EP4607550A1

EP4607550A1 - Transformer

Info

Publication number: EP4607550A1
Application number: EP23895061.2A
Authority: EP
Inventors: Inseong SOHN; Taekhoon NAM; Jichang Ryu
Original assignee: LG Innotek Co Ltd
Current assignee: LG Innotek Co Ltd
Priority date: 2022-11-25
Filing date: 2023-11-24
Publication date: 2025-08-27
Also published as: WO2024112134A1; CN120266234A; KR20240077858A

Abstract

A transformer according to an embodiment may comprise: a core unit including an upper core and a lower core; and a coil unit which includes a first coil and a second coil and a portion of which is disposed in the core unit, wherein the first coil includes an 11th coil and a 12th coil disposed spaced apart from each other along a first direction on a plane, and the second coil is disposed between the 11th coil and the 12th coil.

Description

[Technical Field]

The present disclosure relates to a transformer.

[Background Art]

In general, driving power is required in order to drive an electronic device, and a power supply device, such as a power supply unit (PSU), is essentially employed in order to supply driving power to the electronic device.
In particular, a display device, such as a flat panel TV, is required to be slim, and is continually being embodied in increasingly larger sizes. Accordingly, it is necessary to reduce the thickness of such a large-scale display while meeting the increased power requirements thereof.
In the power supply unit (PSU), a transformer occupies a relatively large volume compared to other elements. In order to realize a slim transformer, a method of omitting thick elements from the transformer or adjusting the number thereof is generally considered. For example, in recent years, a bobbin, around which a primary coil and a secondary coil are wound so as to be secured thereto, has been omitted from a transformer constituting a power supply unit of a flat panel display device, or a plurality of low-capacity slim transformers has been adopted.
In conventional slim transformers, due to thickness constraints, a horizontal winding structure in which primary and secondary coils are disposed horizontally is adopted.
In the horizontal winding structure, leakage inductance of the transformer is generated according to the spacing distance between the primary winding and the secondary winding.
For example, the typical operating frequency of EVDD in a TV PSU is 100 to 150 kHz. However, when high-frequency tuning is performed to reduce the size and thickness of magnetic components, the operating frequency may exceed 200 kHz. As a result, the required value of leakage inductance for each component may be reduced compared to conventional components.
Conventionally, however, even when the spacing distance between the primary winding and the secondary winding is reduced, reduction in leakage inductance value is limited to a certain extent. Furthermore, due to the slimmed configuration, application of a vertical winding structure is not feasible.
Therefore, there is a need for a transformer capable of reducing the value of leakage inductance (L_L value) compared to conventional slim transformers.

[Disclosure]

[Technical Problem]

A technical task of the present disclosure is to provide a transformer that enables a further slimmed structure and a reduction in leakage inductance value by dividing a primary coil and disposing a secondary coil between the divided primary coils.
The technical tasks of the present disclosure are not limited to the above-mentioned technical tasks, and other technical tasks not mentioned herein will be clearly understood by those skilled in the art from the following description.

[Technical Solution]

A transformer according to an embodiment may include a core unit including an upper core and a lower core and a coil unit including a first coil and a second coil, a portion of the coil unit being disposed inside the core unit. The first coil may include an eleventh coil and a twelfth coil disposed to be spaced apart from each other in a first direction on a plane, and the second coil may be disposed between the eleventh coil and the twelfth coil.
In an example, at least one of the eleventh coil, the twelfth coil, or the second coil may include a triple insulated wire and be coated.
A transformer according to another embodiment may include a core unit including an upper core and a lower core, a coil unit including a first coil and a second coil, a portion of the coil unit being disposed inside the core unit, and a bobbin unit disposed between the core unit and the coil unit. The first coil may include an eleventh coil and a twelfth coil partially disposed in the bobbin unit and spaced apart from each other in a first direction on a plane, and the second coil may be partially disposed in the bobbin unit and may be disposed between the eleventh coil and the twelfth coil.
In an example, the bobbin unit may include a first bobbin configured to accommodate the first coil and a second bobbin including a second accommodation portion formed therein to accommodate the second coil. The first bobbin may include an eleventh bobbin including an eleventh accommodation portion formed therein to accommodate the eleventh coil and a twelfth bobbin disposed to be spaced apart from the eleventh bobbin in the first direction and including a twelfth accommodation portion formed therein to accommodate the twelfth coil.
In an example, the second bobbin may be disposed between the eleventh bobbin and the twelfth bobbin.
In an example, the twelfth bobbin may include a first pin conductively connected to the first coil, and the first pin may include an eleventh pin conductively connected to the eleventh coil, a twelfth pin conductively connected to the twelfth coil, and a thirteenth pin conductively connected to the eleventh coil and the twelfth coil.
In an example, the eleventh coil may be formed with a first number of turns, and the twelfth coil may be formed with a second number of turns. The sum of the first number of turns and the second number of turns may be constant.
In an example, the second coil may be spaced apart from the eleventh coil by a first distance in the first direction and may be spaced apart from the twelfth coil by a second distance in the first direction. The sum of the first distance and the second distance may be constant.
In an example, the width of the second coil measured in the first direction may be less than the sum of the width of the eleventh coil measured in the first direction and the width of the twelfth coil measured in the first direction.
In an example, the height of the second coil measured in a third direction intersecting the first direction may be less than the sum of the height of the eleventh coil measured in the third direction and the height of the twelfth coil measured in the third direction.
In an example, the core unit may include a first outer leg portion, a second outer leg portion, a center leg portion disposed between the first outer leg portion and the second outer leg portion, a first accommodation space defined between the first outer leg portion and the center leg portion to accommodate the eleventh coil, the second coil, and the twelfth coil, and a second accommodation space defined between the second outer leg portion and the center leg portion to accommodate the eleventh coil, the second coil, and the twelfth coil.
In an example, the eleventh coil may be disposed closer to the center leg portion than the second coil, and the second coil may be disposed closer to the center leg portion than the twelfth coil.
A transformer according to still another embodiment may include a core unit including an upper core and a lower core and a coil unit including a first coil, a second coil, and a third coil, a portion of the coil unit being disposed inside the core unit. The first coil and the third coil may be disposed to be spaced apart from each other in a first direction on a plane, and the second coil may be disposed between the first coil and the third coil.
In an example, at least one of the first coil, the second coil, or the third coil may include a triple insulated wire and be coated.
A transformer according to a further embodiment may include a core unit including an upper core and a lower core, a coil unit including a first coil, a second coil, and a third coil, a portion of the coil unit being disposed inside the core unit, and a bobbin unit disposed between the core unit and the coil unit. The first coil and the third coil may be partially disposed in the bobbin unit and may be spaced apart from each other in a first direction on a plane, and the second coil may be partially disposed in the bobbin unit and may be disposed between the first coil and the third coil.
In an example, the bobbin unit may include a first bobbin including a first accommodation portion formed therein to accommodate the first coil, a second bobbin including a second accommodation portion formed therein to accommodate the second coil, and a third bobbin including a third accommodation portion formed therein to accommodate the third coil. The third bobbin may be disposed to be spaced apart from the first bobbin in the first direction.
In an example, the second bobbin may be disposed between the first bobbin and the third bobbin.
In an example, the third bobbin may include a first pin conductively connected to the first coil, a plurality of second pins conductively connected to the second coil, a third pin conductively connected to the third coil, and a fourth pin disposed between the first pin and the third pin and conductively connected to the first coil and the third coil.
In an example, the first coil may be formed with a first number of turns, and the third coil may be formed with a second number of turns. The sum of the first number of turns and the second number of turns may be constant.
In an example, the second coil may be spaced apart from the first coil by a first distance in the first direction and may be spaced apart from the third coil by a second distance in the first direction. The sum of the first distance and the second distance may be constant.
In an example, the width of the second coil measured in the first direction may be less than the sum of the width of the first coil measured in the first direction and the width of the third coil measured in the first direction.
In an example, the height of the second coil measured in a third direction intersecting the first direction may be less than the sum of the height of the first coil measured in the third direction and the height of the third coil measured in the third direction.
In an example, the core unit may include a first outer leg portion, a second outer leg portion, a center leg portion disposed between the first outer leg portion and the second outer leg portion, a first accommodation space defined between the first outer leg portion and the center leg portion to accommodate the first coil, the second coil, and the third coil, and a second accommodation space defined between the second outer leg portion and the center leg portion to accommodate the first coil, the second coil, and the third coil.
In an example, the first coil may be disposed closer to the center leg portion than the second coil, and the second coil may be disposed closer to the center leg portion than the third coil.

[Advantageous Effects]

The transformer according to an embodiment enables a further slimmed structure and a reduction in leakage inductance value by dividing a primary coil and disposing a secondary coil between the divided primary coils.
In addition, the transformer according to an embodiment may reduce an area for a magnetic component by eliminating an internal required spacing distance compared to the conventional transformer.
In addition, the transformer according to an embodiment may prevent the occurrence of defective samples caused by coil assembly tolerances by maintaining a uniform internal magnetic field of the transformer.
In addition, the transformer according to an embodiment may be slimmed by removing a bobbin between a core and a coil unit.
The effects achievable through the present disclosure are not limited to the above-mentioned effects, and other effects not mentioned herein will be clearly understood by those skilled in the art from the following description.

[Description of Drawings]

FIG. 1 is a plan view of a transformer according to an embodiment of the present disclosure.
FIG. 2 is a cross-sectional view taken along line A-A' in FIG. 1.
FIG. 3 is an enlarged view of a first accommodation space.
FIGs. 4 and 5 are enlarged views of FIG. 2.
FIG. 6 is a graph showing the data of Table 1.
FIG. 7 is a cross-sectional view of a transformer according to another embodiment of the present disclosure.
FIG. 8 is a cross-sectional view of a transformer according to still another embodiment of the present disclosure.
FIG. 9 is an enlarged view of portion A in FIG. 8.

[Best Mode]

The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which various embodiments are shown. The examples, however, may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. It is to be understood that the present disclosure covers all modifications, equivalents, and alternatives falling within the scope and spirit of the present disclosure.
While ordinal numbers including "second", "first", etc. may be used to describe various components, they are not intended to limit the components. These expressions are used only to distinguish one component from another component. For example, a second element could be termed a first element, and, similarly, a first element could be termed a second element, without departing from the scope of the present disclosure. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.
In the description of the embodiments, it will be understood that when an element, such as a layer (film), a region, a pattern or a structure, is referred to as being "on" or "under" another element, such as a substrate, a layer (film), a region, a pad or a pattern, the term "on" or "under" means that the element is "directly" on or under another element or is "indirectly" formed such that an intervening element may also be present. It will also be understood that criteria of on or under is on the basis of the drawing. In addition, the thickness or size of a layer (film), a region, a pattern or a structure shown in the drawings may be exaggerated, omitted or schematically drawn for the clarity and convenience of explanation, and may not accurately reflect the actual size.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments of the disclosure. As used herein, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the term "include" or "have", when used herein, specifies the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.
Unless otherwise defined, all terms used herein, which include technical or scientific terms, have the same meanings as those generally appreciated by those skilled in the art. The terms, such as ones defined in common dictionaries, should be interpreted as having the same meanings as terms in the context of pertinent technology, and should not be interpreted as having ideal or excessively formal meanings unless clearly defined in the specification.
Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. The same or equivalent elements are denoted by the same reference numerals even when they are depicted in different drawings, and redundant descriptions thereof will be omitted. In addition, the embodiments will be described using the Cartesian coordinate system, but may also be described using other coordinate systems. In the Cartesian coordinate system, the x-axis, the y-axis, and the z-axis shown in each drawing are perpendicular to each other, but the embodiments are not limited thereto. The x-axis, the y-axis, and the z-axis may intersect each other obliquely.
Hereinafter, a transformer according to an embodiment will be described in detail with reference to the accompanying drawings.
FIG. 1 is a plan view of a transformer according to an embodiment of the present disclosure. FIG. 2 is a cross-sectional view taken along line A-A' in FIG. 1. FIG. 3 is an enlarged view of a first accommodation space. FIGs. 4 and 5 are enlarged views of FIG. 2.
Referring to FIGs. 1 and 2, a transformer 100 according to an embodiment of the present disclosure may include a core unit 110, a bobbin unit 120, and a coil unit 130. Hereinafter, respective components will be described in detail.
The core unit 110 may have the characteristics of a magnetic circuit and thus may act as a path for magnetic flux. The core unit 110 may include an upper core 111 coupled at an upper position and a lower core 112 coupled at a lower position.
The upper core 111 and the lower core 112 may be formed to be symmetrical or asymmetrical with each other in the vertical direction. However, for convenience of explanation, the following description is provided based on an assumption that the two cores are vertically symmetrical.
Each of the upper core 111 and the lower core 112 may include a body portion having a flat plate shape and a plurality of leg portions OL1-1, OL1-2, OL2-1, OL2-2, CL1, and CL2 protruding from the body portion in a thickness direction (i.e. a Z-axis direction or a third direction) and extending in a predetermined direction.
For example, the plurality of leg portions OL1-1, OL1-2, and CL1 of the upper core 111 may include two outer legs OL1-1 and OL1-2 extending in a long-axis direction (e.g., a Y-axis or second direction) and spaced apart from each other in a short-axis direction (e.g., an X-axis or first direction) on a plane and one center leg CL1 disposed between the two outer legs OL1-1 and OL1-2.
When the upper core 111 and the lower core 112 are coupled to each other in the vertical direction, the outer legs OL1-1 and OL1-2 and the center leg CL1 of the upper core 111 may face the outer legs OL2-1 and OL2-2 and the center leg CL2 of the lower core 112, respectively.
For example, one pair of outer legs OL1-1 and OL2-1 facing each other may be referred to as a first outer leg portion, the other pair of outer legs OL1-2 and OL2-2 facing each other may be referred to as a second outer leg portion, and the pair of center legs CL1 and CL2 facing each other may be referred to as a center leg portion.
A gap of a predetermined distance may be defined between at least one of the pair of outer legs OL1-1 and OL2-1, the pair of outer legs OL1-2 and OL2-2, or the pair of center legs CL1 and CL2, which face each other. For example, the gap of a predetermined distance may be 10 µm to 200 µm. However, the disclosure is not necessarily limited thereto.
The inductance of the core unit 110 may be controlled by adjusting the sizes of the gaps defined between the pair of center legs CL1 and CL2 and between each of the two pairs of outer legs OL1-1 and OL2-1, and OL1-2 and OL2-2, and heat generation may be controlled according to the number of gaps.
In addition, the core unit 110 may include a magnetic material, such as iron or ferrite, but the disclosure is not necessarily limited thereto.
The core unit 110 surrounds a portion of the outer periphery of the bobbin unit 120, and accordingly, a portion of a primary coil 131 and 133 and a portion of a secondary coil 132, which are accommodated in the bobbin unit 120, may be disposed inside the core unit 110.
In addition, when the upper core 111 and the lower core 112 of the core unit 110 are coupled to each other in the vertical direction, a first accommodation space S1 (see FIG. 3) may be defined between the first outer leg portion OL1-1 and OL2-1 and the center leg portion CL1 and CL2, and a second accommodation space S2 may be defined between the second outer leg portion OL1-2 and OL2-2 and the center leg portion CL1 and CL2.
The first accommodation space S1 may be defined to accommodate an eleventh coil 131, a twelfth coil 133, and a second coil 132, which will be described later. The second accommodation space S2 may be defined to accommodate the eleventh coil 131, the twelfth coil 133, and the second coil 132, which will be described later.
Referring to FIG. 3, the bobbin unit 120 may include a first bobbin 121 and 125 and a second bobbin 123. The first bobbin 121 and 125 may include an eleventh bobbin 121 and a twelfth bobbin 125. The eleventh bobbin 121 may be disposed to be spaced apart from the twelfth bobbin 125 in the X-axis direction (i.e., the first direction or the short-axis direction) on a plane. The second bobbin 123 may be disposed between the eleventh bobbin 121 and the twelfth bobbin 125.
The eleventh bobbin 121, the second bobbin 123, and the twelfth bobbin 125 may include an eleventh through-hole TH11 (not shown), a second through-hole TH2 (not shown), and a twelfth through-hole TH12 (not shown) formed therein, respectively. The center leg portion CL1 and CL2 of the core unit 110 may penetrate the eleventh through-hole TH11, the first bobbin 121 may penetrate the second through-hole TH2, and the second bobbin 123 may be accommodated in the twelfth through-hole TH12.
Each of the eleventh bobbin 121, the second bobbin 123, and the twelfth bobbin 125 may have a long axis extending in the long-axis direction (i.e., the Y-axis direction or the second direction) in which the center leg portion CL1 and CL2 and the outer leg portions OL1-1 and OL2-1, and OL1-2 and OL2-2 extend on a plane, and may have a short axis extending from each of both ends of the long axis in the short-axis direction (i.e., the X-axis direction or the first direction) in which the center leg portion CL1 and CL2 and the outer leg portions OL1-1 and OL2-1, and OL1-2 and OL2-2 are spaced apart from each other on the plane.
For example, the eleventh bobbin 121 may include an eleventh sidewall 121p1, an eleventh upper plate 121p2 disposed at the upper end of the eleventh sidewall 121p1, and an eleventh lower plate 121p3 disposed at the lower end of the eleventh sidewall 121p1. That is, the eleventh bobbin 121 may include an eleventh accommodation portion 122 defined by the eleventh sidewall 121p1, the eleventh upper plate 121p2, and the eleventh lower plate 121p3. The eleventh accommodation portion 122 may accommodate the eleventh coil 131.
The eleventh sidewall 121p1 may have a rectangular planar shape with rounded corners, and the eleventh upper plate 121p2 or the eleventh lower plate 121p3 may have a rectangular ring-shaped planar shape with rounded corners. However, the disclosure is not necessarily limited thereto.
The eleventh sidewall 121p1 may insulate the center leg portion CL1 and CL2 from the eleventh coil 131 included in the first coil 131 and 133. In addition, the inner circumferential surface of the eleventh sidewall 121p1 may define the eleventh through-hole TH11, and the eleventh coil 131 may be wound around the outer circumferential surface of the eleventh sidewall 121p1. A detailed description of the coil will be provided later.
The eleventh upper plate 121p2 may insulate the upper core 111 from the eleventh coil 131, and the eleventh lower plate 121p3 may insulate the lower core 112 from the eleventh coil 131 and may support the eleventh coil 131 upward.
The second bobbin 123 may include a second sidewall 123p1, a second upper plate 123p2 disposed at the upper end of the second sidewall 123p1, and a second lower plate 123p3 disposed at the lower end of the second sidewall 123p1. That is, the second bobbin 123 may include a second accommodation portion 124 defined by the second sidewall 123p1, the second upper plate 123p2, and the second lower plate 123p3. The second accommodation portion 124 may accommodate the second coil 132.
The second sidewall 123p1 may have a rectangular planar shape with rounded corners, and the second upper plate 123p2 or the second lower plate 123p3 may have a rectangular ring-shaped planar shape with rounded corners. However, the disclosure is not necessarily limited thereto.
The second sidewall 123p1 may insulate the eleventh coil 131 from the second coil 132. In addition, the inner circumferential surface of the second sidewall 123p1 may define the second through-hole TH2, and the second coil 132 may be wound around the outer circumferential surface of the second sidewall 123p1. A detailed description of the coil will be provided later.
The second upper plate 123p2 may insulate the upper core 111 from the second coil 132, and the second lower plate 123p3 may insulate the lower core 112 from the second coil 132 and may support the second coil 132 upward.
The twelfth bobbin 125 may include a twelfth sidewall 125p1, a twelfth upper plate 125p2 disposed at the upper end of the twelfth sidewall 125p1, and a twelfth lower plate 125p3 disposed at the lower end of the twelfth sidewall 125p1. That is, the twelfth bobbin 125 may include a twelfth accommodation portion 126 defined by the twelfth sidewall 125p1, the twelfth upper plate 125p2, and the twelfth lower plate 125p3. The twelfth accommodation portion 126 may accommodate the twelfth coil 133.
The twelfth sidewall 125p1 may have a rectangular planar shape with rounded corners, and the twelfth upper plate 125p2 or the twelfth lower plate 125p3 may have a rectangular ring-shaped planar shape with rounded corners. However, the disclosure is not necessarily limited thereto.
The twelfth sidewall 125p1 may insulate the second coil 132 from the twelfth coil 133 included in the first coil 131 and 133. In addition, the inner circumferential surface of the twelfth sidewall 125p1 may define the twelfth through-hole TH12, and the twelfth coil 133 may be wound around the outer circumferential surface of the twelfth sidewall 125p1. A detailed description of the coil will be provided later.
The twelfth upper plate 125p2 may insulate the upper core 111 from the twelfth coil 133, and the twelfth lower plate 125p3 may insulate the lower core 112 from the twelfth coil 133 and may support the twelfth coil 133 upward.
The twelfth bobbin 125 may include a first pin 115, 116, and 117 conductively connected to the first coil 131 and 133 and a second pin 118 conductively connected to the second coil 132. A detailed description thereof will be provided later.
In addition, although each of the eleventh bobbin 121, the second bobbin 123, and the twelfth bobbin 125 has been described above as including a through-hole formed therein, the disclosure is not limited thereto.
The coil unit 130 may be a multi-turn winding in which a rigid conductive metal, for example, a copper wire, is wound in multiple turns. However, the disclosure is not necessarily limited thereto. The coil unit 130 may include a first coil 131 and 133 and a second coil 132.
The first coil 131 and 132 may include an eleventh coil 131 and a twelfth coil 133. The eleventh coil 131 and the twelfth coil 133 may be disposed to be spaced apart from each other in the X-axis direction (i.e., the first direction or the short-axis direction) on a plane.
The second coil 132 may be disposed between the eleventh coil 131 and the twelfth coil 133, which are spaced apart from each other.
Accordingly, the eleventh coil 131 may be disposed closer to the center leg portion CL1 and CL2 than the second coil 132, and the second coil 132 may be disposed closer to the center leg portion CL1 and CL2 than the twelfth coil 133.
The thickness of the conductive wire forming the second coil 132 may be 50% to 150% of the thickness of the conductive wire forming each of the eleventh coil 131 and the twelfth coil 133. However, the disclosure is not necessarily limited thereto.
In addition, in the transformer 100 according to the embodiment, the eleventh coil 131 and the twelfth coil 133 may correspond to a primary coil, and the second coil 132 may correspond to a secondary coil. However, the disclosure is not necessarily limited thereto.
In addition, the first pin 115, 116, and 117, which is an end of the conductive wire forming the first coil 131 and 133, and the second pin 118, which is an end of the conductive wire forming the second coil 132, may be disposed in the twelfth bobbin 125 and may be drawn out in directions opposite each other with respect to the twelfth bobbin 125. However, such drawing-out directions are merely exemplary, and the disclosure is not necessarily limited thereto.
For example, the first pin 115, 116, and 117 may be conductively connected to the first coil 131 and 133 and may include an eleventh pin 115, a twelfth pin 116, and a thirteenth pin 117.
The eleventh pin 115 may be conductively connected to the eleventh coil 131, the twelfth pin 116 may be conductively connected to the twelfth coil 133, and the thirteenth pin 117 may be conductively connected to the eleventh coil 131 and the twelfth coil 133. The eleventh pin 115, the twelfth pin 116, and the thirteenth pin 117 may be disposed to be spaced apart from each other in the X-axis direction (or the first direction) on a plane.
Although the configuration in which the eleventh pin 115, the twelfth pin 116, and the thirteenth pin 117 are disposed has been described, the disclosure is not limited thereto.
The second pin 118 may be conductively connected to the second coil 132. One or more second pins 118 may be disposed in the twelfth bobbin 125. One or more second pins 118 may be disposed to be spaced apart from each other in the X-axis direction (or the first direction) on a plane. However, the disclosure is not limited thereto.
Referring to FIG. 4, the eleventh coil, the twelfth coil, and the second coil according to the embodiment of the present disclosure may be formed to have predetermined widths.
The eleventh coil 131 may have an eleventh width W1. The eleventh width W1 may be a width or length of the eleventh coil 131 wound on the eleventh bobbin 121 measured in the X-axis direction (or the first direction). That is, the eleventh width W1 may be a maximum width of the eleventh coils 131 in the X-axis direction wound on the eleventh bobbin 121 in the X-axis direction (or the first direction).
The second coil 132 may have a second width W2. The second width W2 may be a width or length of the second coil 132 wound on the second bobbin 123 measured in the X-axis direction (or the first direction). That is, the second width W2 may be a maximum width of the second coils 132 in the X-axis direction wound on the second bobbin 123 in the X-axis direction (or the first direction).
The twelfth coil 133 may have a twelfth width W3. The twelfth width W3 may be a width or length of the twelfth coil 133 wound on the twelfth bobbin 125 measured in the X-axis direction (or the first direction). That is, the twelfth width W3 may be a maximum width of the twelfth coils 133 in the X-axis direction wound on the twelfth bobbin 125 in the X-axis direction (or the first direction).
The second width W2, which is the width of the second coil 132 measured in the X-axis direction (or the first direction), may be greater than the eleventh width W1, which is the width of the eleventh coil 131 measured in the X-axis direction (or the first direction), or the twelfth width W3, which is the width of the twelfth coil 133 measured in the X-axis direction (or the first direction).
The second width W2, which is the width of the second coil 132 measured in the X-axis direction (or the first direction), may be less than the sum of the eleventh width W1, which is the width of the eleventh coil 131 measured in the X-axis direction (or the first direction), and the twelfth width W3, which is the width of the twelfth coil 133 measured in the X-axis direction (or the first direction).
As described above, the present disclosure may prevent deterioration in coil coupling efficiency by forming the sum of the eleventh width W1 and the twelfth width W3 to be greater than the second width W2, thereby obtaining a relatively regular magnetic field value.
In addition, the present disclosure may reduce the leakage inductance value by forming the sum of the eleventh width W1 and the twelfth width W3 to be greater than the second width W2.
Referring to FIG. 5, the second coil 132 according to the embodiment of the present disclosure may be spaced apart from the eleventh coil 131 and the twelfth coil 133.
For example, the maximum distance by which the second coil 132 is spaced apart from the eleventh coil 131 in the X-axis direction (or the first direction) may be a first distance D1. The first distance D1 may be referred to as a first interval or a first spacing distance.
The maximum distance by which the second coil 132 is spaced apart from the twelfth coil 133 in the X-axis direction (or the first direction) may be a second distance D2. The second distance D2 may be referred to as a second interval or a second spacing distance.
The sum of the first distance D1 and the second distance D2 may be a constant spacing distance. For example, the sum of the first distance D1 and the second distance D2 may be 7% to 15% of the distance between the center leg portion and one of the first outer leg portion and the second outer leg portion.
In this case, if the sum of the first distance D1 and the second distance D2 is less than 7% of the distance between the center leg portion and one of the first outer leg portion and the second outer leg portion, an LLC mismatch in the PSU circuit board may cause an increase in the operating frequency, which may result in irregular magnetic field values, thereby making control of the board impossible. If the sum exceeds 15%, a decrease in coil coupling efficiency may result in irregular and elevated magnetic field values, which may in turn increase the overall loss of components.
In addition, referring to FIG. 5, the eleventh coil 131, the twelfth coil 133, and the second coil 132 according to the embodiment of the present disclosure may be formed to have predetermined heights.
The eleventh coil 131 may have an eleventh height H1. The eleventh height H1 may be a height or thickness of the eleventh coil 131 wound on the eleventh bobbin 121 measured in the Z-axis direction (or the third direction). That is, the eleventh height H1 may be a maximum thickness of the eleventh coils 131 in the Z-axis direction wound on the eleventh bobbin 121 in the Z-axis direction (or the third direction).
The second coil 132 may have a second height H2. The second height H2 may be a height or thickness of the second coil 132 wound on the second bobbin 123 measured in the Z-axis direction (or the third direction). That is, the second height H2 may be a maximum thickness of the second coils 132 in the Z-axis direction wound on the second bobbin 123 in the Z-axis direction (or the third direction).
The twelfth coil 133 may have a twelfth height H3. The twelfth height H3 may be a height or thickness of the twelfth coil 133 wound on the twelfth bobbin 125 measured in the Z-axis direction (or the third direction). That is, the twelfth height H3 may be a maximum thickness of the twelfth coils 133 in the Z-axis direction wound on the twelfth bobbin 125 in the Z-axis direction (or the third direction).
The second height H2, which is the height of the second coil 132 measured in the Z-axis direction (or the third direction), may be greater than the eleventh height H1, which is the height of the eleventh coil 131 measured in the Z-axis direction (or the third direction), or the twelfth height H3, which is the height of the twelfth coil 133 measured in the Z-axis direction (or the third direction).
The second height H2, which is the height of the second coil 132 measured in the Z-axis direction (or the third direction), may be less than the sum of the eleventh height H1, which is the height of the eleventh coil 131 measured in the Z-axis direction (or the third direction), and the twelfth height H3, which is the height of the twelfth coil 133 measured in the Z-axis direction (or the third direction).
As described above, the present disclosure may prevent deterioration in coil coupling efficiency by forming the sum of the eleventh height H1 and the twelfth height H3 to be greater than the second height H2, thereby obtaining a relatively regular magnetic field value.
In addition, the present disclosure may reduce the leakage inductance value by forming the sum of the eleventh height H1 and the twelfth height H3 to be greater than the second height H2.
In the transformer 100 according to FIGs. 1 to 5 described above, the eleventh coil 131 and the twelfth coil 133, which correspond to the primary coil, may be formed with a first number of turns α and a second number of turns β, respectively.
The first number of turns α and the second number of turns β have a relationship shown in Equation 1 and Table 1 below. As shown in Table 1, the sum of the first number of turns α and the second number of turns may be constant. FIG. 6 is a graph showing the data of Table 1.

$α / (α + β) * 100 % \geq 50 %$
α represents the first number of turns of the coil adjacent to the center leg region, and β represents the second number of turns of the coil adjacent to the outer leg region.
Equation 1 may indicate that the first number of turns α is greater than or equal to the second number of turns β. That is, the more the number of turns of the coil adjacent to the center leg region is increased compared to the number of turns of the coil adjacent to the outer leg region, the lower the coil loss may be. [Table 1]

First Number of Turns Second Number of Turns Total Number of Turns Coil-loss [W]

0 12 12 42.6

2 10 12 37.6

4 8 12 33.2

6 6 12 29.5

8 4 12 26.7

10 2 12 24.7

12 0 12 23.5
Table 1 and the graph of FIG. 6 illustrate variations in coil loss resulting from an increase in the first number of turns of the eleventh coil, under the condition that the number of turns of the twelfth coil remains constant. Because the twelfth coil 133 is disposed farther from the center leg portion CL1 and CL2 than the eleventh coil 131, DCR (resistance) thereof may be higher even when the number of turns thereof is equal to that of the eleventh coil. In addition, it may be seen that coil loss increases as the second number of turns of the twelfth coil 133 increases.
Therefore, in the present disclosure, the first number of turns α of the eleventh coil 131 adjacent to the center leg region may be equal to or greater than the second number of turns β of the twelfth coil 133 adjacent to the outer leg region.
As described above, the present disclosure may maintain a constant magnetic field value in the magnetic component by dividing the first coil 131 and 133, which is the primary coil, into the eleventh coil 131 and the twelfth coil 133.
In addition, the present disclosure may keep the leakage inductance value low by dividing the first coil 131 and 133, which is the primary coil, into the eleventh coil 131 and the twelfth coil 133 and setting the first number of turns of the eleventh coil 131 to be equal to or greater than the second number of turns of the twelfth coil 133.
As the first distance D1, which is a spacing distance, increases, the leakage inductance value increases. In the conventional transformer winding structure in which the first coil is not divided, coil coupling efficiency may deteriorate because the distance between the first coil and the second coil exceeds the predetermined spacing distance D1. As a result, irregular and high magnetic field values may occur, which may increase the overall loss of the component.
The present disclosure may maintain a constant magnetic field value in the magnetic component by dividing the first coil, which is the primary coil, into the eleventh coil and the twelfth coil.
In addition, the present disclosure may keep the leakage inductance value low by dividing the first coil, which is the primary coil, into the eleventh coil and the twelfth coil and setting the first number of turns of the eleventh coil to be equal to or greater than the second number of turns of the twelfth coil.
FIG. 7 is a cross-sectional view of a transformer according to another embodiment of the present disclosure.
In FIG. 7, descriptions of the core unit 110 and the coil unit 130 identical to those described with reference to FIGs. 1 to 6 will be omitted.
The bobbin unit 220 may include a first bobbin 221 and 225 and a second bobbin 223. The first bobbin 221 and 225 may include an eleventh bobbin 221 and a twelfth bobbin 225.
Although not shown, the eleventh bobbin 221, the twelfth bobbin 225, and the second bobbin 223 may include an eleventh through-hole, a second through-hole, and a twelfth through-hole formed therein, respectively. This configuration has been sufficiently described above, and thus further description thereof will be omitted.
Each of the eleventh bobbin 221, the twelfth bobbin 225, and the second bobbin 223 may have a long axis extending in the long-axis direction (i.e., the Y-axis direction or the second direction) in which the center leg portion CL1 and CL2 and the outer leg portions OL1-1 and OL2-1, and OL1-2 and OL2-2 extend on a plane, and may have a short axis extending from each of both ends of the long axis in the short-axis direction (i.e., the X-axis direction or the first direction) in which the center leg portion CL1 and CL2 and the outer leg portions OL1-1 and OL2-1, and OL1-2 and OL2-2 are spaced apart from each other on the plane.
For example, the first bobbin 221 may include an eleventh sidewall and an eleventh lower plate disposed at the lower end of the eleventh sidewall.
The eleventh sidewall may have a rectangular planar shape with rounded corners, and the eleventh lower plate may have a rectangular ring-shaped planar shape with rounded corners. However, the disclosure is not necessarily limited thereto.
The eleventh sidewall may insulate the center leg portion CL1 and CL2 from the eleventh coil 131. In addition, the inner circumferential surface of the eleventh sidewall may define the eleventh through-hole, and the eleventh coil 131 may be wound around the outer circumferential surface of the eleventh sidewall.
The eleventh lower plate may insulate the lower core 112 from the eleventh coil 131 and may support the eleventh coil 131 upward.
The second bobbin 223 may include a second sidewall and a second lower plate disposed at the lower end of the second sidewall.
The second sidewall may have a rectangular planar shape with rounded corners, and the second lower plate may have a rectangular ring-shaped planar shape with rounded corners. However, the disclosure is not necessarily limited thereto.
The second sidewall may insulate the eleventh coil 131 from the second coil 132. In addition, the inner circumferential surface of the second sidewall may define the second through-hole, and the second coil 132 may be wound around the outer circumferential surface of the second sidewall.
The second lower plate may insulate the lower core 112 from the second coil 132 and may support the second coil 132 upward.
The twelfth bobbin 225 may include a twelfth sidewall and a twelfth lower plate disposed at the lower end of the twelfth sidewall.
The twelfth sidewall may have a rectangular planar shape with rounded corners, and the third lower plate may have a rectangular ring-shaped planar shape with rounded corners. However, the disclosure is not necessarily limited thereto.
The twelfth sidewall may insulate the second coil 132 from the twelfth coil 133. In addition, the inner circumferential surface of the twelfth sidewall may define the twelfth through-hole TH3, and the twelfth coil 133 may be wound around the outer circumferential surface of the twelfth sidewall.
The twelfth lower plate may insulate the lower core 112 from the twelfth coil 133 and may support the twelfth coil 133 upward.
As described above, according to the other embodiment of the present disclosure, each of the eleventh bobbin 221, the twelfth bobbin 225, and the second bobbin 223 includes only the sidewall and the lower plate without the upper plate, thereby not only facilitating slimming compared to the conventional transformer, but also maintaining a constant magnetic field value in the magnetic component by dividing the first coil, which is the primary coil, into the eleventh coil and the twelfth coil.
In addition, the present disclosure may keep the leakage inductance value low by dividing the first coil, which is the primary coil, into the eleventh coil and the twelfth coil and setting the first number of turns of the eleventh coil to be greater than the second number of turns of the twelfth coil.
FIG. 8 is a cross-sectional view of a transformer according to still another embodiment of the present disclosure, and FIG. 9 is an enlarged view of portion A in FIG. 8.
In FIGs. 8 and 9, a description of the core unit 110 identical to that described with reference to FIGs. 1 to 6 will be omitted.
The coil unit 230 may be a multi-turn winding in which a rigid conductive metal, for example, a copper wire, is wound in multiple turns. However, the disclosure is not necessarily limited thereto. The coil unit 230 may include a first coil 231 and 233 and a second coil 232.
The first coil 231 and 233 may include an eleventh coil 231 and a twelfth coil 233. The eleventh coil 231 and the twelfth coil 233 may be disposed to be spaced apart from each other in the X-axis direction (i.e., the first direction or the short-axis direction) on a plane.
Each of the eleventh coil 231 and the twelfth coil 233 may be coated to enhance insulation properties thereof. That is, each of the eleventh coil 231 and the twelfth coil 233 may be formed as a coil having a surface to which primary insulation processing is applied, followed by secondary insulation adhesion processing.
For example, as shown in FIG. 9, an insulating coating layer 231a may be formed on the surface of the eleventh coil 231 with a predetermined thickness. The coils may then be bonded to each other by an insulating adhesive 231b.
Although not shown in FIG. 9, the twelfth coil 233, which has substantially the same configuration as the eleventh coil 231, may have an insulating coating layer 233a formed on the surface thereof with a predetermined thickness. The coils may be bonded to each other by an insulating adhesive (not shown) .
As described above, since each of the eleventh coil 231 and the twelfth coil 233 is reinforced in insulation properties by the insulating coating layer and the insulating adhesive, the bobbin for insulating the first coil 231 and 233 and the second coil 232 from each other may be omitted.
Accordingly, within the accommodation space in the core unit, the space occupied by the bobbin may be filled with the eleventh coil 231 and the twelfth coil 233.
The second coil 232 may be disposed between the eleventh coil 231 and the twelfth coil 233, which are spaced apart from each other. Accordingly, the eleventh coil 231 may be disposed closer to the center leg portion CL1 and CL2 than the second coil 232, and the second coil 232 may be disposed closer to the center leg portion CL1 and CL2 than the twelfth coil 233.
In addition, the second coil 232 may also be coated to enhance insulation properties thereof. The second coil 132 may be formed as a coil having a surface to which primary insulation processing is applied, followed by secondary insulation adhesion processing. Although not shown, an insulating coating layer may be formed on the surface of the second coil 232 with a predetermined thickness. The coils may then be bonded to each other by an insulating adhesive.
In this case, when the second coil 232 is formed with enhanced insulation properties, insulation reinforcing coating may not be applied to the eleventh coil 231 and the twelfth coil 233. Since the second coil 232 is disposed between the eleventh coil 231 and the twelfth coil 233, forming the second coil 232 with enhanced insulation properties may allow insulation between the eleventh coil 231 and the second coil 232 and between the second coil 232 and the twelfth coil 233.
While the present disclosure has been particularly shown and described with reference to exemplary embodiments thereof, these embodiments are only proposed for illustrative purposes, and do not restrict the present disclosure, and it will be apparent to those skilled in the art that various changes in form and detail may be made without departing from the essential characteristics of the embodiments set forth herein. For example, respective configurations set forth in the embodiments may be modified and applied. Further, differences in such modifications and applications should be construed as falling within the scope of the present disclosure as defined by the appended claims.

[Mode for Disclosure]

Various embodiments have been described in the best mode for carrying out the disclosure, and thus descriptions thereof will be omitted.

Claims

A transformer, comprising:
a core unit including an upper core and a lower core; and

a coil unit including a primary coil and a secondary coil, a portion of the coil unit being disposed inside the core unit,

wherein the primary coil includes an eleventh coil and a twelfth coil disposed to be spaced apart from each other in a first direction on a plane, and

wherein the secondary coil is disposed between the eleventh coil and the twelfth coil.
The transformer according to claim 1, further comprising a bobbin unit disposed between the primary coil and the secondary coil.
The transformer according to claim 2, wherein the bobbin unit includes:
a first bobbin configured to accommodate the primary coil; and

a second bobbin including a second accommodation portion formed therein to accommodate the secondary coil,

wherein the first bobbin includes:
an eleventh bobbin including an eleventh accommodation portion formed therein to accommodate the eleventh coil; and

a twelfth bobbin disposed to be spaced apart from the eleventh bobbin in the first direction, the twelfth bobbin including a twelfth accommodation portion formed therein to accommodate the twelfth coil, and

wherein the second bobbin is disposed between the eleventh bobbin and the twelfth bobbin.
The transformer according to claim 3, wherein the twelfth bobbin includes a first pin conductively connected to the first coil, and
wherein the first pin includes:
an eleventh pin conductively connected to the eleventh coil;

a twelfth pin conductively connected to the twelfth coil; and

a thirteenth pin conductively connected to the eleventh coil and the twelfth coil.
The transformer according to claim 3, wherein a width of the secondary coil in the first direction is less than a sum of a width of the eleventh coil in the first direction and a width of the twelfth coil in the first direction.
The transformer according to claim 3, wherein a height of the secondary coil in a third direction intersecting the first direction is less than a sum of a height of the eleventh coil in the third direction and a height of the twelfth coil in the third direction.
The transformer according to claim 3, wherein the core unit includes:
a first outer leg portion;

a second outer leg portion;

a center leg portion disposed between the first outer leg portion and the second outer leg portion;

a first accommodation space defined between the first outer leg portion and the center leg portion to accommodate the eleventh coil, the secondary coil, and the twelfth coil; and

a second accommodation space defined between the second outer leg portion and the center leg portion to accommodate the eleventh coil, the secondary coil, and the twelfth coil,

wherein the eleventh coil is disposed closer to the center leg portion than the secondary coil, and

wherein the secondary coil is disposed closer to the center leg portion than the twelfth coil.
The transformer according to claim 7, wherein a number of turns (α) of the eleventh coil and a number of turns (β) of the twelfth coil satisfy Equation 1 below: $α / (α + β) * 100 % \geq 50 % .$
The transformer according to claim 7, wherein a sum of a maximum spacing distance between the secondary coil and the eleventh coil and a maximum spacing distance between the secondary coil and the twelfth coil is 7% to 15% of a distance between the center leg portion and one of the first outer leg portion and the second outer leg portion.
A circuit board, comprising the transformer described in any one of claims 1 to 9.