Small-size magnetic shielding inductor

Abstract

The small-size magnetic shielding inductor comprises a packaging layer, a magnetic core framework, a coil body and electrodes, the magnetic core framework is in an H shape, the coil body is wound in the middle of the magnetic core framework, two leading-out ends are electrically connected with the electrodes respectively, and the two electrodes are arranged at the top ends of supporting legs on the two sides of the magnetic core framework respectively. And the coil main body and the magnetic core framework are wrapped with a packaging layer to form a closed magnetic shielding loop. By changing the packaging structure, a better magnetic shielding effect is achieved, leakage flux interference of a product to surrounding adjacent devices and a lower layer circuit is avoided, and the inductance value of the product is effectively improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of inductors, and particularly relates to a small-sized magnetic shielding inductor. Background Art

[0002] At present, the electronics industry is upgrading very fast, product functions are becoming more and more powerful, electronic circuit layouts are complex, and electromagnetic interference (EMI) and electromagnetic compatibility problems trouble many customers. The main electronic product circuit consists of resistors, capacitors, inductors, transformers, active devices and wires. When there is voltage in the circuit, an electric field will be generated around all charged components. When there is current flowing through the circuit, a magnetic field exists around all current-carrying conductors. As long as there is an electric field or magnetic field in the electronic circuit, electromagnetic interference will be generated. In high-speed P32 and system designs, high-frequency signal lines, pins of integrated circuits, various connectors, etc. may all become radiation interference sources with antenna characteristics, which can emit electromagnetic waves and affect the normal operation of other systems or other subsystems within this system.

[0003] For example, in the structure of a conventional wire-wound chip inductor, as Figure 1 shown, it includes UV encapsulation glue A, magnetic core skeleton B, coil body C, and electrodes D. The lower part of the coil body C is surrounded by UV glue A. This inductor is designed as an open magnetic circuit structure and cannot play a magnetic shielding role.

[0004] An electronic product contains hundreds or thousands of inductor components inside. Due to the action of the electromagnetic field, mutual interference will occur between adjacent components. In order to reduce interference, inductor components need to be continuously optimized at the beginning of the design. The basic optimization schemes are material selection and structure design.

[0005] In order to minimize the product size as much as possible and reduce the electromagnetic interference of the magnetic leakage of inductor components to adjacent components, the existing methods are: 1. Increasing the magnetic permeability of the inductor skeleton structure to reduce magnetic leakage, which puts higher requirements on materials and processes and also has a higher cost; 2. Increasing the relative distance between components will result in a decrease in board-level packaging density; 3. Increasing the number of turns of winding, which will affect other characteristics of the inductor product and bring higher losses and heat generation. Summary of the Utility Model

[0006] The purpose of the utility model is to provide a small-sized magnetic shielding inductor, which can play a magnetic shielding role by optimizing the inductor structure on the premise of manufacturing a smaller product size, without sacrificing the electrical properties of the product and without increasing additional costs, and is more conducive to magnetic shielding in the use direction with higher shielding requirements.

[0007] The technical solution adopted by the present utility model is a small-sized magnetic shielding inductor, which includes a packaging layer, a magnetic core skeleton, a coil body and electrodes. The magnetic core skeleton is in an H shape. The coil body is wound around the middle of the magnetic core skeleton, and two lead-out ends are electrically connected to the electrodes respectively. The two electrodes are respectively arranged at the tops of the legs on both sides of the magnetic core skeleton. The coil body and the outer side of the magnetic core skeleton are wrapped with a packaging layer to form a closed magnetic shielding loop.

[0008] Preferably, the above-mentioned packaging layer includes a first packaging layer that wraps around the outer periphery and below of the coil body and the magnetic core skeleton, and a second packaging layer that covers the upper part of the coil body and the magnetic core skeleton. The first packaging layer and the second packaging layer are connected into an integral structure.

[0009] Preferably, the material of the above-mentioned magnetic core skeleton is one of ceramic body, ferrite, iron-silicon-chromium, iron-silicon-aluminum or iron-nickel alloy.

[0010] Preferably, the above-mentioned coil body includes enameled copper wire, which is directly wound on the magnetic core skeleton and is electrically connected to the electrodes through welding.

[0011] Preferably, the above-mentioned electrodes cover a silver layer, a nickel layer and a tin layer in sequence from the inside to the outside.

[0012] Preferably, the thickness of the above-mentioned silver layer is 10 μm, the thickness of the nickel layer is 2 μm, and the thickness of the tin layer is 8 ± 2 μm.

[0013] Compared with the prior art, the beneficial effect of the present utility model is that, without affecting the overall size, by changing the packaging material and packaging structure, a better magnetic shielding effect is achieved, avoiding magnetic leakage interference of the product to adjacent devices and the underlying circuit, and effectively improving the inductance of the product. In addition, the present invention can manufacture smaller product sizes without sacrificing product electrical properties and without increasing additional costs. Description of the Drawings

[0014] Figure 1 is the structure of a conventional wire-wound chip inductor;

[0015] Figure 2 is a schematic diagram of the structure of a small-sized magnetic shielding inductor;

[0016] Figure 3 is a schematic diagram of the electrode structure;

[0017] Figure 4 is Figure 3 a partial enlarged view of A. Detailed Embodiments

[0018] The following will further explain and illustrate the present utility model in conjunction with the drawings of the specification, so as to be better understood by those skilled in the art.

[0019] Embodiment 1

[0020] AsFigures 2 - 4 As shown in Figures 2 - 4 , a small-sized magnetic shielding inductor includes a packaging layer 1, a magnetic core framework 2, a coil body 3, and electrodes 4. The magnetic core framework is in an H shape. The coil body 3 is composed of enameled copper wire and is directly wound around the middle part of the magnetic core framework 2. The two lead-out ends of the coil body 3 are respectively welded to the electrodes 4 to achieve electrical connection. The two electrodes 4 are respectively arranged at the tops of the legs on both sides of the magnetic core framework 2. The coil body 3 and the magnetic core framework 2 are wrapped with the packaging layer 1 on the outside. The packaging layer 1 is made of magnetic material to form a closed magnetic shielding loop.

[0021] Specifically, the packaging layer 1 includes a first packaging layer 11 that wraps around the outside and below of the coil body 3 and the magnetic core framework 2, and a second packaging layer 12 that covers the top of the coil body 3 and the magnetic core framework 2, completely covering the magnetic core framework 2 and the coil body 3. The first packaging layer 11 and the second packaging layer 12 are connected into an integral structure to form a closed magnetic shielding loop, playing a role in magnetic shielding.

[0022] Furthermore, the material of the above-mentioned magnetic core framework 2 is one of ceramic body, ferrite, Fe-Si-Cr, Fe-Si-Al, or Fe-Ni alloy. The surface of the electrode 4 is covered with a silver layer 41, a nickel layer 42, and a tin layer 43 from the inside to the outside in sequence. The thickness of the silver layer 41 is 10 μm, the thickness of the nickel layer 42 is 2 μm, and the thickness of the tin layer 43 is 8 ± 2 μm.

[0023] Embodiment 2

[0024] A manufacturing method of a small-sized magnetic shielding inductor includes the following steps:

[0025] Step 1, winding and thermocompression welding: Wind the coil body 3 with different numbers of turns on the magnetic core framework 2 according to the inductor design and perform thermocompression welding on it. The wound coil body 3 is enameled copper wire and can be wound in multiple layers or single layer;

[0026] Step 2, plastic tape dispensing: Select a plastic tape made of high-temperature resistant material. The length and width dimensions of the plastic tape are 0.1 mm larger than those of the magnetic core framework. Inject magnetic packaging material into the plastic tape by the dispensing method and perform a leveling process through a pneumatic device. The magnetic packaging material is epoxy magnetic glue or UV magnetic glue;

[0027] Step 3, implanting the winding semi-finished product: Implant the semi-finished product of Step 1 into the plastic tape of Step 2 through a suction nozzle;

[0028] Step 4, secondary dispensing: The remaining exposed magnetic core skeleton 2 and the outer side of the coil body 3 are continuously encapsulated with a magnetic encapsulation material, and after completion, it is thermally cured and formed. The curing temperature is 120°C - 150°C, and the time is 30 minutes to form the encapsulation layer 1; the components of the magnetic encapsulation material include radio frequency raw glue, magnetic powder, and terpineol. The mass ratio of the radio frequency raw glue to the glue powder is 1:8, the density of the magnetic powder is 4.1 g / 3m³, and the mass ratio of terpineol in the magnetic encapsulation material is 5.0 ± 0.2%; the viscosity of the magnetic encapsulation material is 20000 ± 30003 p, and the magnetic permeability μi = 10 ± 25%;

[0029] Step 5, appearance screening: Screening by a six-sided AI appearance machine;

[0030] Step 6, electrical sorting: Testing the key parameters of the inductor;

[0031] Step 7, taping.

[0032] Taking the fully magnetic shielded ferrite inductor as an example

[0033] The magnetic material skeleton 2 is ferrite; the coil body 3 is composed of enameled copper wire, directly wound on the magnetic material skeleton 2, and connected to the electrode 4 through thermocompression welding; the encapsulation layer 1 completely wraps the coil and the skeleton body through die encapsulation to form a magnetic closed loop; the surface of the electrode 4 is covered with tin and is electrically connected to the two lead-out ends of the coil body 3. The small-sized magnetic shielded inductor is prepared by the above method, and the characteristics of the inductor products such as L, Q, DCR, ISAT, and IRMS are measured. Under the same position conditions, load current, and inductance conditions, the magnetic leakage of the fully magnetic shielded inductor is 0.15 mT.

[0034] Taking the fully magnetic shielded alloy inductor as an example

[0035] The magnetic material skeleton 2 is FeSiCr / FeSiAl / FeNi alloy; the coil body 3 is composed of enameled copper wire, directly wound on the magnetic material skeleton 2, and connected to the electrode 4 through thermocompression welding; the encapsulation layer 1 completely wraps the coil and the skeleton body through die encapsulation to form a magnetic closed loop; the surface of the electrode 4 is covered with tin and is electrically connected to the two lead-out ends of the coil body 3. The small-sized magnetic shielded inductor is prepared by the above method, and the characteristics of the inductor products such as L, Q, DCR, ISAT, and IRMS are measured. Under the same position conditions, load current, and inductance conditions, the magnetic leakage of the semi-magnetic shielded inductor is 0.15 mT.

[0036] The structure of a conventional wound chip inductor includes UV encapsulation glue, a magnetic core skeleton, a coil body, and an electrode. The coil body is completely surrounded by the UV glue, and this inductor is designed as an open magnetic circuit structure. The magnetic force lines of the product cannot be completely concentrated on the inductor body, and the conventional design scheme cannot play a magnetic shielding role. Under the same position conditions, load current, and inductance conditions, the magnetic leakage of the open magnetic circuit inductor is 0.5 mT.

[0037] The embodiments described above are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the spirit and principles of the design of the present invention, various deformations and improvements made by those skilled in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A small-sized magnetic shielding inductor, characterized in that: The invention comprises an encapsulation layer (1), a magnetic core frame (2), a coil body (3) and electrodes (4); the magnetic core frame (2) is in an H-shape; the coil body (3) is wound around the middle of the magnetic core frame (2); two lead ends are respectively electrically connected to the electrodes (4); the two electrodes (4) are respectively arranged at the top ends of the legs on both sides of the magnetic core frame (2); the outer sides of the coil body (3) and the magnetic core frame (2) are wrapped with the encapsulation layer (1) to form a closed magnetic shielding loop.

2. A small-size magnetic shielding inductor according to claim 1, characterized in that: The packaging layer (1) comprises a first packaging layer (11) wrapped around the outside and below of the coil body (3) and the magnetic core skeleton (2), and a second packaging layer (12) covering the top of the coil body (3) and the magnetic core skeleton (2), the first packaging layer (11) and the second packaging layer (12) being connected to form an integrated structure.

3. The small-size magnetic shielding inductor according to claim 1, characterized in that: The material of the magnetic core skeleton (2) is one of ceramic, ferrite, iron silicon chromium, iron silicon aluminum or iron nickel alloy.

4. The small-size magnetic shielding inductor according to claim 1, characterized in that: The coil body (3) comprises an enameled copper wire, which is directly wound around the magnetic core skeleton (2) and is electrically connected to the electrode (4) by welding.

5. The small-size magnetic shielding inductor according to claim 1, characterized in that: The electrode (4) is covered with a silver layer (41), a nickel layer (42) and a tin layer (43) in sequence from the inside to the outside.

6. The small-size magnetic shielding inductor according to claim 5, characterized in that: The thickness of the silver layer (41) is 10 μm, the thickness of the nickel layer (42) is 2 μm, and the thickness of the tin layer (43) is 8±2 μm.

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