A real-time monitoring resistance change test platform

Abstract

The utility model provides a real -time monitoring resistance change test platform, including cold and hot impact box, reference resistance, constant potential source and temperature -voltage recorder, the FPC board of waiting and examining is placed in the cold and hot impact box, its top has set up and passed the wire hole, reference resistance is outside the cold and hot impact box, and its one end passes through the wire cable and is connected to the one end of NTC resistance on the FPC board of waiting and examining through the wire hole, and the other end is connected to the positive pole of constant potential source, the negative pole of constant potential source passes through the wire cable and is connected to the other end of NTC resistance through the wire hole, the first temperature sampling point of temperature -voltage recorder is pasted on the surface of cold and hot impact box through thermocouple line, and its voltage sampling point is connected in parallel at the both ends of reference resistance, the utility model discloses through reference resistance and temperature -voltage recorder realizes equivalent real -time tracking NTC resistance, reaches the effect that resistance real -time tracking, measurement precision is high and low cost.

Description

Technical Field

[0001] This utility model relates to the field of FPC reliability testing technology, specifically to a test platform for real-time monitoring of resistance changes. Background Technology

[0002] Currently, in the field of temperature sensing, negative temperature coefficient thermistors (NTCs) are widely used in flexible printed circuit board (FPC) designs for automotive electronics, energy storage systems, and other applications due to their wide temperature range, high accuracy, and fast response characteristics. However, the resistance-temperature relationship of NTCs is significantly nonlinear, and their performance is prone to drift or failure under extreme temperature cycling conditions such as thermal shock. Therefore, rigorous environmental testing is required to verify their reliability. While thermal shock test chambers can simulate rapid temperature changes, their function is limited to simulating temperature environments and cannot monitor the dynamic response of NTC resistance in real time. The testing process relies on manual periodic sampling or offline testing using an external dedicated impedance analyzer, which leads to the following drawbacks in existing testing solutions: 1. Lack of real-time capability. Manual measurement intervals are long, making it impossible to capture the resistance jumps that occur during thermal shock transients in a timely manner. Such transient resistance values ​​are the key basis for judging the failure of NTC thermal stress resistance.

[0003] 2. Insufficient accuracy and continuity. Traditional handheld multimeters have relatively large measurement errors, and opening the box for sampling introduces environmental interference, which disrupts the stability of the temperature field and leads to distorted test data; 3. High cost of setting up the test platform. Dedicated impedance analyzers that support real-time sampling over a wide temperature range are expensive and require independent deployment, which occupies additional space and maintenance resources.

[0004] Due to the shortcomings of existing testing platforms, in practical applications, current testing solutions often struggle to balance reliability and cost-effectiveness. They either require significant investment in new equipment and facility expansion, or they must accept the risk of product failure due to incomplete reliability verification data. Therefore, there is an urgent need for a testing platform that can achieve real-time resistance tracking, high measurement accuracy, and low cost. Utility Model Content

[0005] This utility model provides a real-time resistance change monitoring test platform, which is mainly used to solve the problems of lack of real-time performance, insufficient accuracy and continuity, and high test platform construction cost in existing NTC performance verification test schemes, thereby achieving the effect of real-time resistance tracking, high measurement accuracy and low cost.

[0006] This utility model achieves the above objectives through the following technical solutions: A real-time resistance change monitoring test platform includes a thermal shock chamber, a reference resistor, a constant voltage source, and a temperature-voltage recorder. The thermal shock chamber contains an FPC board under test, with a cable routing hole on its top. The reference resistor is externally located within the thermal shock chamber, with one end connected via a cable passing through the cable routing hole to one end of an NTC resistor on the FPC board under test, and the other end connected to the positive terminal of the constant voltage source. The negative terminal of the constant voltage source is connected via a cable passing through the cable routing hole to the other end of the NTC resistor. The first temperature sampling point of the temperature-voltage recorder is attached to the surface of the thermal shock chamber via a thermocouple wire, and its voltage sampling point is connected in parallel across the reference resistor.

[0007] A further embodiment is that the thermal shock chamber is provided with an observation window on its side, and a test rack is provided inside the chamber directly opposite the observation window, on which the FPC board to be tested is placed.

[0008] A further solution is to fill the wire hole with a silicone sealing plug, and the center of the silicone sealing plug has a cable through hole. The diameter of the cable through hole is smaller than the outer diameter of the cable passing through it, forming an interference fit on the surface to achieve airtight sealing.

[0009] A further option is to use a 10kΩ metal film resistor as the reference resistor.

[0010] A further solution includes a temperature compensation circuit, wherein the input of the temperature compensation circuit acquires the temperature value of the reference resistor, and its output is connected in parallel with the reference resistor, for real-time temperature drift compensation of the reference resistor based on the temperature value, thereby controlling the resistance deviation of the reference resistor within ±0.05% over the entire temperature range.

[0011] A further embodiment is that the temperature compensation circuit includes a Pt100 platinum resistance thermometer and an operational amplifier. The Pt100 platinum resistance thermometer is attached to the surface of the reference resistor to acquire the temperature value of the reference resistor in real time and output the temperature value to the first input terminal of the operational amplifier. The second input terminal of the operational amplifier is connected to the reference temperature value to compare the temperature value with the reference temperature value and output a voltage compensation signal based on the comparison result and the temperature-resistance relationship of the metal film resistor.

[0012] A further embodiment is that the temperature-voltage recorder is also provided with a second temperature sampling point, which is attached to the surface of the NTC resistor through the through hole via a thermocouple wire, for monitoring the temperature of the NTC resistor.

[0013] A further embodiment is that the temperature-voltage recorder is used to periodically collect the voltage value across the reference resistor, calculate the real-time resistance value of the NTC resistor based on the voltage value across the reference resistor, and output the NTC resistance response characteristic curve based on the NTC resistor and the temperature values ​​collected at the first and second temperature sampling points.

[0014] Therefore, this utility model has the following beneficial effects: 1. This utility model uses a reference resistor externally placed in the thermal shock chamber to form a voltage divider circuit in series with the NTC resistor on the FPC board under test inside the chamber, and uses a constant voltage source as the power supply. Only the resistance value of the reference resistor needs to be detected to achieve equivalent real-time tracking of the resistance value of the NTC resistor. Compared with the traditional manual timed sampling measurement, it can capture the resistance value jump that occurs during the transient process of thermal shock in a timely manner through real-time monitoring.

[0015] 2. The reference resistor of this utility model adopts a metal film resistor, and by setting a temperature compensation circuit, the resistance deviation of the reference resistor in the whole temperature range is controlled within ±0.05%. Moreover, the reference resistor is separated from the FPC board under test in the test platform, so that the reference resistor can maintain a stable resistance value and suppress the influence of temperature drift under thermal shock environment, thereby improving the measurement accuracy.

[0016] 3. The reference resistor of this utility model is a 10kΩ large resistor connected in series with an NTC resistor. When the resistance of the NTC resistor is extremely low in the high temperature region, the 10kΩ large resistor can limit the circuit current and avoid overload damage to the NTC resistor.

[0017] 4. The real-time resistance change monitoring test platform of this utility model has low construction cost, can make maximum use of existing test equipment and test site to realize real-time tracking of NTC resistance and obtain real-time NTC resistance response characteristics, maximize the existing asset value of the test project, and has high practical application value.

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the real-time resistance change monitoring test platform provided in this embodiment of the utility model.

[0020] Figure 2 This is a perspective view of the thermal shock chamber of the real-time resistance change monitoring test platform provided in this embodiment of the utility model.

[0021] Figure 3 This is a circuit connection diagram of the real-time resistance change monitoring test platform provided in this embodiment of the utility model. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the described embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0023] An embodiment of a test platform for real-time monitoring of resistance changes See Figure 1 The present invention relates to a real-time resistance change monitoring test platform, comprising a thermal shock chamber 10, a reference resistor 20, a constant voltage source 30, and a temperature-voltage recorder 40. The thermal shock chamber 10 contains an FPC board to be tested, with a wire-through hole 11 on its top. The reference resistor 20 is externally mounted on the thermal shock chamber 10, with one end connected to one end of an NTC resistor on the FPC board via a cable passing through the wire-through hole 11, and the other end connected to the positive terminal of the constant voltage source 30. The negative terminal of the constant voltage source 30 is connected to the other end of the NTC resistor via a cable passing through the wire-through hole 11. The first temperature sampling point of the temperature-voltage recorder is attached to the surface of the thermal shock chamber 10 via a thermocouple wire, and its voltage sampling point is connected in parallel across the reference resistor 20.

[0024] Specifically, in this embodiment, the thermal shock chamber 10 adopts a three-compartment structure, including a high-temperature chamber, a low-temperature chamber, and a test chamber, which can provide a temperature shock range of -70℃ to 180℃.

[0025] Specifically, in this embodiment, the cables entering the thermal shock chamber 10 are high-temperature resistant PVC insulated cables.

[0026] Specifically, in this embodiment, the constant voltage source 30 is a DC constant voltage source 30, with an output power supply voltage of 5V±1mV and ripple <0.5mV.

[0027] Specifically, in this embodiment, the voltage sampling channel of the temperature-voltage recorder 40 uses a 24-bit ADC with a sampling rate set to 1kHz.

[0028] Specifically, the real-time resistance change monitoring test platform in this embodiment also includes a monitoring host. The monitoring host is connected to the output terminal of the temperature-voltage recorder 40 to receive test data and determine whether the performance of the NTC resistor meets the requirements based on the test data. It also captures the resistance response characteristics of the NTC resistor under extreme temperature cycling by analyzing the NTC resistance response characteristic curve, and determines whether there are open circuits, short circuits, or characteristic degradation of the NTC resistor in the test platform, so as to generate a test report output.

[0029] The test data includes the real-time resistance value of the NTC resistor, the temperature values ​​collected at the first and second temperature sampling points, the NTC resistance response characteristic curve, and the test period.

[0030] The test report includes data such as NTC resistance-temperature hysteresis curve, step response time, and aging coefficient β value.

[0031] See Figure 2 In this embodiment, the thermal shock chamber 10 is also provided with an observation window 12 on its side, and a test rack 13 is provided in the chamber directly opposite the observation window 12, and the FPC board to be tested is placed on the test rack 13.

[0032] Specifically, in this embodiment, the observation window 12 is made of double-layered tempered glass, and the test rack 13 is equipped with an adjustable spacing slide rail for quick snap-fit ​​fixing of the FPC board.

[0033] In this embodiment, the wire hole 11 is filled with a silicone sealing plug, and the center of the silicone sealing plug has a cable through hole. The diameter of the cable through hole is smaller than the outer diameter of the cable passing through it, and an interference fit is formed on the surface to achieve airtight sealing.

[0034] See Figure 3 In this embodiment, the reference resistor 20 is a metal film resistor with a resistance of 10kΩ.

[0035] Specifically, in this embodiment, the metal film resistor is mounted on an aluminum alloy heat sink to prevent self-heating and temperature drift.

[0036] In this embodiment, a temperature compensation circuit is also included. The input terminal of the temperature compensation circuit collects the temperature value of the reference resistor 20, and its output terminal is connected in parallel with the reference resistor 20. It is used to perform real-time temperature drift compensation on the reference resistor 20 according to the temperature value, and control the resistance deviation of the reference resistor 20 in the whole temperature range within ±0.05%.

[0037] In this embodiment, the temperature compensation circuit includes a Pt100 platinum resistance thermometer and an operational amplifier. The Pt100 platinum resistance thermometer is attached to the surface of the reference resistor 20 and is used to acquire the temperature value of the reference resistor 20 in real time, and output the temperature value to the first input terminal of the operational amplifier. The second input terminal of the operational amplifier is connected to the reference temperature value and is used to compare the temperature value with the reference temperature value, and output a voltage compensation signal according to the comparison result and the temperature-resistance relationship of the metal film resistor.

[0038] Specifically, the temperature compensation circuit in this embodiment also includes a DAC circuit, which outputs a compensation voltage to the reference resistor 20 based on the voltage compensation signal. The voltage output range of the DAC circuit is ±100mV, satisfying the voltage compensation requirements across the entire temperature range of the reference resistor 20.

[0039] In this embodiment, the temperature-voltage recorder is further provided with a second temperature sampling point, which is attached to the surface of the NTC resistor by passing a thermocouple wire through the wire hole 11, and is used to monitor the temperature of the NTC resistor.

[0040] In this embodiment, the temperature-voltage recorder 40 is used to periodically collect the voltage value across the reference resistor 20, calculate the real-time resistance value of the NTC resistor based on the voltage value across the reference resistor 20, and output the NTC resistance response characteristic curve based on the NTC resistor and the temperature values ​​collected at the first and second temperature sampling points.

[0041] Specifically, in this embodiment, the temperature-voltage recorder 40 generates an NTC resistance response characteristic curve by plotting the resistance value of the reference resistor 20 over time and superimposing a dual temperature curve on the curve, and automatically marking the resistance jump point on the NTC resistance response characteristic curve.

[0042] The above embodiments are merely preferred embodiments of this utility model and should not be construed as limiting the scope of protection of this utility model. Any non-substantial changes and substitutions made by those skilled in the art based on this utility model shall fall within the scope of protection claimed by this utility model.

Claims

1. A test platform for real-time monitoring of resistance changes, characterized in that, include: The system comprises a thermal shock chamber, a reference resistor, a constant voltage source, and a temperature-voltage recorder. The thermal shock chamber contains an FPC board under test, with a cable routing hole on its top. The reference resistor is externally located within the thermal shock chamber, with one end connected via a cable passing through the cable routing hole to one end of an NTC resistor on the FPC board under test, and the other end connected to the positive terminal of the constant voltage source. The negative terminal of the constant voltage source is connected via a cable passing through the cable routing hole to the other end of the NTC resistor. The first temperature sampling point of the temperature-voltage recorder is attached to the surface of the thermal shock chamber via a thermocouple wire, and its voltage sampling point is connected in parallel across the reference resistor.

2. The real-time resistance change monitoring test platform according to claim 1, characterized in that: The thermal shock chamber is also provided with an observation window on its side, and a test rack is provided inside the chamber directly opposite the observation window, on which the FPC board to be tested is placed.

3. The real-time resistance change monitoring test platform according to claim 2, characterized in that: The cable passage hole is filled with a silicone sealing plug, and the center of the silicone sealing plug has a cable through hole. The diameter of the cable through hole is smaller than the outer diameter of the cable passing through it, forming an interference fit on the surface to achieve airtight sealing.

4. The real-time resistance change monitoring test platform according to claim 1, characterized in that: The reference resistor is a 10kΩ metal film resistor.

5. The real-time resistance change monitoring test platform according to claim 4, characterized in that: It also includes a temperature compensation circuit, the input of which acquires the temperature value of the reference resistor, and its output is connected in parallel with the reference resistor. It is used to perform real-time temperature drift compensation on the reference resistor based on the temperature value, and control the resistance deviation of the reference resistor within ±0.05% over the entire temperature range.

6. The real-time resistance change monitoring test platform according to claim 5, characterized in that: The temperature compensation circuit includes a Pt100 platinum resistance thermometer and an operational amplifier. The Pt100 platinum resistance thermometer is attached to the surface of the reference resistor and is used to acquire the temperature value of the reference resistor in real time and output the temperature value to the first input terminal of the operational amplifier. The second input terminal of the operational amplifier is connected to the reference temperature value and is used to compare the temperature value with the reference temperature value, and output a voltage compensation signal according to the comparison result and the temperature-resistance relationship of the metal film resistor.

7. The real-time resistance change monitoring test platform according to claim 1, characterized in that: The temperature-voltage recorder is also provided with a second temperature sampling point, which is attached to the surface of the NTC resistor through the through hole via a thermocouple wire, and is used to monitor the temperature of the NTC resistor.

8. The real-time resistance change monitoring test platform according to claim 7, characterized in that: The temperature-voltage recorder is used to periodically collect the voltage value across the reference resistor, calculate the real-time resistance value of the NTC resistor based on the voltage value across the reference resistor, and output the NTC resistance response characteristic curve based on the NTC resistor and the temperature values ​​collected at the first and second temperature sampling points.

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