Coil assembly

Abstract

A coil assembly includes a core and a first coil portion and a second coil portion wound on the core to form one or more turns. The core includes a first core portion on which the first coil portion is wound, a second core portion on which the second coil portion is wound, and a third core portion between the first core portion and the second core portion, and the first coil portion and the second coil portion are wound on the third core portion to be superposed on each other.

Description

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2020-0085404, filed July 10, 2020, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety for all purposes. TECHNICAL FIELD

[0002] The present disclosure relates to a coil assembly. BACKGROUND

[0003] An inductor, as a coil assembly, is a representative passive electronic component used together with a resistor and a capacitor in an electronic device.

[0004] As electronic devices have become smaller and better in performance, the number of electronic components used in electronic devices is increasing and the size is being miniaturized.

[0005] Accordingly, there is an increasing demand for a coupled coil assembly for reducing the mounting area of a component. In order to increase the efficiency of a component in the same size, the coupling coefficient can be increased by increasing mutual inductance, or can be appropriately reduced by increasing leakage inductance. For example, it is necessary to adjust the coupling coefficient by appropriately adjusting the mutual inductance and the leakage inductance by appropriately modifying the shape of the coil part of the coupled inductor according to the needs of the art.

[0006] As an example, as a method for adjusting the coupling coefficient without increasing the thickness of the component, there is a case of being wound in a bifilar shape so that a plurality of adjacent conductors are stacked on each other. SUMMARY

[0007] Exemplary embodiments provide a coil assembly having a coupled inductor structure in which mutual inductance between coil parts can be effectively controlled.

[0008] According to an aspect of the present disclosure, a coil assembly includes a core part and a first coil part and a second coil part wound on the core part to form one or more turns. The core part includes a first core part, a second core part, and a third core part, the first coil part is wound on the first core part, the second coil part is wound on the second core part, the third core part is located between the first core part and the second core part, and the first coil part and the second coil part are wound on the third core part to be stacked on each other.

[0009] According to another aspect of the present disclosure, a coil assembly includes a core, and a first coil portion and a second coil portion forming one or more turns wound on the core. The core includes a first core portion, a second core portion, and a third core portion, the first coil portion is wound on the first core portion, the second coil portion is wound on the second core portion, the third core portion is located between the first core portion and the second core portion, and the first coil portion and the second coil portion are wound as a bifilar coil with respect to each other on the third core portion.

[0010] According to another aspect of the present disclosure, a coil assembly includes a core having a first core portion, a second core portion, and a third core portion disposed between the first core portion and the second core portion such that the first core portion, the third core portion, and the second core portion are connected, a first coil portion wound on the first core portion and the third core portion and having a first end wound on the first core portion and a second end wound on a section of the third core portion close to the second core portion, and a second coil portion wound on the second core portion and the third core portion and having a first end wound on the second core portion and a second end wound on a section of the third core portion close to the first core portion to overlap at least a portion of the first coil portion wound on the third core portion. BRIEF DESCRIPTION OF DRAWINGS

[0011] The above and other aspects, features, and advantages of the present inventive concepts will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0012] Figure 1 is a view schematically illustrating a coil assembly according to an embodiment;

[0013] Figure 2 is a view of the coil assembly of Figure 1 from above;

[0014] Figure 3 is a view corresponding to a modification example of the coil assembly according to an embodiment; and Figure 2

[0015] Figure 4 is a view corresponding to another modification example of the coil assembly according to an embodiment. Figure 2 DETAILED DESCRIPTION

[0016] ​​The following detailed description is presented to aid the reader in gaining a comprehensive understanding of the methods, apparatuses, and / or systems described herein. Various changes, modifications, and / or equivalents of the concepts described herein could become apparent to those skilled in the art, however, and the present description is not intended to limit the scope of the concepts to those concepts precisely as described. The sequence of operations in the descriptions of the operations is just one example, and the operations could be performed in other sequences without departing from the teachings of the examples. Additionally, descriptions of functions and structures

[0017] The features described herein can be implemented in different forms and should not be construed as limited to the examples described herein. Rather, these examples have been provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to one of ordinary skill in the art.

[0018] Here, it should be noted that the use of the term "comprise" with respect to embodiments or examples (e.g., an embodiment or example can comprise something or achieve something) means that there is at least one embodiment or example that comprises or achieves the feature, and all embodiments and examples are not limited to this.

[0019] Throughout the specification, when an element (such as a layer, region, or substrate) is referred to as being "on" another element, "connected to" another element, or "coupled to" another element, it can be directly on, directly connected to, or directly coupled to the other element, or one or more other elements can be interposed therebetween. In contrast, when an element is referred to as being "directly on," "directly connected to," or "directly coupled to" another element, there are no other elements interposed therebetween. Also, throughout the specification, the term "on" means positioned above or below a target portion based on a gravity direction, not necessarily positioned above.

[0020] As used herein, the term "and / or" includes any one of the listed items and any combination of two or more of the listed items.

[0021] Although terms such as "first", "second", and "third" can be used herein to describe various components, assemblies, regions, layers, or parts, the components, assemblies, regions, layers, or parts are not limited by these terms. Rather, these terms are used only to distinguish one component, assembly, region, layer, or part from another component, assembly, region, layer, or part. Therefore, the first component, the first assembly, the first region, the first layer, or the first part described in the examples described herein can also be called the second component, the second assembly, the second region, the second layer, or the second part without departing from the teachings of the examples.

[0022] For ease of description, spatially relative terms such as "upper", "above", "lower", and "below" can be used herein for the purpose of describing one element's relationship to another element as illustrated in the figures. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device is turned over in the figure, elements described as being "above" or "up" other elements would then be oriented "below" or "down" the other elements. Thus, the term "above" can encompass both an orientation of above and below. The device can be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative terms used herein interpreted accordingly.

[0023] The terms used herein are merely used to describe various examples and are not intended to limit the disclosure. Singular forms are intended to include plural forms unless the context clearly indicates otherwise. The terms "include", "comprise", and "have" are intended to designate the presence of features, numbers, operations, components, elements, and / or combinations thereof described in the specification but do not preclude the presence or addition of one or more other features, numbers, operations, components, elements, and / or combinations thereof.

[0024] Variations in shapes illustrated in the drawings can occur due to manufacturing techniques and / or tolerances. Thus, the examples described herein are not limited to the specific shapes illustrated in the drawings, but include variations in shapes that occur during manufacturing.

[0025] Features of the examples described herein can be combined in various ways as will be apparent after an understanding of the disclosure of the present disclosure. Also, although examples described herein have various configurations, other configurations are possible as will be apparent after an understanding of the disclosure of the present disclosure.

[0026] The drawings can not be drawn to scale and, for clarity, illustration, and convenience, relative sizes, proportions, and depictions of elements in the drawings can be exaggerated.

[0027] Since the sizes and thicknesses of the respective components illustrated in the drawings are arbitrarily shown for convenience of description, the disclosure is not necessarily limited to the illustration of the drawings.

[0028] In the drawings, an X direction can be defined as a length direction, a Y direction can be defined as a width direction, and a Z direction can be defined as a thickness direction.

[0029] Hereinafter, a coil assembly according to an embodiment will be described in detail with reference to the accompanying drawings, and in the description with reference to the drawings, the same or corresponding components are designated the same reference numerals and a repeated description thereof will be omitted.

[0030] Various types of electronic components are used in electronic devices, and various types of coil components can be appropriately used among the electronic components to remove noise, etc.

[0031] For example, a coil component in an electronic device can be used as a power inductor, a high frequency inductor (HF inductor), a general magnetic bead, a high frequency magnetic bead (GHz magnetic bead), a common mode filter, etc.

[0032] Wound coil assembly

[0033] First embodiment

[0034] Figure 1 FIG. 1 is a view schematically showing a coil component according to an embodiment.

[0035] Figure 2 FIG. 2 is a view of the coil component of FIG. 1 viewed from above. Figure 1

[0036] Figure 3 FIG. 3 is a view of a modification example of the coil component of FIG. 1 according to an embodiment. Figure 2

[0037] Figure 4 FIG. 4 is a view of another modification example of the coil component of FIG. 1 according to an embodiment. Figure 2 Referring to FIG. 1,

[0038] Figures 1 to 4 The coil component 1000 according to an exemplary embodiment can include a core 100 and a coil portion 200 (including a first coil portion 210 and a second coil portion 220).

[0039] The core 100 forms an outer shape of the coil component 1000 according to the present embodiment, and can be formed in a ring shape forming a closed loop.

[0040] ​​​The core 100 includes a first core 110 on which the first coil portion 210, which will be described later, is wound, a second core 120 on which the second coil portion 220 is wound, and a third core 130 disposed between the first core 110 and the second core 120, and the first coil portion 210 and the second coil portion 220 are wound on the third core 130 adjacent to each other to be stacked on each other. The third core 130 can be disposed between the first core 110 and the second core 120 so that the first core 110, the third core 130, and the second core 120 can be connected. For example, the first core 110, the second core 120, and the third core 130 can be three sides of a quadrilateral (for example, rectangular) ring shape, in which the first core 110 and the second core 120 face each other, and the third core 130 is disposed between and connected to the first core 110 and the second core 120, respectively.

[0041] The core 100 can include a magnetic material and an insulating resin. Specifically, the core 100 can be formed by stacking one or more magnetic sheets including an insulating resin and a magnetic material dispersed in the insulating resin. The core 100 can have a different structure other than the structure in which the magnetic material is dispersed in the insulating resin. For example, the core 100 can be formed with a magnetic material such as ferrite.

[0042] The magnetic material can be ferrite or a magnetic metal powder.

[0043] The ferrite can be, for example, one or more of Mg-Zn-based spinel-type ferrite, Mn-Zn-based spinel-type ferrite, Mn-Mg-based spinel-type ferrite, Cu-Zn-based spinel-type ferrite, Mg-Mn-Sr-based spinel-type ferrite, Ni-Zn-based spinel-type ferrite, Ba-Zn-based hexagonal ferrite, Ba-Mg-based hexagonal ferrite, Ba-Ni-based hexagonal ferrite, Ba-Co-based hexagonal ferrite, Ba-Ni-Co-based hexagonal ferrite, and Y-based garnet-type ferrite and Li-based ferrite.

[0044] The magnetic metal powder can include at least one of iron (Fe), silicon (Si), chromium (Cr), cobalt (Co), molybdenum (Mo), aluminum (Al), niobium (Nb), copper (Cu), nickel (Ni), and alloys thereof. For example, the magnetic metal powder can be one or more of pure iron powder, Fe-Si alloy powder, Fe-Si-Al alloy powder, Fe-Ni alloy powder, Fe-Ni-Mo alloy powder, Fe-Ni-Mo-Cu alloy powder, Fe-Co alloy powder, Fe-Ni-Co alloy powder, Fe-Cr alloy powder, Fe-Cr-Si alloy powder, Fe-Si-Cu-Nb alloy powder, Fe-Ni-Cr alloy powder, and Fe-Cr-Al alloy powder.

[0045] The magnetic metal powder can be amorphous or crystalline. For example, the magnetic metal powder can be Fe-Si-B-Cr-based amorphous alloy powder, but is not limited thereto.

[0046] Both the ferrite and the magnetic metal powder can have particles with an average diameter of about 0.1 µm to 30 µm, but are not limited thereto.

[0047] The core 100 can include two or more types of magnetic materials dispersed in an insulating resin. In this case, the magnetic materials being different types means that the magnetic materials dispersed in the insulating resin are distinguished from each other by any one of an average diameter, a composition, a crystallinity, and a shape.

[0048] The insulating resin can include, but is not limited to, an epoxy resin, a polyimide, a liquid crystal polymer, etc., alone or as a mixture.

[0049] The coil portion 200 is wound on the core 100 to exhibit a characteristic of a coil assembly. For example, when the coil assembly 1000 of the present embodiment is used as a power inductor, the coil portion 200 can be used to stabilize power of an electronic device by storing an electric field as a magnetic field and maintaining an output voltage.

[0050] In this embodiment, the first coil portion 210 and the second coil portion 220 can be formed by winding a metal conductor such as a copper conductor in a spiral shape. As described later, an insulating layer (not shown) can be disposed on a surface of each turn of the plurality of turns of the first coil portion 210 and the second coil portion 220.

[0051] The coil portion 200 includes a first coil portion 210 and a second coil portion 220 wound on the core portion 100 to form one turn or more. The first coil portion 210 and the second coil portion 220 wound on the third core portion 130 can be wound as a double wire winding. In this embodiment, the double wire winding refers to a winding including two adjacent insulated conductors. As an example of the above-described double wire winding, the first coil portion 210 and the second coil portion 220 wound on the third core portion 130 can be stacked on each other and / or can be alternately disposed. According to an example, the number of turns of the first coil portion 210 wound on the third core portion 130 can be equal to the number of turns of the second coil portion 220 wound on the third core portion 130.

[0052] Referring to Figure 2 The total number of turns of the first coil portion 210 and the second coil portion 220 wound on the third core portion 130 can be the same as the number of turns of the first coil portion 210 wound on the first core portion 110 or the number of turns of the second coil portion 220 wound on the second core portion 120. Table 1 below shows a coupling coefficient measured by forming a cross-sectional area of the coil portion 200 (for example, an area of a cross-section of each turn of the coil portion 200 perpendicular to a direction along which an axis of the coil portion 200 extends) to be 80 µm x 80 µm and a cross-sectional area of the core portion 100 (for example, an area of a cross-section of the first core portion 110 taken along the X direction-Z direction) to be 300 µm x 300 µm in a coil assembly having a length of 2.5 mm, a width of 2.5 mm, and a thickness of 0.5 mm. For example, the above-described coil assembly is formed such that the number of turns of the first coil portion 210 on the first core portion 110, the number of turns of the second coil portion 220 on the second core portion 120, and the total number of turns of the first coil portion 210 and the second coil portion 220 on the third core portion 130 are the same as each other, and then the coupling coefficient (k) value is measured.

[0053] [Table 1]

[0054] Experimental example Self-inductance Mutual inductance Coupling coefficient (k) 1 0.0806 μH -0.0393 μH -0.488

[0055] Referring to the experimental results in Table 1, when the total number of turns of the first coil portion 210 and the second coil portion 220 on the third core portion 130 is the same as the number of turns of each of the first coil portion 210 on the first core portion 110 and the second coil portion 220 on the second core portion 120, it can be seen that the absolute value of the coupling coefficient is close to about 0.5. According to an embodiment of the disclosure, by forming a region in which coil portions are stacked in a single coil assembly, the coupling coefficient can be adjusted without increasing the size of the assembly.

[0056] Referring to Figure 3The total number of turns of the first coil portion 210 and the second coil portion 220 wound on the third core portion 130 can be greater than the number of turns of the first coil portion 210 wound on the first core portion 110. Also, the total number of turns of the first coil portion 210 and the second coil portion 220 wound on the third core portion 130 can be greater than the number of turns of the second coil portion 220 wound on the second core portion 120. Also, the number of turns of the first coil portion 210 wound on the first core portion 110 can be the same as (as shown in FIG. 1) or different from the number of turns of the second coil portion 220 wound on the second core portion 120. Figure 3

[0057] Referring to FIG. 1, Figure 3 The interval distance between the respective turns (adjacent turns) of the first coil portion 210 and the second coil portion 220 wound on the third core portion 130 can be smaller than the interval distance between the turns of the first coil portion 210 formed on the first core portion 110. Also, the interval distance between the respective turns of the first coil portion 210 and the second coil portion 220 wound on the third core portion 130 can be smaller than the interval distance between the respective turns of the second coil portion 220 formed on the second core portion 120. For example, since the total number of turns of the first coil portion 210 and the second coil portion 220 wound on the third core portion 130 increases, the interval distance between the respective turns of the first coil portion 210 and the second coil portion 220 wound on the third core portion 130 can decrease according to the degree of increase in the number of turns. This configuration is not necessarily limited thereto, and for example, even in the case where the total number of turns of the first coil portion 210 and the second coil portion 220 wound on the third core portion 130 increases, the interval distance between the respective turns of the first coil portion 210 and the second coil portion 220 wound on the third core portion 130 can not decrease.

[0058] Also, referring to FIG. 1, Figure 4 The total number of turns of the first coil portion 210 and the second coil portion 220 wound on the third core portion 130 can be smaller than the number of turns of the first coil portion 210 wound on the first core portion 110. Also, the total number of turns of the first coil portion 210 and the second coil portion 220 wound on the third core portion 130 can be smaller than the number of turns of the first coil portion 210 wound on the first core portion 110. Also, the number of turns of the first coil portion 210 wound on the first core portion 110 can be the same as (as shown in FIG. 1) or different from the number of turns of the second coil portion 220 wound on the second core portion 120. Figure 4

[0059] Referring to FIG. 1, Figure 4 ​​The interval distance between adjacent turns of the first coil portion 210 and the second coil portion 220 wound on the third core portion 130 can be greater than the interval distance between adjacent turns of the first coil portion 210 formed on the first core portion 110. Also, the interval distance between adjacent turns of the first coil portion 210 and the second coil portion 220 wound on the third core portion 130 can be greater than the interval distance between adjacent turns of the second coil portion 220 formed on the second core portion 120. For example, since the total number of turns of the first coil portion 210 and the second coil portion 220 wound on the third core portion 130 is reduced, the interval distance between turns of the first coil portion 210 and the second coil portion 220 wound on the third core portion 130 can increase according to the above reduction. The configuration is not necessarily limited thereto, and for example, even in the case where the total number of turns of the first coil portion 210 and the second coil portion 220 wound on the third core portion 130 is reduced, the interval distance between adjacent turns of the first coil portion 210 and the second coil portion 220 wound on the third core portion 130 can not increase.

[0060] Referring to Figure 2 The first coil portion 210 has one end 211 wound on the third core portion 130 and the other end 212 extended to the first core portion 110 to form turns in the first direction from the one end 211.

[0061] The second coil portion 220 has one end 221 wound on the third core portion 130 and the other end 222 extended to the second core portion 120 to form turns in the second direction from the one end 221. For example, the first direction and the second direction, which are the directions of rotation of the first coil portion 210 and the second coil portion 220, respectively, can be opposite to each other.

[0062] The one end 211 of the first coil portion 210 is disposed between the one end 221 and the other end 222 of the second coil portion 220, and the one end 221 of the second coil portion 220 can be disposed between the one end 211 and the other end 212 of the first coil portion 210.

[0063] In this embodiment, the first coil portion 210 and the second coil portion 220 can be wound in the same direction or can be wound in different directions. In these cases, when the number of turns of the first coil portion 210 and the second coil portion 220 wound on the third core portion 130 increases, mutual inductance between the first coil portion 210 and the second coil portion 220 increases, and the coupling coefficient can increase.

[0064] On the other hand, when the number of turns of the first coil portion 210 and the second coil portion 220 wound on the third core portion 130 is reduced, the mutual inductance between the first coil portion 210 and the second coil portion 220 is reduced, resulting in a reduction in the coupling coefficient. For example, by increasing or reducing the number of turns of the first coil portion 210 and the second coil portion 220 wound on the third core portion 130, the coupling coefficient of the coil assembly can be easily adjusted.

[0065] In some embodiments, for example, with reference to Figure 2 , the first coil portion 210 and the second coil portion 220 can be wound in different directions. In this case, the direction of the magnetic flux formed inside the third core portion 130 by the first coil portion 210 and the direction of the magnetic flux formed inside the third core portion 130 by the second coil portion 220 are opposite to each other, thereby canceling the magnetic flux. In this case, as described above, when the number of turns of the first coil portion 210 and the second coil portion 220 wound on the third core portion 130 is increased, the mutual inductance between the first coil portion 210 and the second coil portion 220 is increased, and thus the coupling coefficient is increased. On the contrary, when the number of turns of the first coil portion 210 and the second coil portion 220 wound on the third core portion 130 is reduced, the mutual inductance between the first coil portion 210 and the second coil portion 220 is reduced, and thus the coupling coefficient is reduced.

[0066] In the case of the coupling inductor of the related art, the coupling coefficient is adjusted using the thickness between the upper coil portion and the lower coil portion, but there are problems of a limitation in reducing the thickness of the coil portion and an increase in the size of the assembly when the distance between the coil portions is increased. In the case of this embodiment of the present disclosure, by forming the region in which the respective coil portions are stacked in a single coil portion, the coupling coefficient can be adjusted without increasing the size of the assembly in the X-Y plane having a relative spatial margin.

[0067] An insulating layer (not shown) can be provided along the surfaces of the coil portions 210 and 220. The insulating layer (not shown) serves to protect and insulate the turns of the first coil portion 210 and the second coil portion 220, and can include a known insulating material such as parylene. Any insulating material included in the insulating layer (not shown) can be used, and is not particularly limited. The insulating layer (not shown) can be formed by a method such as vapor deposition, but is not limited thereto.

[0068] Second embodiment

[0069] The coil assembly according to the second embodiment differs from the coil assembly according to the first embodiment in that the coil portion 200 is formed by plating. Accordingly, in describing the present embodiment, only the coil portion 200 different from the first embodiment will be described. For the remaining configuration of the present embodiment, the description in the first embodiment can be applied as is.

[0070] The first coil portion 210 and the second coil portion 220 can be formed using a seed layer and at least one plating layer formed on the seed layer.

[0071] For example, when the first coil portion 210 and the second coil portion 220 are formed by plating one surface of the core portion 100, the first coil portion 210 and the second coil portion 220 can include a seed layer such as an electroless plating layer and an electroplating layer. In this case, the electroplating layer can have a single layer structure or a multi-layer structure. The electroplating layer of the multi-layer structure can be formed to have a conformal film structure in which one electroplating layer is covered with another electroplating layer, or can be formed to have a shape in which another electroplating layer is stacked only on one surface of one electroplating layer. The first coil portion 210 and the second coil portion 220 can be formed using a conductive material such as copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), and titanium (Ti), or an alloy thereof, but the material thereof is not limited thereto

[0072] As described above, according to an exemplary embodiment, by winding in a double wire shape such that a plurality of adjacent conductors are stacked on each other, the coupling coefficient can be adjusted to a desired value without increasing the thickness of the assembly.

[0073] While the present disclosure includes specific examples, it will be apparent to one ordinarily skilled in the art that various changes in form and detail can be made without departing from the spirit and scope of the claims and their equivalents. The examples described herein are to be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects in each example are to be considered as being applicable to similar features or aspects in other examples. Suitable results can be achieved if the described techniques are performed in a different order, and / or if components in the described systems, architectures, devices, or circuits are combined in a different manner, and / or if the described systems, architectures, devices or circuits are implemented using other components or their equivalents. Therefore, the scope of the disclosure is defined not by the specific embodiments discussed, but by the appended claims and their equivalents, and all variations within the scope of the claims and their equivalents are to be construed as being included in the disclosure.

Claims

1. A coil assembly comprising: a core; and a first coil portion and a second coil portion wound on the core to form one or more turns, wherein the core includes a first core portion, a second core portion, and a third core portion, the first coil portion is wound on the first core portion, the second coil portion is wound on the second core portion, the third core portion is located between the first core portion and the second core portion, and the first coil portion and the second coil portion are wound on the third core portion to be superposed with each other, and wherein the first coil portion is not wound on the second core portion, and the second coil portion is not wound on the first core portion.

2. The coil assembly of claim 1, wherein, The first coil portion and the second coil portion wound on the third core portion are alternately arranged with each other.

3. The coil assembly of claim 1, wherein, A total number of turns of the first coil portion and the second coil portion wound on the third core portion is the same as a number of turns of the first coil portion wound on the first core portion and / or a number of turns of the second coil portion wound on the second core portion.

4. The coil assembly of claim 1, wherein, A total number of turns of the first coil portion and the second coil portion wound on the third core portion is greater than a number of turns of the first coil portion wound on the first core portion.

5. The coil assembly of claim 1, wherein, A total number of turns of the first coil portion and the second coil portion wound on the third core portion is greater than a number of turns of the second coil portion wound on the second core portion.

6. The coil assembly of claim 1, wherein, A total number of turns of the first coil portion and the second coil portion wound on the third core portion is less than a number of turns of the first coil portion wound on the first core portion.

7. The coil assembly of claim 1, wherein, A total number of turns of the first coil portion and the second coil portion wound on the third core portion is less than a number of turns of the second coil portion wound on the second core portion.

8. The coil assembly of any one of claims 1 to 7, wherein, The first coil portion has one end wound on the third core portion and another end extending from the one end of the first coil portion to the first core portion to form turns in a first direction, and the second coil portion has one end wound on the third core portion and another end extending from the one end of the second coil portion to the second core portion to form turns in a second direction.

9. The coil assembly of claim 8, wherein, The first direction and the second direction are opposite to each other.

10. The coil assembly of claim 8, wherein, The one end of the first coil portion is disposed between the one end and the another end of the second coil portion, and The one end of the second coil portion is disposed between the one end and the another end of the first coil portion.

11. The coil assembly of claim 1, 4, or 5, wherein, A separation distance between adjacent turns of the first coil portion and the second coil portion wound on the third core portion is less than a separation distance between adjacent turns of the first coil portion wound on the first core portion.

12. The coil assembly of claim 1, 6, or 7, wherein, A separation distance between adjacent turns of the first coil portion and the second coil portion wound on the third core portion is greater than a separation distance between adjacent turns of the first coil portion wound on the first core portion.

13. The coil assembly of claim 1, wherein, The core constitutes a closed loop.

14. The coil assembly of claim 1, wherein, The first coil portion and the second coil portion include a copper conductor coated with an insulating layer.

15. The coil assembly of claim 1, wherein, The first coil portion and the second coil portion include a plating layer. 16.A coil assembly comprising: a core; and a first coil portion and a second coil portion forming one or more turns wound on the core, wherein the core portion includes a first core portion, a second core portion, and a third core portion, the first coil portion is wound around the first core portion, the second coil portion is wound around the second core portion, the third core portion is located between the first core portion and the second core portion, and the first coil portion and the second coil portion are wound as a double wire coil with respect to each other on the third core portion, and wherein the first coil portion is not wound around the second core portion, and the second coil portion is not wound around the first core portion.

17. A coil assembly comprising: a core portion having a first core portion, a second core portion, and a third core portion, the third core portion being disposed between the first core portion and the second core portion such that the first core portion, the third core portion, and the second core portion are connected; a first coil portion wound around the first core portion and the third core portion and having a first end wound around the first core portion and a second end wound around a section of the third core portion proximate to the second core portion; a second coil portion wound around the second core portion and the third core portion and having a first end wound around the second core portion and a second end wound around a section of the third core portion proximate to the first core portion so as to overlap at least a portion of the first coil portion wound around the third core portion, wherein the first coil portion is not wound around the second core portion, and the second coil portion is not wound around the first core portion.

18. The coil assembly of claim 17, wherein, a number of turns of the first coil portion wound around the third core portion is equal to a number of turns of the second coil portion wound around the third core portion.

19. The coil assembly of claim 17, wherein, the first core portion, the second core portion, and the third core portion are three sides of a quadrilateral ring shape, wherein the first core portion and the second core portion are opposite each other, and the third core portion is disposed between and connected to the first core portion and the second core portion, respectively.

20. The coil assembly of claim 17, wherein, a winding direction of the first coil portion around the first core portion and the third core portion is the same as or opposite to a winding direction of the second coil portion around the second core portion and the third core portion.

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