CN218676623U

CN218676623U - Chip resistor

Info

Publication number: CN218676623U
Application number: CN202121868770.XU
Authority: CN
Inventors: 杨漫雪; 唐彬
Original assignee: Nanjing Sart Science and Technology Development Co Ltd
Current assignee: Nanjing Sart Science and Technology Development Co Ltd
Priority date: 2021-08-11
Filing date: 2021-08-11
Publication date: 2023-03-21
Anticipated expiration: 2031-08-11

Abstract

The utility model discloses a chip resistor, which comprises an intermediate resistor, resistor electrodes connected with two ends of the intermediate resistor, and a bottom electrode connected below the resistor electrodes; the heat dissipation assembly and the side electrodes cover the upper surfaces of the middle resistor and the resistor electrodes; the heat dissipation assembly is also provided with an end cap electrode, wherein the end cap electrode comprises a lower end electrode positioned below the bottom electrode, an upper end electrode positioned above the heat dissipation assembly and an outer side electrode positioned on the outer side surface of the bottom electrode; the length of the upper end electrode is smaller than that of the lower end electrode, so that the outer surface of the radiating assembly is prevented from being shielded too much, and the radiating capacity of the radiating assembly is improved. The outer surface of the side electrode is attached to the inner side of the outer side electrode, and the side electrode is sequentially attached to the bottom electrode, the resistance electrode and the heat dissipation assembly from bottom to top, so that the heat dissipation capability of the whole heating part is further improved. Therefore, the resistance of the resistor is less affected by the heat.

Description

Chip resistor

Technical Field

The utility model belongs to the technical field of resistance, specifically be a chip resistor.

Background

The accurate sampling resistor is indispensable electronic components in the circuit, and along with the development of lithium cell and brushless motor technique, the effect of sampling resistor is more and more important, and the effect of sampling resistor is when the electric current through sampling resistor changes, and the voltage at sampling resistor both ends changes promptly, feeds back to IC to discern corresponding signal, the precision of resistance value is higher, and is more accurate to the voltage signal of feedback, and the electric current of output is more stable. However, in the specific use of the precision sampling resistor, the temperature of the precision sampling resistor rises due to heat generated after the precision sampling resistor is electrified, and the resistance value of the resistor is directly changed due to the temperature rise. In the prior art, the precision sampling resistor has poor heat dissipation performance, and cannot dissipate heat in time, so that errors occur between a set resistance value and an actual resistance value, and the sampling precision is reduced.

Therefore, a new technical solution is needed to solve the above technical problems.

SUMMERY OF THE UTILITY MODEL

In order to overcome the deficiency that exists among the prior art, the utility model provides a new chip resistor can improve the heat-sinking capability of resistance, and the resistance that makes resistance receives the influence of generating heat is less.

A chip resistor comprises a middle resistor, resistor electrodes connected to two ends of the middle resistor, and a bottom electrode connected below the resistor electrodes; the heat dissipation assembly and the side electrodes cover the upper surfaces of the middle resistor and the resistor electrodes; the heat dissipation assembly is also provided with an end cap electrode, wherein the end cap electrode comprises a lower end electrode positioned below the bottom electrode, an upper end electrode positioned above the heat dissipation assembly and an outer side electrode positioned on the outer side surface of the bottom electrode; the length of the upper end electrode is smaller than that of the lower end electrode; the outer surface of the side electrode is attached to the inner side of the outer electrode, and the side electrode is sequentially attached to the bottom electrode, the resistance electrode and the radiating assembly from bottom to top.

Has the advantages that: the utility model provides an among the chip resistor, owing to need dispel the heat through radiator unit to resistance and electrode part (circular telegram produced thermal part promptly), the event sets up the length of upper end electrode for being less than the length of lower extreme electrode. The lower electrode is not short enough because it needs to be welded on the circuit board as a support, and the upper electrode can be set short to avoid shielding too much outer surface of the heat radiation component, thereby improving the heat radiation capability of the heat radiation component. Meanwhile, the side electrode is arranged and can transmit the heat of the bottom electrode and the resistance electrode to the heat dissipation assembly at the same time, so that the heat of the bottom electrode which is not directly released from the heat dissipation assembly can be rapidly transmitted to the heat dissipation assembly, and the heat dissipation capacity of the whole heating part is further improved. Therefore, the resistance of the resistor is less affected by heat.

Drawings

Fig. 1 is a schematic diagram of a resistor structure of a chip resistor according to the present invention;

fig. 2 is a schematic cross-sectional structure diagram of the chip resistor of the present invention;

fig. 3 is a schematic diagram of a current path of the middle resistor according to the present invention.

Detailed Description

Referring to fig. 1 and 2, the invention discloses a chip resistor, which includes a middle resistor 1, resistor electrodes 10 connected to two ends of the middle resistor 1, a bottom electrode 6 connected to the lower portion of the resistor electrodes, a protective layer 4, a heat dissipation assembly covering the upper surfaces of the middle resistor 1 and the resistor electrodes 10, and side electrodes 7; the protective layer 4 covers the lower surface of the intermediate resistor 1. The heat dissipation assembly is also provided with an end cap electrode, wherein the end cap electrode comprises a lower end electrode 8 positioned below the bottom electrode 6, an upper end electrode 11 positioned above the heat dissipation assembly and an outer side electrode 9 positioned on the outer side surface of the bottom electrode; the length of the upper end electrode 11 is less than that of the lower end electrode 8; the outer surface of the side electrode 7 is attached to the inner side of the outer electrode 9, and the side electrode 7 is sequentially attached to the bottom electrode 6, the resistance electrode 10 and the heat dissipation assembly from bottom to top. The heat dissipation assembly comprises an insulating heat conduction layer 2 covering the middle resistor 1 and the resistor electrode 10 and a support plate 3 covering the insulating heat conduction layer 2. The material of the carrier plate 3 is preferably ceramic. The insulating heat conduction layer 2 is made of heat conduction materials with the thickness of 10 microns and the heat conduction coefficient of more than 0.5W/m.K. The protective layer 4 is an epoxy resin layer or a silica gel layer.

In the present embodiment, since the upper electrode 11 covers the carrier plate 3, in order to avoid shielding the outer surface of the carrier plate 3 excessively, the end cap electrode is set to be asymmetric, that is, the length of the upper electrode 11 is smaller than that of the lower electrode 8, so that the shielding of the carrier plate 3 by the upper electrode 11 is reduced without affecting the soldering capability of the lower electrode 8, and thus the heat absorbed by the carrier plate 3 can be dissipated more quickly.

In contrast, another improvement of the present embodiment over the prior art is that the internal electrode 5 is disposed inside the resistive electrode 10, the internal electrode 5 is connected in parallel with the resistive electrode 10, and the resistivity of the internal electrode 5 is lower than that of the resistive electrode 10, for example, the internal electrode 5 is a copper electrode, a silver electrode, an aluminum electrode, or a gold electrode. The length of the internal electrode 5 is equivalent to the width of the resistance electrode 10, and both ends of the internal electrode 5 are flush with both long-side edges of the resistance electrode 10. Meanwhile, it is preferable that the position of the internal electrode 5 is set at an intermediate position in the width direction of the resistance electrode 10. The resistivity of the position of the resistance electrode 10 is reduced by connecting the inner electrode 5 and the resistance electrode 10 in parallel. As shown in fig. 3, the current flow direction in this embodiment may approximately result in an integrated resistance R =2r1+2r2+2r3+ r0; wherein R0 is the resistance of the middle resistor 1, R1 is the resistance of the end electrode 5, R2 is the resistance of the bottom electrode 8, and R3 is the parallel resistance of the inner electrode 5 and the resistance alloy 10; the R3 internal electrode is made of copper, and the resistivity at 20 ℃ is 0.0172 omega.

As a comparative example, when the internal electrode 5 was not provided, that is, only the resistance value of the resistance alloy 10 was set, the resistance value of the resistance alloy 10 was set to R4. Comparing the two results, R1 and R2 are both low resistance copper electrodes, the resistance is relatively small, and the remaining resistance R4 and R3 are compared, wherein the resistance at 20 ℃ is 0.43 omega.m, which is explained by the R4 resistance electrode being manganin; the resistivity of the manganin is 25 times that of the copper, R4=25 rho L/(1.6 rho L/d) =15.6 rho L/d, the R inner electrode = rho L/(0.2 rho d) =5 rho L/d, R3=3.78 rho L/d can be obtained, and the resistance R3 after parallel connection is about 0.24 times that of R4, so that the resistance of the resistance electrode area is greatly reduced, and the measurement accuracy of the resistance can be improved.

In contrast, in the comparative example, if the internal electrode 5 is not provided, only the larger resistance value of the resistance alloy 10 is in the overall resistance as can be seen from the above comparison. The resistance of the resistance electrode 10 is brought into the overall resistance value, so that the difference exists between the measured resistance value and the resistance value welded to the PCB board by the actual user, and the difference is particularly prominent when the proportion of the resistance value section of the low resistance is large, so that the yield loss is reduced on one hand, and the resistance value precision of the user is increased on the other hand. Therefore, the above-described technical problem can be solved by connecting the internal electrode 5 and the resistance alloy 10 in parallel.

Claims

1. A chip resistor, characterized in that: comprises a middle resistor (1), resistor electrodes (10) connected with two ends of the middle resistor (1), and a bottom electrode (6) connected below the resistor electrodes; the heat dissipation assembly and the side electrode (7) cover the upper surfaces of the middle resistor and the resistor electrode; the heat dissipation assembly is also provided with an end cap electrode, wherein the end cap electrode comprises a lower end electrode (8) positioned below the bottom electrode (6), an upper end electrode (11) positioned above the heat dissipation assembly and an outer side electrode (9) positioned on the outer side surface of the bottom electrode; the length of the upper end electrode (11) is less than that of the lower end electrode (8); the outer surface of the side electrode (7) is attached to the inner side of the outer electrode (9), and the side electrode (7) is sequentially attached to the bottom electrode (6), the resistance electrode (10) and the radiating assembly from bottom to top.

2. A chip resistor according to claim 1, wherein: the radiating assembly comprises an insulating heat conduction layer (2) covering the middle resistor (1) and the resistor electrode (10) and a carrier plate (3) covering the insulating heat conduction layer.

3. A chip resistor according to claim 1, wherein: an inner electrode is arranged in the resistance electrode and is connected with the resistance electrode in parallel; the resistivity of the inner electrode is lower than that of the resistive electrode.

4. A chip resistor according to claim 1 or 2, wherein: the material of the carrier plate is ceramic.

5. A chip resistor according to claim 4, wherein: the length of the internal electrode is equivalent to the width of the resistance electrode, and the two ends of the internal electrode are flush with the two long edges of the resistance electrode.

6. A chip resistor according to claim 5, wherein: the inner electrode is a copper electrode, a silver electrode, an aluminum electrode or a gold electrode.

7. A chip resistor according to claim 6, wherein: the position of the inner electrode is set at the middle position of the resistance electrode in the width direction.

8. A chip resistor according to claim 7, wherein: the insulating heat conduction layer (2) is made of heat conduction materials with the thickness of 10 microns and the heat conduction coefficient of more than 0.5W/m.K.

9. A chip resistor according to claim 8, wherein: the resistor further comprises a protective layer (4), and the protective layer (4) covers the lower surface of the middle resistor.

10. A chip resistor according to claim 9, wherein: the protective layer is an epoxy resin layer or a silica gel layer.