Shunt resistor with temperature detection function

Abstract

The invention provides a shunt resistor with a temperature detection function, which comprises a first electrode, a second electrode, an intermediate resistor body and a circuit board acquisition device, and the intermediate resistor body is positioned between the first electrode and the second electrode. The circuit board acquisition device comprises a substrate, a sampling output connector, a temperature acquisition module and a voltage acquisition module. The substrate is provided with a contact surface and an observation surface, the contact surface faces the middle resistor body, a spacing gap exists between the contact surface and the middle resistor body, and the sampling output connector is arranged on the observation surface. And two bonding pads are arranged on the contact surface and correspond to the first electrode and the second electrode respectively. Two ends of the middle resistor body are respectively provided with a thermal insulation wall, and ventilation gaps are formed between the thermal insulation walls and the contact surfaces. According to the shunt resistor, the temperature of the shunt resistor can be acquired in real time, and the resistance values of a product at different temperatures are compensated, so that the measurement precision is improved; and meanwhile, the flowing range of molten welding fluid can be controlled during welding, and stable and firm welding is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of shunt resistors, and in particular to a shunt resistor with a temperature detection function. Background Art

[0002] In broadband power meters and power analyzers, shunt resistors are the main sensors for current measurement. Based on Ohm's law, they convert current signals into voltage signals within a certain range. During the use of shunt resistors, due to the material properties, current passing through the shunt resistors will cause them to heat up, which in turn causes changes in resistance. However, due to the constant temperature changes, the impact of temperature changes on resistance has often been ignored in past use, and the resistance of the shunt resistors has been set to a fixed value by default. This has resulted in a decrease in the measurement accuracy of the shunt resistors during use.

[0003] At the same time, when the existing collection device and the diverter body are subjected to high-temperature welding, the molten welding liquid easily penetrates into the gap between the parts, which easily causes a short circuit between the collection device and the diverter body.

[0004] Therefore, how to design a shunt resistor with temperature detection function so that it can collect the temperature of the shunt resistor in real time and compensate for the resistance of the product at different temperatures to improve the measurement accuracy; at the same time, it can control the flow range of molten solder during welding to prevent short circuit. This is a technical problem that technicians in this field need to solve. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a shunt resistor with a temperature detection function, so that the temperature of the shunt resistor can be collected in real time, and the resistance of the product at different temperatures can be compensated to improve the measurement accuracy; at the same time, the flow range of the molten solder can be controlled during welding to prevent short circuits.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] A shunt resistor with a temperature detection function, comprising: a first electrode, a second electrode, an intermediate resistor and a circuit board acquisition device, wherein the intermediate resistor is located between the first electrode and the second electrode;

[0008] The first electrode, the second electrode and the intermediate resistor together form a bare chip body, and the circuit board acquisition device is arranged on the bare chip body; the circuit board acquisition device includes: a substrate, a sampling output connector, a temperature acquisition module and a voltage acquisition module;

[0009] The substrate is provided with a contact surface and an observation surface, the contact surface faces the intermediate resistor, and there is a space between the contact surface and the intermediate resistor; the observation surface is away from the intermediate resistor, and the sampling output connector is provided on the observation surface;

[0010] Two pads are arranged on the contact surface, the two pads correspond to the first electrode and the second electrode respectively, and the substrate is connected to the first electrode and the second electrode through the pads;

[0011] The thickness of the first electrode and the second electrode is H 1 , the distance of the space gap is H 2 , H 1 >H2; The two ends of the intermediate resistor are respectively provided with a thermal insulation wall, and the thickness of the thermal insulation wall is H 3 , H 3 <H 2 , an air-permeable gap is formed between the thermal insulation wall and the contact surface.

[0012] In one embodiment, a plurality of welding blocks are disposed on each of the welding pads, and the plurality of welding blocks are arranged in a matrix manner, and a blank gap is formed between two adjacent welding blocks.

[0013] In one embodiment, the welding block is made of solder.

[0014] In one embodiment, the temperature acquisition module is disposed on the substrate, and the temperature acquisition module includes an NTC temperature sensor and a temperature sampling wire, and the NTC temperature sensor is electrically connected to the sampling output connector through the temperature sampling wire;

[0015] The voltage acquisition module includes a voltage sampling line, and the sampling output connector and the pad are electrically connected through the voltage sampling line.

[0016] In one embodiment, a label is provided on the contact surface of the substrate.

[0017] In one embodiment, H 2 =0.25H 1 ~0.4H 1 .

[0018] In one embodiment, the first electrode and the second electrode are both provided with mounting holes, and the two mounting holes are symmetrically arranged with the middle resistor as the center.

[0019] In one embodiment, the first electrode and the second electrode are both made of copper.

[0020] In summary, the shunt resistor with temperature detection function of the present invention can collect the temperature of the shunt resistor in real time and compensate for the resistance of the product at different temperatures, thereby improving the measurement accuracy; at the same time, it can control the flow range of the molten solder during welding to prevent short circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 It is a plan view of a shunt resistor with a temperature detection function of the present invention;

[0023] Figure 2 for Figure 1 A side view of a shunt resistor with temperature sensing function is shown;

[0024] Figure 3 A three-dimensional diagram of a bare chip body of a shunt resistor having a temperature detection function;

[0025] Figure 4 A plan view of a bare chip body of a shunt resistor having a temperature detection function;

[0026] Figure 5 for Figure 1 A plan view of the circuit board acquisition device shown (I);

[0027] Figure 6 for Figure 1 The schematic plan view of the circuit board acquisition device shown (II);

[0028] Figure 7 for Figure 1 A partial cross-sectional view of a shunt resistor with a temperature detection function shown;

[0029] Figure 8 This is the temperature compensation curve fitted according to the test values. DETAILED DESCRIPTION

[0030] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.

[0031] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0033] The present invention provides a shunt resistor 10 with a temperature detection function, such as Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, it includes: a first electrode 100, a second electrode 200, an intermediate resistor 300 and a circuit board acquisition device 400. The intermediate resistor 300 is located between the first electrode 100 and the second electrode 200. The nominal resistance of the shunt resistor 10 is determined by the size and size of the intermediate resistor 300. The first electrode 100, the second electrode 200 and the intermediate resistor 300 together form a bare chip body, and the circuit board acquisition device 400 is arranged on the bare chip body.

[0034] like Figure 5 and Figure 6 As shown, the circuit board acquisition device 400 includes: a substrate 410, a sampling output connector 420, a temperature acquisition module 430 and a voltage acquisition module 440. The substrate 410 is provided with a contact surface 411 and an observation surface 412, the contact surface 411 faces the intermediate resistor 300, and there is a space 401 between the contact surface 411 and the intermediate resistor 300. The observation surface 412 is away from the intermediate resistor 300, and the sampling output connector 420 is arranged on the observation surface 412. Two pads 413 are arranged on the contact surface 411, and the two pads 413 correspond to the first electrode 100 and the second electrode 200 respectively. The substrate 410 is connected to the first electrode 100 and the second electrode 200 through the pads 413.

[0035] In this embodiment, if Figure 5 As shown, the temperature acquisition module 430 is disposed on the substrate 410 , and the temperature acquisition module 430 includes an NTC temperature sensor 431 and a temperature sampling wire 432 . The NTC temperature sensor 431 is electrically connected to the sampling output connector 420 via the temperature sampling wire 432 .

[0036] like Figure 6 As shown, the voltage acquisition module 440 includes a voltage sampling line 441 , and the sampling output connector 420 and the pad 413 are electrically connected through the voltage sampling line 441 .

[0037] The working principle of the shunt resistor 10 with temperature detection function of the present invention is as follows:

[0038] When in use, first, the circuit board acquisition device 400 is welded to the bare chip body, and the sampling output connector 420 is electrically connected to the external reading device; then, the first electrode 100 and the second electrode 200 are connected to the positive and negative poles of the power supply respectively, and the current passes through the first electrode 100, the intermediate resistor 300 and the second electrode 200 in sequence. Then, the resistance value of the NTC temperature sensor 431 is read by the external reading device, so as to obtain the surface temperature of the intermediate resistor 300 at this time, and then obtain the resistance value of the shunt resistor 10 at this time. At the same time, using the voltage acquisition module 440 of the circuit board acquisition device 400, the external reading device can read the voltage at both ends of the bare chip body, and use the formula to calculate the current of the shunt resistor 10 at this time.

[0039] like Figure 8 As shown, the horizontal axis represents temperature, and the vertical axis represents the resistance ratio (the resistance measured at each temperature divided by the resistance at the reference temperature). Using the formula: R=A*T*T+B*T+C (R is resistance, T is temperature, A, B, C are calibration coefficients), the resistance of the shunt is calibrated by testing at different temperatures and currents, and then the temperature compensation curve is obtained based on the test values.

[0040] Compared with traditional shunts, the shunt resistor 10 of the present invention can obtain the temperature of the intermediate resistor 300 in real time through the NTC temperature sensor 431, and then match the temperature compensation curve to obtain the resistance value of the intermediate resistor 300 at different temperatures, so that the circuit test accuracy of the shunt resistor 10 at different temperatures is higher and the measurement is more accurate.

[0041] In this embodiment, if Figure 5 As shown, a label 414 is provided on the contact surface 411 of the substrate 410. During production, the shunt resistor 10 is calibrated and tested to obtain a temperature compensation curve, and then the nominal value of the shunt resistor 10 is measured. The obtained nominal value and temperature compensation curve are marked on the label 414 in the form of a QR code by silk-screen printing, laser marking or other means, so as to achieve complete and real-time recording of information, thereby more accurately conveying it to the user end of the product.

[0042] Furthermore, the present invention also solves the technical problem of welding the circuit board acquisition device 400 to the bare chip body. In the conventional electrical connection welding method, solder is usually applied on the first electrode 100 and the second electrode 200 of the bare chip body, and then the solder is first heated to a molten state, and then the circuit board acquisition device 400 is pressed on the molten solder; of course, the circuit board acquisition device 400 can also be placed on the solder first, and then the shunt resistor 10 is heated at a high temperature so that it is solidified after being melted at a high temperature, thereby achieving welding. However, it is found in the actual production process that the above conventional welding has the following problems: Since the intermediate resistor 300 of the existing bare chip body is flush with the first electrode 100 and the second electrode 200, when the circuit board acquisition device 400 is on the bare chip body, the gap between the two is small, and the gap will form a "tin creeping" capillary effect, so that the molten solder penetrates into the gap (equivalent to the molten solder forming a "conductive connection bridge" between the first electrode 100 and the second electrode 200). In this case, the solder that penetrates into the gap will adhere to the intermediate resistor 300 and even connect the first electrode 100 and the second electrode 200, resulting in a short circuit in the bare chip body.

[0043] In order to solve the above technical problems, the shunt resistor 10 of the present invention is specially designed, specifically:

[0044] On the one hand, if Figure 7 As shown, there is a space 401 between the contact surface 411 of the substrate 410 and the intermediate resistor 300. Preferably, the thickness of the first electrode 100 and the second electrode 200 are both H 1 , the distance between the gap 401 is H 2 , H 1 >H 2 , and H 2 =0.25H 1 ~0.4H 1 For example, H 1 =10mm, then H 2 =2.5mm~4mm. After designing the spacer gap 401, the thickness of the intermediate resistor 300 will be significantly smaller than the thickness of the first electrode 100 and the second electrode 200 (the difference is H 2 ). In this way, the existence of the spacer gap 401 causes the gap between the circuit board acquisition device 400 and the bare chip body to be interrupted, so that there is no "tin creeping" capillary effect. When part of the molten solder overflows, the overflowed molten solder will fall into the spacer gap 401. In this way, the overflowed molten solder of the two pads 413 cannot be connected to each other, that is, no "conductive connection bridge" will be formed between the two, and no short circuit will occur;

[0045] On the other hand, Figure 6As shown, two pads 413 are provided on the contact surface 411, and the two pads 413 correspond to the first electrode 100 and the second electrode 200 respectively. Preferably, each pad 413 is provided with a plurality of welding blocks 4131, and the plurality of welding blocks 4131 are arranged in a matrix manner, and a blank gap is formed between two adjacent welding blocks 4131. The welding blocks 4131 are made of solder;

[0046] On the other hand, Figure 3 As shown, a thermal insulation wall 310 is provided at both ends of the middle resistor 300, and the thickness of the thermal insulation wall 310 is H 3 , H 3 <H 2 Thus, a breathable gap 301 (such as Figure 2 As shown, in this embodiment, the insulation wall 310 and the middle resistor 300 are stamped into an integral body of the same type of alloy material; it can be understood that the setting of the insulation wall 310 does not completely seal the internal space gap 401. The main purpose of the insulation wall 310 is to ensure the constant temperature inside the space gap 401 and prevent the heat generated by the middle resistor 300 from being affected by the outside and escaping too quickly. Therefore, the NTC temperature sensor 431 can more accurately collect the temperature of the middle resistor 300 and improve the accuracy of the reading; in addition, the insulation wall 310 and the contact surface 411 are The air-permeable gap 301 is formed, and the heat generated by the middle resistor 300 can be appropriately dissipated outward through the air-permeable gap 301, so that the high heat will not be suffocated in the space 401 and unable to be dissipated, thereby causing damage to related components, which will not have a substantial impact on the accuracy of the readings; the air-permeable gap 301 is formed between the thermal insulation wall 310 and the contact surface 411, and it is precisely the setting of this air-permeable gap 301 that prevents the molten welding block 4131 from "climbing" through the thermal insulation wall 310 to the contact surface 411 of the middle resistor 300 or the substrate 410, thereby preventing a short circuit.

[0047] The welding process of the circuit board acquisition device 400 is as follows: the welding pad 413 is pre-arranged with welding blocks 4131 arranged in a matrix manner (such as Figure 6 As shown in the figure, a blank gap is formed between adjacent welding blocks 4131; then, the staff places the circuit board acquisition device 400 on the bare chip body so that the two welding pads 413 correspond to the first electrode 100 and the second electrode 200 respectively; then, the shunt resistor 10 is heated at a high temperature to melt the welding block 4131; finally, the shunt resistor 10 is cooled, and the welding block 4131 solidifies back to a solid state during the cooling period, thereby achieving stable welding;

[0048] During this process, the welding block 4131 becomes molten solder liquid at high temperature, and the solder liquid will penetrate all around. Since there is a blank gap on the pad 413, the molten welding block 4131 will first fill the blank gap, that is, the blank gap provides a receiving space for the molten solder liquid, thereby reducing the overflow of the molten solder liquid. At the same time, the blank gap is connected to the outside world, so that when the molten solder liquid penetrates all around, the excess air can escape in time, thereby effectively preventing the void problem in the welding process, reducing the welding bubble rate, and ensuring the firm connection between the pad 413 and the first electrode 100 and the second electrode 200, as well as good conductive performance. It should be further emphasized that, from the above, it can be seen that the setting of the thermal insulation wall 310 does not completely seal the internal space gap 401. A breathable gap 301 is formed between the thermal insulation wall 310 and the contact surface 411. It is precisely the setting of this breathable gap 301 that prevents the molten welding block 4131 from "climbing" through the thermal insulation wall 310 to the contact surface 411 of the intermediate resistor 300 or the substrate 410, thereby preventing a short circuit.

[0049] From the above, it can be seen that the setting of the space gap 401 has the following benefits: first, it blocks the continuity of the gap between the circuit board acquisition device 400 and the bare chip body, so that it no longer has the "tin creeping" capillary effect, so that the seeping molten solder will not spread along the gap to form a "conductive connection bridge"; second, the excess molten solder will drip into the space gap 401, and after it cools and solidifies, the staff can easily remove the solder in the space gap 401. If there is no space gap 401, the solder in the gap will be difficult to remove.

[0050] In this embodiment, if Figure 4 As shown, the first electrode 100 and the second electrode 200 are both provided with mounting holes 110, and the two mounting holes 110 are symmetrically arranged with the middle resistor 300 as the center. The mounting holes 110 are arranged to facilitate the electrical connection and installation of the bare chip body. Preferably, the first electrode 100 and the second electrode 200 are both made of copper. The copper material has a small resistance, so it can have good electrical conductivity and reduce its own heating phenomenon.

[0051] In summary, the shunt resistor 10 with temperature detection function of the present invention can collect the temperature of the shunt resistor 10 in real time, and compensate for the resistance of the product at different temperatures, thereby improving the measurement accuracy; at the same time, it can control the flow range of the molten solder during welding to achieve stable and firm welding.

[0052] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A shunt resistor with temperature detection function, characterized in that: include: A first electrode, a second electrode, an intermediate resistor and a circuit board acquisition device, wherein the intermediate resistor is located between the first electrode and the second electrode; The first electrode, the second electrode and the intermediate resistor together form a bare chip body, and the circuit board acquisition device is arranged on the bare chip body; the circuit board acquisition device includes: a substrate, a sampling output connector, a temperature acquisition module and a voltage acquisition module; The substrate is provided with a contact surface and an observation surface, the contact surface faces the intermediate resistor, and there is a space between the contact surface and the intermediate resistor; the observation surface is away from the intermediate resistor, and the sampling output connector is provided on the observation surface; Two pads are arranged on the contact surface, the two pads correspond to the first electrode and the second electrode respectively, and the substrate is connected to the first electrode and the second electrode through the pads; The thickness of the first electrode and the second electrode is H1, the distance of the space gap is H2, H1>H2; thermal insulation walls are respectively provided at both ends of the intermediate resistor, the thickness of the thermal insulation wall is H3, H3<H2, and an air-permeable gap is formed between the thermal insulation wall and the contact surface.

2. The shunt resistor with temperature detection function according to claim 1, characterized in that: A plurality of welding blocks are arranged on each of the welding pads. The plurality of welding blocks are arranged in a matrix manner, and a blank gap is formed between two adjacent welding blocks.

3. The shunt resistor with temperature detection function according to claim 2, characterized in that: The welding block is made of solder.

4. The shunt resistor with temperature detection function according to claim 1, characterized in that: The temperature acquisition module is arranged on the substrate, and the temperature acquisition module includes an NTC temperature sensor and a temperature sampling wire, and the NTC temperature sensor is electrically connected to the sampling output connector through the temperature sampling wire; The voltage acquisition module includes a voltage sampling line, and the sampling output connector and the pad are electrically connected through the voltage sampling line.

5. The shunt resistor with temperature detection function according to claim 1, characterized in that: A label is arranged on the contact surface of the substrate.

6. The shunt resistor with temperature detection function according to claim 1, characterized in that: H2=0.25H1~0.4H1.

7. The shunt resistor with temperature detection function according to claim 1, characterized in that: The first electrode and the second electrode are both provided with mounting holes, and the two mounting holes are symmetrically arranged with the middle resistor as the center.

8. The shunt resistor with temperature detection function according to claim 1, characterized in that: The first electrode and the second electrode are both made of copper.

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