current source circuit (LM134 chip) and replicates a single-channel constant current source circuit to achieve multi-channel expansion. It is equipped with a pneumatic pump to simulate the actual pressure environment and combines an analog-to-digital converter to achieve automated data recording.
It enables efficient and accurate testing of multiple sensors, improving testing efficiency and accuracy, supporting batch testing, simulating real-world application environments, and digitizing data records.
Smart Images
Figure CN224051501U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to sensor manufacturing technical field more specifically, it relates to a kind of resistance pressure sensor current excitation test tool. BACKGROUND
[0002] The test of resistance pressure sensor refers to the performance, accuracy, stability and reliability of sensor are verified whether meet design requirements and application standard by a series of experiments and measurement means.The working principle of resistance pressure sensor is usually based on piezoresistive effect, that is, when external pressure acts on sensor, the resistance value of sensor will change, and the pressure value can be indirectly obtained by measuring the change of resistance value.Therefore, the core goal of test is to ensure that sensor can accurately and stably output corresponding resistance value under different pressure conditions.
[0003] The existing measurement method is to use direct current source to provide current.The measured sensor is connected together in series, and series connection ensures that the current of all tested sensors is 1mA.The maximum output voltage when direct current power supplies current is, for example, 15V, the resistance of one piezoresistive sensor is 5kΩ, and the current is 1mA, so at most only 3 piezoresistive sensors can be connected in series for testing.Only 3 piezoresistive sensors can be tested by one current source.The test quantity is too small, and the test cost is high. UTILITY MODEL CONTENT
[0004] In view of the deficiencies in the prior art, the utility model aims to provide a resistance pressure sensor current excitation test tool which can measure multiple sensors at a time.
[0005] To achieve the above-mentioned purpose, the utility model provides the following technical scheme:
[0006] A resistance pressure sensor current excitation test tool, characterized by comprising a test tool main body and a test circuit,
[0007] The test tool main body comprises a shell and a mounting bracket for mounting the resistance pressure sensor, the mounting bracket has multiple and annularly distributes in the shell, and the mounting bracket is provided with a USB interface connected with the resistance pressure sensor at one end,
[0008] The shell is provided with an air pressure pump above, the air pressure pump is connected with a contact head at the output end, and the contact head is used for connecting with the pressure interface of the resistance pressure sensor,
[0009] The sidewall of the shell is provided with an analog-to-digital converter, and the analog-to-digital converter is in communication connection with the resistance pressure sensor,
[0010] The test circuit comprises a power supply +VIN, a transistor SE, a resistor VR, a bias voltage source BIAS, a transistor R1, a transistor R2 and a diode VD, the power supply +VIN is connected with the base of the transistor SE,
[0011] The resistor VR is connected with the base of the transistor SE,
[0012] The bias voltage source BIAS is connected with the base of the transistor SE, and a stable DC bias voltage is provided.
[0013] The transistor R1, the transistor R2 and the diode VD are connected in parallel.
[0014] The utility model further sets up: the quantity of power supply circuit is 10 ways, uses 1 only LM134 chip every way, realizes multichannel extension through copying single channel constant current source circuit.
[0015] The utility model further sets up: the model that diode VD adopts is 1N4148.
[0016] The utility model further sets up: power supply +VIN adopts flow source chip LM134 and makes 1mA constant current source.
[0017] The utility model further sets up: the pressure difference between working voltage and output terminal voltage is greater than 1V.
[0018] Compared with the prior art, the utility model has the beneficial effects that:
[0019] 1, by using high-precision constant current source circuit (such as LM134 chip), the stability of sensor excitation current and the high signal-to-noise ratio of output signal are ensured, so as to improve the test precision;
[0020] 2, by copying single channel constant current source circuit and control circuit, multichannel extension is realized, batch testing is supported, and test efficiency is significantly improved;
[0021] 3, by air pressure pump simulation sensor in actual application pressure environment, the performance of sensor is comprehensively verified;
[0022] 4, by analog-digital converter, the automation of test process and the digitization of data record are realized. BRIEF DESCRIPTION OF DRAWINGS
[0023] Figure 1 It is the structural schematic diagram of the utility model embodiment;
[0024] Figure 2 It is the first circuit diagram of the utility model embodiment;
[0025] Figure 3 It is the second circuit diagram of the utility model embodiment;
[0026] Figure 4 The third circuit diagram of the embodiment of the utility model;
[0027] Figure 5 The fourth circuit diagram of the embodiment of the utility model;
[0028] Figure 6 The fifth circuit diagram of the embodiment of the utility model;
[0029] Figure 7 The sixth circuit diagram of the embodiment of the utility model;
[0030] Figure 8 The seventh circuit diagram of the embodiment of the utility model;
[0031] Figure 9 The eighth circuit diagram of the embodiment of the utility model;
[0032] Figure 10 The ninth circuit diagram of the embodiment of the utility model;
[0033] Figure 11 The tenth circuit diagram of the embodiment of the utility model;
[0034] Figure 12 The measurement schematic view of the embodiment of the utility model.
[0035] The shell 1, the mounting bracket 2, the USB interface 3, the air pressure pump 4, the contact head 5, the analog-digital converter 6. Specific implementation
[0036] The technical solutions in the embodiments of the utility model will be apparently and completely described below with reference to the drawings in the embodiments of the utility model. Apparently, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the utility model.
[0037] In the description of the utility model, it is understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the utility model.
[0038] As Figures 1 to 12 shown,
[0039] The test tool body and the test circuit,
[0040] The test tool body comprises a shell 1 and a mounting bracket 2 for mounting a resistive pressure sensor, the mounting bracket 2 is distributed in a plurality of and annularly in the shell 1, and the mounting bracket 2 is provided with a USB interface 3 connected with the resistive pressure sensor at one end.
[0041] The shell 1 is provided with an air pressure pump 4, and the air pressure pump 4 is connected with a contact head 5 at an output end, the contact head 5 is used for connecting with a pressure interface of the resistive pressure sensor, and is used for applying accurate and adjustable pressure to the sensor, so that the pressure environment of the sensor in actual application is simulated by the air pressure pump 4, and the performance of the sensor is comprehensively verified.
[0042] The side wall of the shell 1 is provided with an analog-to-digital converter 6, the analog-to-digital converter 6 is in communication connection with the resistive pressure sensor, is used for collecting the output signal of the sensor, and transmits the output signal to a computer or a display device.
[0043] The test circuit comprises a power supply +VIN, a transistor SE, a resistor VR, a bias voltage source BIAS, a transistor R1, a transistor R2 and a diode VD, the diode VD adopts a model of 1N4148, and the power supply +VIN adopts a current source chip LM134 to make a 1mA current source
[0044] The pressure difference between the working voltage and the output end voltage is greater than 1V.
[0045] The power supply +VIN is connected with the base of the transistor SE,
[0046] The resistor VR is connected with the base of the transistor SE,
[0047] The bias voltage source BIAS is connected with the base of the transistor SE, and a stable DC bias voltage is provided.
[0048] The transistor R1, the transistor R2 and the transistor VD are connected in parallel.
[0049] The number of the power supply circuit is 10, and one LM134 chip is used for each circuit, and multi-way expansion is realized by copying a single constant current source circuit.
[0050] Working principle: a 1mA current source is made by using a current source chip LM134 of TI company. One chip corresponds to one current source, and 10 chips correspond to 10 current sources. To increase the number of a batch of tests, only the control circuit of a single current source needs to be copied.
[0051] According to the official LM134 constant current source circuit diagram, the supply voltage +VIN can be adjusted according to actual needs, the chip itself is compatible with 0~40V power supply voltage, and the highest voltage of the chip output end can be calculated according to the load impedance input by the rear-end constant current source current, so as to ensure that the working voltage and the output end voltage have a voltage difference of at least 1V or more, so as to ensure that the chip output horizontal current. If the rear-end resistance is 5kΩ, the supply voltage is guaranteed to be 6V or more.
[0052] The constant current source chip LM134 is a negative temperature coefficient, and a positive temperature coefficient device is needed to balance the influence of temperature on the constant current source LM134. The official circuit uses diode 1N457, and the 1N4148 used in the present tooling can perfectly replace it.
[0053] During the design process, two formulas are needed to calculate the resistance value, formula (1) is the temperature drift calculation formula, and formula (2) is the constant current calculation formula. According to the actual required current value, a binary linear equation set is listed, and the values of R1 and R2 are obtained. For example, if the current source I need is 1mA, the equation set is as follows.
[0054]
[0055] Solving the equation set gives R1=134Ω, R2=1345Ω.
[0056] Using the temperature drift calculation formula and the constant current calculation formula to establish a binary linear equation set; solving the equation set according to the target current value, the resistance values of R1 and R2 are obtained,
[0057] Temperature drift calculation formula:
[0058]
[0059] Constant current calculation formula:
[0060]
[0061] Verification test, the current source output current is continuously tested for 12 hours, the standard deviation of the current source is within 100nA, the 1mA accuracy is 0.01%, and it can be used for testing sensors with accuracy of 0.05% and above.
[0062] The above only describes the preferred embodiments of the present application, and does not limit the present application, and those skilled in the art can make usual changes and replacements within the technical scheme of the present application, which should be included in the protection scope of the present application.
Claims
1. A current excitation test fixture for a resistive pressure sensor, characterized by: The test tool body comprises a shell (1) and a mounting bracket (2) for mounting a resistance pressure sensor, the mounting bracket (2) is arranged in the shell (1) in a plurality of and annular distribution, and the mounting bracket (2) is provided with a USB interface (3) connected with the resistance pressure sensor at one end, The shell (1) is provided with an air pressure pump (4) at the top, and the air pressure pump (4) is connected with a contact head (5) at the output end, and the contact head (5) is used for connecting with a pressure interface of the resistance pressure sensor, The side wall of the shell (1) is provided with an analog-to-digital converter (6), and the analog-to-digital converter (6) is connected with the resistance pressure sensor in communication, The test circuit comprises a power supply +VIN, a transistor SE, a resistor VR, a bias voltage source BIAS, a transistor R1, a transistor R2 and a diode VD, the power supply +VIN is connected with the base of the transistor SE, The resistor VR is connected with the base of the transistor SE, The bias voltage source BIAS is connected with the base of the transistor SE, and a stable DC bias voltage is provided, The transistor R1, the transistor R2 and the transistor VD are connected in parallel. The number of power supply circuits is 10, and one LM134 chip is used for each circuit, and multi-way expansion is realized by copying a single constant current source circuit.
2. The current excitation test tool for a resistive pressure sensor according to claim 1, wherein: The model of the diode VD is 1N4148.
3. The current excitation test fixture for a resistive pressure sensor of claim 1, wherein: The power supply +VIN is made of a current source chip LM134 to produce a 1mA current source.
4. The current excitation test fixture for a resistive pressure sensor of claim 1, wherein: The pressure difference between the working voltage and the output end voltage is greater than 1V.
5. The current excitation test fixture for a resistive pressure sensor of claim 1, wherein: