KR101044112B1 - Power inductor - Google Patents

Abstract

We present a power inductor that prevents the opening of internal conductor pattern when surge current is introduced. The proposed power inductor has a ring-shaped inner conductor formed on each of a plurality of stacked insulator sheets, and forms a coil by interconnection of the formed inner conductors, and the power inductor connected to an external electrode opposite to each other of the coil, the inner The conductor is spaced apart from each other so that the inner end and the outer end overlap each other in the same insulator sheet, and the inner end has a convex portion, and one side of the outer end opposite to the convex portion of the inner end is provided with a recess and a recess of the outer end. Convex portions are formed on the other side of the corresponding outer end. The line width between the concave and convex portions of the outer end portion is made equal to the line width between the corresponding portion of the concave portion and the other portions except the convex portion of the outer end portion in the same insulator sheet, thereby eliminating the bottleneck in the pattern of the inner conductor. It is possible to prevent the opening of the internal conductor due to surge current inflow without degrading the DC overlapping characteristic.

Description

Power Inductor

The present invention relates to a power inductor, and more particularly, to a chip-shaped power inductor mainly used in a power supply circuit.

In general, a stacked power inductor is a structure in which an electrode pattern is formed inside a core magnetic body in which a plurality of magnetic layers are stacked, and magnetically saturates at a low current in comparison with a winding power inductor.

As described above, since the coil is surrounded by the magnetic material, the multilayer power inductor generates less magnetic leakage and has a stacked chip structure. As a result, the multilayer power inductor has an advantage of miniaturization and thinning compared to the winding type.

However, despite these advantages, the multilayer power inductor mainly used in a power circuit such as a DC-DC converter has a disadvantage in that abrupt inductance decreases due to magnetic saturation of a magnetic material.

Therefore, at present, various studies have been conducted to prevent such a sudden decrease in inductance, that is, a decrease in DC overlapping characteristics.

Thereby, the technical contents for further improving the DC overlapping characteristics have been disclosed.

FIG. 1 is a diagram illustrating an internal structure of a conventional multilayer inductor, and FIG. 2 is a diagram for describing an inner conductor of FIG. 1. The ends (outer end 30a, inner end 30b) of the inner conductors 20a and 20b have a circular arc shape, and are rounded so that the attachment portion 32a near the outer end 30a is inward. The arc radius of the inner end 30b is smaller than the arc radius of the attachment portion 32a of the outer end 30a in the staggered position relationship. In this case, since the line widths W2a and W2b at the ends are wide, reliable via connection is possible, and the inner area covered by the one-turn inner conductors 20a and 20b is increased by staggering the attachment portion. It is possible to increase the volume of the inner core. In addition, by making the inner conductors 20a and 20b one turn, the volume of the upper core 28a and the lower core 28b can also be increased. Reference numeral 22 is a magnetic material, and 26 is a coil forming part.

By the way, looking at the arrow A, B in Figure 2 it can be seen that the bottle neck (bottle neck) portion is present in the inner conductor (20a, 20b). That is, the attachment part 32a of the outer edge part 30a becomes a bottleneck part. Since the line width W3a of the attachment portion 32a of the outer end 30a is relatively narrow compared to the line widths W1, W2a, W2b, and W3b of other sites, when the surge voltage (current) is repeatedly inputted, the outer end 30a It was found that the attachment portion 32a of the) is mainly disconnected and opened.

The present invention has been proposed in view of the above-described conventional situation, and an object thereof is to provide a power inductor capable of preventing a pattern opening of an internal conductor during surge current inflow.

In order to achieve the above object, a power inductor according to a preferred embodiment of the present invention, a coil-like inner conductor is formed on each of a plurality of stacked insulator sheets, and a coil is formed by interconnection of the inner conductors formed therein. A power inductor connected to an external electrode opposite to each other of

The inner conductors are staggered with the inner and outer ends spaced apart from each other in the same insulator sheet,

The inner end has a convex portion, and a concave portion is formed on one side of the outer end opposite to the convex portion of the inner end, and a convex portion is formed on the other side of the outer end corresponding to one side on which the concave portion of the outer end is formed.

Preferably, the line width between the concave portion and the convex portion at the outer end is equal to the line width between the corresponding portion among the other portions except the concave portion and the convex portion at the outer end in the same insulator sheet.

According to the present invention having such a configuration, the inner conductor is made to have the same line width between the concave portion and the convex portion at the outer end as the line width between the corresponding portion among the other portions except the concave portion and the convex portion at the outer end in the same insulator sheet. By eliminating the bottleneck in the pattern, it is possible to prevent the opening of the inner conductor due to the surge current inflow without degrading the DC overlapping characteristic.

Hereinafter, a power inductor according to an embodiment of the present invention will be described with reference to the accompanying drawings. Prior to the detailed description of the present invention, the terms or words used in the specification and claims described below should not be construed as being limited to the ordinary or dictionary meanings. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only one of the most preferred embodiments of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

3 is an explanatory diagram showing an internal structure of a power inductor according to an embodiment of the present invention, Figure 4 is an explanatory diagram of the inner conductor shown in FIG.

The power inductor according to the embodiment of the present invention includes an insulator layer 50 forming a coil forming portion, an upper core 70 formed on the insulator layer 50, and a lower core 80 formed under the insulator layer 50. ).

The upper core 70 and the lower core 80 are each formed by stacking a plurality of magnetic sheets 52 as necessary. The magnetic sheet 52 has the property of electrical insulation. The magnetic sheet 52 can be said to be an example of the insulator sheet described in the claims of the present invention.

As for the insulator layer 50, two types of internal conductors 56a and 56b of pattern shape are alternately laminated | stacked. The inner conductors 56a and 56b are formed on the upper surface of each magnetic sheet 52 by screen printing or the like.

The lead conductor 54a is formed in the magnetic sheet 52 located at the top of the insulator layer 50, and the lead conductor 54b is formed in the magnetic sheet 52 located at the bottom of the insulator layer 50. do. The lead conductors 54a and 54b are connected to an external terminal (not shown) of the power inductor. The lead conductors 54a and 54b can be formed by, for example, a screen printing method.

The inner conductors 56a and 56b are formed, for example, in a pattern wound in one rotational ring shape, and both ends of each inner conductor 56a and 56b are spaced apart from each other on the upper surface of the corresponding magnetic sheet 52. . This will be described in more detail with reference to FIG. 4. The inner conductor 56a is patterned in the form of one rotation on the upper surface of the magnetic sheet 52, and both ends 58 and 60 of the inner conductor 56a are staggered while being spaced apart from each other. In Fig. 4, reference numeral 58 denotes an inner end of the inner conductor 56a, and reference numeral 60 denotes an outer end of the inner conductor 56a. The inner end 58 has a convex portion 58a rounded convexly outward toward the outer end 60. The outer end 60 has a concave portion 60a and a convex portion 60b. The concave portion 60a of the outer end portion 60 is opposed to the convex portion 58a of the inner end portion 58, and the convex portion 60b of the outer end portion 60 is the concave portion 60a of the outer end portion 60. Is formed on the other side of the outer end portion 60 corresponding to one side formed. The distance b (line width) between the concave portion 60a and the convex portion 60b of the outer end portion 60 is the same as the concave portion 60a and the convex portion 60b of the outer end portion 60 in the magnetic sheet 52. It is equal to the distance (a; line width) between corresponding portions among other portions except for.

The lead conductors 54a and 54b and the inner conductors 56a and 56b are interconnected by via holes (not shown).

In the embodiment of the present invention, the distance (b; line width) between the concave portion 60a and the convex portion 60b of the outer end portion 60 is equal to the distance (a; line width) between other portions as compared with the prior art. This is to prevent the opening of the inner conductor due to surge current inflow without degrading the DC overlapping characteristics. Conventionally, an open occurred at the bottle neck portion (in FIG. 2, arrows A and B portions) at the time of surge current inflow. However, as in the embodiment of the present invention, if the distance b between the concave portion 60a and the convex portion 60b of the outer end 60 is equal to the distance a between the other portions, the bottleneck portion is removed. In comparison with the related art, the opening in the corresponding site is not generated.

The applicant has made several surge tests with the configuration of the embodiment of the present invention, and the results are shown in Table 1 below. EACT-E501B Surge Generator was used as a measuring device for the surge test. Current Wave Form is 8/20 / Current. The sample of the present invention is 2012 size and has an inductance of 4.7 μH. For the sample, a voltage of 300 V at the first, 400 V at the second, 450 V at the third, 500 V at the fourth, and 550 V at the fifth was applied, and then a short or open was confirmed by measuring the inductance. In Table 1 below, the third-party (B company) product is a product having the configuration mentioned in the prior art description.

(Table 1)

    division         Invention      Third party (A company) product      Other company's (B company) product   sample amount           20            10            7
Applied voltage
Bad
Number of occurrences
accumulate
Bad
accumulate
Defective rate
Bad
Number of occurrences
accumulate
Bad
accumulate
Defective rate
Bad
Number of occurrences
accumulate
Bad
accumulate
Defective rate     300 V    -    -   0%    -    -   0%    -    -   0%     400 V    -    -   0%    2    2   20%    -    -   0%     450 V    -    -   0%    One    3   30%    -    -   0%     500 V    -    -   0%    -    3   30%    -    -   0%     550 V    -    -   0%    -    3   30%    5    5 71.4%

As shown in Table 1, the power inductor according to the embodiment of the present invention was not open at all, but it can be seen that the failure occurs in the other conventional power inductors.

5 is a modification of the embodiment of the present invention. The inner conductor 56a shown in FIG. 5 is reversed only in the winding direction compared to the inner conductor 56a shown in FIG. 4, and the rest thereof are the same. That is, even if the winding direction is reversed in comparison with FIG. 4, the distance b (line width) between the concave portion 60a and the convex portion 60b of the outer end 60 is equal to the distance a (line width) between other portions. In this case, the pattern open of the inner conductor due to the surge current is not generated.

On the other hand, the present invention is not limited only to the above-described embodiments and can be carried out by modifications and variations within the scope not departing from the gist of the present invention, the technical idea that such modifications and variations are also within the scope of the claims Must see

1 is an explanatory view showing the internal structure of a conventional stacked power inductor.

FIG. 2 is an explanatory view of the inner conductor shown in FIG. 1. FIG.

3 is an explanatory diagram showing an internal structure of a power inductor according to an embodiment of the present invention.

4 is an explanatory diagram of the inner conductor shown in FIG. 3.

5 is a modification of the embodiment of the present invention.

Description of the Related Art

50: insulator layer 52: magnetic sheet

54a, 54b: lead conductor 56a, 56b: inner conductor

58: inner end 60: outer end

70: upper core 80: lower core

Claims (2)

A power inductor having a ring-shaped inner conductor formed on each of a plurality of stacked insulator sheets, the coil being formed by the interconnection of the formed inner conductors, and connected to external electrodes having opposite ends of the coil, The inner conductors are staggered with the inner and outer ends spaced apart from each other in the same insulator sheet, The inner end has a convex portion, and a concave portion is formed on one side of the outer end opposite to the convex portion of the inner end, and a convex portion is formed on the other side of the outer end corresponding to one side on which the concave portion of the outer end is formed. Power inductor. The method according to claim 1, The line width between the concave portion and the convex portion of the outer end portion is the same as the line width between the corresponding portion among the other portions except the concave portion and the convex portion of the outer end portion in the same insulator sheet.

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