CN116762146A

CN116762146A - transformer

Info

Publication number: CN116762146A
Application number: CN202280011184.4A
Authority: CN
Inventors: 俞瑄煐; 裵硕; 孙寅性
Original assignee: LG Innotek Co Ltd
Current assignee: LG Innotek Co Ltd
Priority date: 2021-01-22
Filing date: 2022-01-20
Publication date: 2023-09-15
Also published as: KR20220111029A

Abstract

A transformer according to one embodiment includes: a core; and a first coil part and a second coil part, at least a portion of which are received in the core, wherein the second coil part has a plurality of wires intersecting each other in a specific region, so that an inductance deviation between the wires can be reduced, and the first coil of the first coil part can be provided with terminals through the terminal bobbin.

Description

Transformer

Technical Field

The present disclosure relates to a transformer.

Background

Various coil parts (e.g., transformers or line filters) are installed in a power supply unit of an electronic device.

Transformers may be included in electronic devices for various purposes. For example, a transformer may be used to perform an energy transfer function that transfers energy from one circuit to another. In addition, a transformer may be used to perform a step-up or step-down function that changes the voltage magnitude. Furthermore, the transformer has the property of exhibiting only inductive coupling (inductive coupling) between the primary and secondary windings and thus not directly forming a DC path, and can be used for blocking direct current and applying alternating current, or for insulation between two circuits.

Fig. 1 is an exploded perspective view showing an example of the construction of a general transformer.

Referring to fig. 1, a general thin type transformer 10 includes a core unit including an upper core 11 and a lower core 12, and includes a secondary coil 13 and a primary coil 14 disposed between the cores 11 and 12. Typically, the secondary coil 13 is composed of a plurality of conductive metal plates, and the primary coil 14 takes the form of a wound wire. In another configuration, a coil former (not shown) may be provided between the upper core 11 and the lower core 12.

In the transformer shown in fig. 1, the primary coil and the secondary coil overlap each other in the vertical direction. When a wire is used for the secondary coil instead of the conductive metal plate, the primary coil and the secondary coil may be disposed to overlap each other in the horizontal direction.

However, when the wires are used for the secondary coil, in order to achieve the thinning, it is necessary to arrange the wires in parallel with each other when seen in a plan view, so that turns are formed around a center leg (leg) of the core unit. In this case, the inner wire closest to the center pillar is shortest, and the outer wire furthest from the center pillar is longest, whereby inductance change occurs. This change in inductance results in a concentration of current, and the concentration of current results in intense heat generation.

Disclosure of Invention

Technical problem

The technical task of the present disclosure is to provide a transformer having a slim structure capable of reducing heat generation and preventing heat generation due to inductance variation caused by a length difference between wires constituting a coil.

Another technical task of the present disclosure is to provide a thin type transformer capable of further thinning and securing leakage inductance (leakage inductance).

The technical tasks of the present disclosure are not limited to the above technical tasks, and other technical tasks not mentioned herein will be clearly understood by those skilled in the art from the following description.

Technical proposal

The transformer according to an embodiment includes: a core unit including an upper core and a lower core; a coil unit partially disposed in the core unit; and a bobbin unit disposed between the core unit and the bobbin unit, wherein the bobbin unit includes a first coil and a second coil disposed at least partially beside the first coil, wherein the bobbin unit includes a first bobbin having a first receiving portion formed therein to receive the first coil and a second bobbin having a second receiving portion formed therein to receive the second coil, wherein the first bobbin includes a first extending portion extending from the first receiving portion toward the second bobbin, and wherein the second receiving portion is disposed on the first extending portion.

The first bobbin may include a first top portion, a first bottom portion disposed below the first top portion, and a first intermediate portion disposed between the first top portion and the bottom portion, the first intermediate portion having a first through hole defined by an inner side surface thereof. The first extension portion may be disposed on the first bottom portion.

The second bobbin may include a second top portion having a second through hole formed at a central portion thereof, a second bottom portion disposed below the second top portion, and a second intermediate portion disposed between the second top portion and the second bottom portion. The first bobbin may be at least partially received in a recess defined by a lower surface of the second top portion and an inner side surface of the second intermediate portion.

The first extension portion may face a lower surface of the second bottom portion.

The second top portion may include a first guide and a second guide facing each other in a long axis direction of the second bobbin (with the second through hole interposed therebetween), and each of the first guide and the second guide may protrude upward from an upper surface of the second top portion and may extend in a short axis direction of the second bobbin.

The upper core may be disposed between the first guide and the second guide.

The second top portion may further include a third through hole facing the second through hole in the long axis direction, the second guide being interposed between the second through hole and the third through hole.

The first top portion may further include a coil lead-out portion disposed on an upper surface thereof, and the coil lead-out portion may pass through the third through hole to be exposed.

The second top portion may further include a blind hole formed in a lower surface thereof so as to extend to an inside of the second guide, and the first top portion may further include a protruding pin disposed between the coil lead-out portion and the first through hole and protruding upward from an upper surface thereof so as to be inserted into the blind hole.

The shortest distance from the lower surface of the lower core to the first coil and the shortest distance from the lower surface of the lower core to the second coil may be different from each other.

The shortest distance from the lower surface of the lower core to the first coil may be shorter than the shortest distance from the lower surface of the lower core to the second coil.

The second bobbin may include a second extension portion extending from the second receiving portion toward the first bobbin, and the first receiving portion may be disposed under the second extension portion.

A portion of the second receiving portion may be disposed between the first coil and the second coil.

The core unit may include a first outer leg portion, a second outer leg portion, and a central leg portion disposed between the first outer leg portion and the second outer leg portion, and a shortest distance between the first coil and the second coil may be 0.1 to 0.3 times a shortest distance from an outermost periphery of the first coil to one outer leg portion adjacent to the outermost periphery of the first coil among the first outer leg portion and the second outer leg portion.

The core unit may further include a first space defined between the first outer leg portion and the central leg portion to receive a portion of the bobbin unit, and a second space defined between the second outer leg portion and the central leg portion to receive another portion of the bobbin unit.

The ratio of the second distance (shortest distance between the first coil and the second coil in the first space or the second space) to the first distance (shortest distance between the first coil and the second coil in the region outside the first space and the second space) may be 1 to 1.3.

The shortest distance from the lower surface of the lower core to the first coil may be 0.3 to 0.7 times the shortest distance from the lower surface of the lower core to the second coil.

A flat panel display device according to another embodiment includes a power supply unit in which a transformer is disposed, wherein the transformer includes: a core unit including an upper core and a lower core; a coil unit partially disposed in the core unit; and a bobbin unit disposed between the core unit and the bobbin unit, wherein the bobbin unit includes a first coil and a second coil disposed at least partially beside the first coil, wherein the bobbin unit includes a first bobbin having a first receiving portion formed therein to receive the first coil and a second bobbin having a second receiving portion formed therein to receive the second coil, wherein the first bobbin includes a first extending portion extending from the first receiving portion to the second bobbin, and wherein the second receiving portion is disposed on the first extending portion.

A transformer according to still another embodiment includes: a core unit including an upper core and a lower core; a first coil unit and a second coil unit disposed at least partially between the upper core and the lower core; and a terminal bobbin connected to one side of the second coil unit in a first direction, wherein the first coil unit includes a first coil and a first bobbin having a first through hole through which a center pillar of the core unit passes, the first bobbin receiving the first coil, wherein the second coil unit includes a second coil and a second bobbin having a second through hole receiving at least a portion of the first coil unit, the second bobbin receiving the second coil, wherein the terminal bobbin includes a plurality of first terminals and openings, the plurality of first terminals being spaced apart from each other in a second direction crossing the first direction on one side of the terminal bobbin oriented in the first direction, the openings being formed on the other side opposite to the one side in the first direction to allow one side of the second coil unit to be inserted therein, and wherein both ends of the first coil are drawn out from the first bobbin and are connected to first terminals different from each other among the plurality of first terminals of the terminal bobbin, respectively.

The first coil carrier may include a first top plate, a bottom plate spaced apart from the first top plate in a third direction intersecting the first direction and the second direction, and a first sidewall disposed between the top plate and the bottom plate. The first top plate may include a lead-out hole (lead-out hole) allowing both ends to be led out to the first top plate through the lead-out hole.

The terminal bobbin may include a recess formed at the other side thereof oriented in the first direction, and the recess may overlap the lead-out groove in the third direction.

The terminal bobbin may include a plurality of first wire guides that extend from the recess toward the plurality of first terminals, respectively, and both end portions of the first coil may be drawn out through the drawing groove, and may extend to the corresponding first terminals along respective different ones of the plurality of first wire guides.

The second bobbin may include a second top plate, a second bottom plate spaced apart from the second top plate in a third direction intersecting the first direction and the second direction, and a second sidewall disposed between the second top plate and the second bottom plate.

The transformer may include a first portion disposed on one side of the second bobbin in the first direction with respect to the second through hole, and a second portion disposed on the other side opposite to the first portion with respect to the second through hole. The second coil may include a plurality of wires disposed around the second via. One side of the plurality of wires may extend to be disposed on the second portion, and the other side of the plurality of wires may extend such that both ends of the other side of the plurality of wires are disposed on the first portion. A first wire and a second wire among the plurality of wires at least partially overlap each other on the second portion. The second bobbin may include a recess at least partially overlapping a region where the first wire and the second wire of the second portion overlap each other in the third direction.

The recess may be formed in the second bottom plate.

The second bobbin may further include a plurality of second terminals disposed on a second bottom plate in the first portion.

The first and second wires may have a symmetrical shape in the first direction with respect to the second through hole.

The plurality of wires may further include a third wire forming a turn outside the first wire when viewed in a plan view and a fourth wire forming a turn outside the second wire when viewed in a plan view.

The third wire and the first wire may be disposed in parallel to form turns, and the fourth wire and the second wire may be disposed in parallel to form turns.

The second top plate may include a first partition wall portion protruding in a third direction from an edge of the first portion oriented in the first direction and extending in the second direction.

The second bobbin may further include a second wire guide extending in the first direction between the second sidewall and the plurality of second terminals.

The second bobbin may further include a second partition wall portion protruding downward from the second bottom plate in the third direction between the second through hole and the recess, and extending in the second direction.

The second bobbin may further include a first support portion protruding from the second partition wall portion toward the second through hole in the first direction, the second support portion facing the first support portion (the second through hole interposed between the first support portion and the second support portion), and the first support portion and the second support portion may support the first coil unit.

A circuit board according to still another embodiment includes a substrate and a transformer disposed on the substrate, wherein the transformer includes: a core unit including an upper core and a lower core; a first coil unit and a second coil unit disposed at least partially between the upper core and the lower core; and a terminal bobbin coupled to one side of the second coil unit in a first direction, wherein the first coil unit includes a first coil and a first bobbin having a first through hole through which a center leg of the core unit passes, the first bobbin receiving the first coil, wherein the second coil unit includes a second coil and a second bobbin having a second through hole receiving at least a portion of the first coil unit, the second bobbin receiving the second coil, wherein the terminal bobbin includes a plurality of first terminals provided on one side of the terminal bobbin oriented in the first direction and spaced apart from each other in a second direction intersecting the first direction, and an opening formed on the other side opposite to the one side in the first direction to allow one side of the second coil unit to be inserted therein, and wherein both ends of the first coil are led out from the first bobbin and are connected to different first terminals among the plurality of first terminals of the terminal bobbin, respectively.

Advantageous effects

The transformer according to the embodiment is configured such that a plurality of wires constituting a coil intersect each other in one region, thereby minimizing a length difference between the wires.

In addition, the terminal pins are short-circuited with each other, thereby reducing inductance variation between the wires arranged in parallel constituting the same turn, and thus reducing heat generation.

Further, since the bobbin has an opening formed in a region where the wires intersect each other, slimness can be achieved.

In the transformer according to another embodiment, leakage inductance is ensured by controlling a separation distance between the first coil unit and the second coil unit.

Further, due to the coupling structure of the first bobbin and the second bobbin, an insulation distance is ensured between the primary coil and the core, whereby leakage inductance can be ensured.

The effects achievable by the present disclosure are not limited to the above-described effects, and other effects not mentioned herein will be clearly understood by those skilled in the art from the following description.

Drawings

Fig. 1 is an exploded perspective view showing an example of the construction of a general thin type transformer.

Fig. 2a is a plan view of a transformer according to an embodiment.

Fig. 2b is a bottom view of the transformer according to this embodiment.

Fig. 2c is a cross-sectional view of the transformer according to this embodiment taken along line A-A' in fig. 2 a.

Fig. 3a is a perspective view of a first bobbin according to an embodiment.

Fig. 3b is a plan view of the first bobbin according to this embodiment.

Fig. 4a is a plan view of a second bobbin according to an embodiment.

Fig. 4b is a perspective view of the second bobbin according to this embodiment.

Fig. 4c is a rear perspective view of the second bobbin according to this embodiment.

Fig. 5a is a plan view of a terminal bobbin according to an embodiment.

Fig. 5b is a perspective view of the terminal bobbin according to the embodiment.

Fig. 6 shows an example in which an adhesive portion of the transformer according to this embodiment is provided.

Fig. 7a shows an example of providing a coil of the second coil unit according to an embodiment.

Fig. 7b shows a pin diagram of the second coil unit according to an embodiment, and fig. 7c is a circuit diagram of the transformer according to an embodiment.

Fig. 7d is a view for explaining an overlapping pattern of wires on the second portion of the second coil unit according to the embodiment.

Fig. 7e is a rear view of the second coil unit according to the embodiment, and fig. 7f is a side view of the second coil unit according to the embodiment.

Fig. 7g is a plan view showing an example of the configuration of a second bobbin according to another embodiment.

Fig. 8a is a perspective view of a transformer according to yet another embodiment.

Fig. 8b is a plan view of a transformer according to yet another embodiment.

Fig. 9 is an exploded perspective view of a transformer according to yet another embodiment.

Fig. 10 is a perspective view of a first bobbin according to still another embodiment.

Fig. 11 is an exploded perspective view of a bobbin unit according to still another embodiment.

Fig. 12 is a cross-sectional view of a transformer according to yet another embodiment, taken along line B-B' in fig. 8B.

Fig. 13a is a cross-sectional view of a transformer according to yet another embodiment, taken along line A-A' in fig. 8 b.

Fig. 13b is an enlarged view of the portion C in fig. 13 a.

Fig. 14 shows an example of a circuit configuration of a power supply unit of an electronic product.

Detailed Description

The present disclosure now will be described more fully with reference to the accompanying drawings, in which various embodiments are shown. These examples, however, may take many different forms and should not be construed as limited to the embodiments set forth herein. The intention is to cover all modifications, equivalents, and alternatives falling within the scope and spirit of the disclosure.

Ordinal words including "second," "first," etc., may be used in describing various components, but they are not intended to limit the components. These expressions are merely used to distinguish one component from another. For example, a second element may be termed a first element, and, similarly, a first element may 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), region, pattern, or structure is referred to as being "on" or "under" another element (e.g., a substrate, layer (film), region, pad, or pattern), the term "on" or "under" means that the element is "directly on or under" the other element, or is "indirectly" formed, such that intervening elements may also be present. It should also be understood that the upper or lower standards are based on the figures. In addition, the thickness or size of layers (films), regions, patterns or structures shown in the drawings may be exaggerated, omitted or schematically drawn for clarity and convenience of explanation, and may not accurately reflect actual sizes.

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 is also intended to include the plural unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and "comprising," when used herein, specify the presence of stated features, integers, steps, operations, elements, components, or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof.

Unless otherwise defined, all terms (including technical or scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. Terms (e.g., terms defined in a general dictionary) should be construed to have the same meaning as terms in the context of the related art and should not be construed to have ideal or excessively formal meanings unless explicitly defined in the specification.

Hereinafter, a transformer according to an embodiment will be described in detail with reference to the accompanying drawings.

Fig. 2a is a plan view of a transformer according to an embodiment, fig. 2b is a rear view of the transformer according to the embodiment, and fig. 2c is a sectional view of the transformer according to the embodiment taken along line A-A' in fig. 2 a.

Referring to fig. 2a to 2c, the transformer 100 according to the embodiment may include core units 111 and 112, a first coil unit 120, a second coil unit 130, a terminal bobbin 140, and a core fixing unit 150. Hereinafter, each component will be described in detail.

The core units 111 and 112 may have a function of a magnetic circuit, and thus may serve as a path of magnetic flux. The core units 111 and 112 may include an upper core 111 disposed at an upper position and a lower core 112 disposed at a lower position. The two cores 111 and 112 may be formed to be symmetrical or asymmetrical to each other in the vertical direction. However, for convenience of explanation, description will be made on the assumption that two cores are formed to be vertically symmetrical to each other.

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 pillar portions protruding from the body portion in a thickness direction (i.e., a third axis direction) and extending in a predetermined direction. The plurality of pillar portions may include two outer pillars extending in one axial direction (herein, a first axial direction) and spaced apart from each other in the other axial direction (herein, a second axial direction), and one center pillar CL disposed between the two outer pillars when viewed in plan view.

When the upper core 111 and the lower core 112 are coupled to each other in the vertical direction, each of the outer struts and the center struts of the upper core 111 faces a corresponding one of the outer struts and the center struts of the lower core 112. In this case, a gap having a predetermined distance (for example, 10 μm to 200 μm, but not necessarily limited thereto) may be formed between at least one of the pair of outer struts and the pair of center struts facing each other. The size of the gap may be a space defined between the upper core 111 and the lower core 112 spaced apart from each other, and the gap may be filled with air (i.e., an air gap), or may be filled with an adhesive material.

Further, the core units 111 and 112 may include a magnetic material (e.g., iron or ferrite), but the present disclosure is not necessarily limited thereto.

The first coil unit 120 may include a first bobbin B1 and a first coil C1, the first bobbin B1 having a first through hole CH1 (or a first cavity) formed at a center thereof, the first coil C1 being wound around the first through hole CH1 in a receiving space of the first bobbin to form a plurality of turns.

The second coil unit 130 may include a second bobbin B2 and a second coil C2, the second bobbin B2 having a second through hole CH2 (refer to fig. 4 a) (or a second cavity) formed at the center thereof, the second coil C2 being disposed around the second through hole CH2 in a receiving space of the second bobbin B2 to form a coil turn. Here, at least a portion of the first coil unit 120 may be disposed in the second through hole CH 2. Accordingly, at least a portion of the first coil unit 120 and at least a portion of the second coil unit 130 may overlap each other in the first axis direction and the second axis direction. Each of the first coil C1 and the second coil C2 may be a multi-turn winding in which a rigid metal (e.g., copper wire) is wound a plurality of times in a spiral or planar spiral shape, but the present disclosure is not necessarily limited thereto. For example, an enamel wire (USTC wire), litz (Litz) wire, three-layer insulated wire (TIW) wound with a fiber yarn, or the like may be used for the first coil C1.

In some embodiments, the first coil unit 120 may correspond to a primary coil of the transformer 100, and the second coil unit 130 may correspond to a secondary coil of the transformer 100. However, the present disclosure is not necessarily limited thereto.

Further, the diameter of the second coil C2 may be 0.7 to 0.9 times the height of the second bobbin B2 in the third axis direction, but the present disclosure is not necessarily limited thereto.

The first coil unit 120 will be described in more detail with reference to fig. 3a and 3b, and the second coil unit 130 will be described in more detail with reference to fig. 4a to 4 c.

In a state where the first coil unit 120 and the second coil unit 130 are coupled to each other, the terminal bobbin 140 is coupled thereto to be oriented in the first axial direction, and the terminal coil is provided with a terminal via which the first coil C1 is electrically connected to an external circuit (not shown). The detailed construction of the terminal bobbin 140 will be described in more detail later with reference to fig. 5a and 5 b.

The core fixing unit 150 is provided to ensure stable coupling between the upper core 111 and the lower core 112. The core fixing unit may be implemented by winding a sheet of polymer resin tape around the outer surface of the core unit 110 at least once in the second and third axial directions, but the present disclosure is not necessarily limited thereto.

Fig. 3a is a perspective view of the first bobbin according to the embodiment, and fig. 3b is a plan view of the first bobbin according to the embodiment.

Referring to fig. 3a and 3B, the first bobbin B1 according to the embodiment may include a first top plate TP1, a first bottom plate BP1, and a first sidewall SW1 disposed between the first top plate TP1 and the first bottom plate BP 1. The first sidewall SW1 may define a first cavity CH1 and may define a receiving space to receive the first coil C1 together with a lower surface of the first top plate TP1 and an upper surface of the first bottom plate BP 1.

The first top plate TP1 may have a first extraction groove DH1 and a second extraction groove DH2, the first extraction groove DH1 and the second extraction groove DH2 being formed in edges of portions of the first top plate coupled with the terminal bobbin 140 in the first axial direction. One of the two end portions of the wire constituting the first coil C1 may be drawn upward through the first drawing groove DH1, and the remaining end portion of the first coil C1 may be drawn upward through the second drawing groove DH 2. Both end portions of the first coil C1 respectively drawn through the first drawing groove DH1 and the second drawing groove DH2 may extend to a region above the terminal bobbin 140. Further, the first extraction groove DH1 and the second extraction groove DH2 may overlap with a second recess RC2 in the terminal bobbin 140 in the third axis direction, which will be described later.

Fig. 4a is a plan view of the second bobbin according to the embodiment, fig. 4b is a perspective view of the second bobbin according to the embodiment, and fig. 4c is a rear perspective view of the second bobbin according to the embodiment.

Referring to fig. 4a to 4c, the second bobbin B2 according to the embodiment may include a second top plate TP2, a second bottom plate BP2, and a second sidewall SW2 disposed between the second top plate TP2 and the second bottom plate BP 2. The second sidewall SW2 may define a second cavity CH2 and may define a receiving space to receive the second coil C2 together with a lower surface of the second top plate TP2 and an upper surface of the second bottom plate BP 2.

The first protruding portion PT1 and the second protruding portion PT2 protruding upward in the third axis direction may be provided on a portion of the second top plate TP2 coupled with the terminal bobbin 140 in the first axis direction, and the first partition wall portion PA1 bent and extending upward in the third axis direction may be provided on an edge of a portion of the second top plate TP2 opposite to the terminal bobbin 140 in the first axis direction.

The third protruding portion PT3, the fourth protruding portion PT4, the second partition wall portion PA2, the first supporting portion SP1, and the first concave portion RC1 protruding downward in the third axis direction may be provided on one of the portions of the second bottom plate BP oriented in the first axis direction. Further, the plurality of second terminals TM2 and the second support portion SP2 may be provided on an opposite one of the plurality of portions of the second base plate BP oriented in the first axial direction. The plurality of second terminals TM2 may be disposed parallel to each other while being spaced apart from each other in the second axis direction.

The first recess RC1 may have a planar shape (planar shape) recessed toward the opposite side thereof at one side end of the second bottom plate BP. The width of the first concave portion RC1 in the second axial direction may gradually decrease from one side end toward the opposite side. For example, the first concave portion RC1 may have a semicircular or semi-elliptical planar shape, but the present disclosure is not necessarily limited thereto. A portion of the second coil C2 may be exposed through the first concave portion RC1, which will be described in more detail later with reference to fig. 7d to 7 f.

The second partition wall portion PA2 may extend in the second axial direction, and the first support portion SP1 may protrude from the second partition wall portion PA2 toward the opposite side (i.e., the center of the second cavity CH 2) in the first axial direction. The second support portion SP2 may protrude toward one side in the first axial direction, and may support the first coil unit 120 together with the first support portion SP1 when the first coil unit 120 is inserted into the second cavity CH2 from top to bottom in the third axial direction.

Meanwhile, when viewed in a plan view, a second wire guide WG2 may be provided between the first partition wall portion PA1 and the plurality of terminals TM 2. The second wire guide WG2 may include a center portion wg2_c and side portions wg2_s1 and wg2_s2. The center portion wg2_c may protrude from the second side-wall portion SW2 toward the second terminal TM2, and its width in the second axis direction may gradually decrease toward the second terminal TM 2. The side portions wg2_s1 and wg2_s2 may have a plate shape, and may be provided to connect the lower end of the first partition wall portion PA1 to the center portion wg2_c. For example, each of the side portions wg2_s1 and wg2_s2 may have an arc-shaped plane connecting the lower end of the first partition wall portion PA1 to the center portion wg2_c, and the second wire guide wg2 may have a T-shaped plane.

The second wire guide WG2 may be used to guide a wire disposed at an innermost position among a plurality of wires constituting the second coil C2. Further, a plurality of wires (not shown) constituting the second coil C2 are exposed upward at portions of the second top plate TP2 and the second bottom plate BP2 that do not overlap each other in the third axis direction (i.e., between the first partition wall portion PA1 and the second terminal TM2 when viewed in a plan view). Accordingly, the side portions wg2_s1 and wg2_s2 of the second wire guide wg2 may help to ensure insulation distances between the second coil C2 and the first coil C2 and between the second coil and the core unit 110 together with the first partition wall portion PA 1.

The protruding portions PT1, PT2, PT3, and PT4 may be fitted into holes H1, H2, H3, and H4 (which will be described later) in the terminal bobbin 140, respectively, so that the second bobbin B2 and the terminal bobbin 140 are coupled and fixed to each other.

Fig. 5a is a plan view of the terminal bobbin according to the embodiment, and fig. 5b is a perspective view of the terminal bobbin according to the embodiment.

Referring to fig. 5a and 5b together, the terminal bobbin 140 may include a third top plate TP3, a third bottom plate BP3, and a third side wall SW3 disposed between the third top plate TP3 and the third bottom plate BP 3.

The first hole H1, the second hole H2, and the first wire guide WG1 may be provided on the third top plate TP3, and the third hole H3 and the fourth hole H4 may be provided in the third bottom plate BP 3.

An opening OP is formed in a side of the terminal bobbin 140 where the third side wall SW3 is not provided such that the second coil unit 130 is inserted therein in the first axial direction, and a plurality of first terminals TM1 are provided on a side of the terminal bobbin 140 opposite to the opening in the first axial direction. The second concave portions RC2 may be formed in the third top plate TP3 and the third bottom plate BP3, respectively, so as to be disposed above and below the opening OP in the third axis direction, and concave toward opposite sides in the first axis direction. In this case, the second recess formed in the third top plate TP3 and the second recess formed in the third bottom plate BP3 may have different planar shapes, but the present disclosure is not necessarily limited thereto. The planar shape of the second concave portion RC2 may be preferably set such that the terminal bobbin 140 coupled with the first coil unit 120 and the second coil unit 130 does not shield the first coil unit 120 (i.e., does not overlap the first coil unit 120 in the third axis direction) or shields a minimum required portion of the first coil unit 120. The reason for this is to prevent heat generated from the first coil C1 of the first coil unit 120 from being trapped by the terminal bobbin 140.

Each of the plurality of first wire guides WG2 may extend from the second recess RC2 toward a corresponding one of the first terminals TM1. The number of first terminals TM1 and the number of first wire guides WG1 may be the same as each other, but the present disclosure is not necessarily limited thereto. One end of the first coil C1 may be drawn through any one of the drawing grooves DH1 and DH2 in the first bobbin B1, and may be exposed upward through the second recess RC2 formed in the third top plate TP 3. The exposed end of the first coil C1 may extend toward the first terminal TM1 along the first wire guide WG1, and may be electrically connected to the first terminal TM1.

Each of the plurality of first terminals TM1 may be implemented as a terminal pin TP that extends in the first axis direction and is bent in the third axis direction. The portion of the terminal pin TP extending in the first axial direction may be electrically connected and fixed to one end portion of the first coil C1 by soldering, and the portion of the terminal pin TP extending in the third axial direction may pass through the terminal bobbin 140 downward in the third axial direction to be exposed downward from the terminal bobbin 140. The portion exposed downward from the terminal bobbin 140 may be electrically connected and fixed to the circuit board. The configuration of the first terminal TM1 using the terminal pin TP can also be applied to the second terminal TM2.

In addition to the above-described core fixing unit 150, the transformer 100 according to the embodiment may include a plurality of adhesive portions to ensure higher reliability. This will be described with reference to fig. 6.

Referring to fig. 6, first to third adhesive portions AD1, AD2 and AD3 may be provided between the first top plate TP1 of the first bobbin B1 of the first coil unit 120 and the surface of the core unit 110 having the opening, whereby the core unit 110 and the first coil unit 120 may be more firmly coupled to each other.

Further, a fourth adhesive portion AD4 may be provided between the second concave portion RC2 in the terminal bobbin 140 and the first top plate TP 1.

Further, the fifth and sixth adhesive portions AD5 and AD6 may be provided to extend along a contact line between the first and second coil units 120 and 130 in the first axial direction. Of course, the fifth and sixth adhesive portions AD5 and AD6 may contact the lower surface of the body portion of the upper core 111 or the upper surface of the body portion of the lower core 112 and the contact line between the first and second coil units 120 and 130.

Each of the adhesive portions may be an adhesive resin, but the present disclosure is not necessarily limited thereto. Further, although not shown, adhesive portions may be formed on coupling portions between the first to fourth protruding portions PT1, PT2, PT3 and PT4 and the first to fourth holes H1, H2, H3 and H4.

Hereinafter, the arrangement of the second coil C2 according to the embodiment will be described in more detail with reference to fig. 7a to 7 g.

For convenience of explanation, although the second coil C2 is shown in fig. 7a as being disposed on the second bobbin B2, it should be noted that, in practice, the second coil C2 is disposed between the second top plate TP2 and the second bottom plate BP2 of the second bobbin B2.

Referring to fig. 7a, the second bobbin B2 may include: a central portion CP; a first portion 1P; on one side of the central portion CP or the second through hole CH2 in the first axial direction; and a second portion 2P located at the other side of the center portion CP or the second through hole CH2 opposite to the first portion 1P in the first axis direction.

The second through hole CH2 may be provided in the central portion CP, and a plurality of terminal pins T1, T2, T3, T4, T5, T6, T7, and T8 constituting the second terminal TM2 may be provided on the first portion 1P in parallel to each other in the second axis direction.

The second coil C2 may include a plurality of wires L1, L2, L3, and L4.

Each of the plurality of conductive lines L1, L2, L3, and L4 may have both ends, each of which is electrically connected to a corresponding one of the plurality of terminal pins T1, T2, T3, T4, T5, T6, T7, and T8, and may form one turn around the second through hole CH 2.

For example, both ends of the first wire L1 are connected to the second terminal pin T2 and the fifth terminal pin T5, and both ends of the third wire L3 are connected to the first terminal pin T1 and the sixth terminal pin T6, respectively. Further, both ends of the second wire L2 are connected to the fourth terminal pin T4 and the seventh terminal pin T7, respectively, and both ends of the fourth wire L4 are connected to the third terminal pin T3 and the eighth terminal pin T8, respectively.

Meanwhile, the first and third wires L1 and L3 may intersect the second and fourth wires L2 and L4 at the second portion 2P so as to at least partially overlap the second and fourth wires L2 and L4 in the third axis direction. Further, the plurality of wires L1, L2, L3, and L4 may be disposed parallel to each other in the second axial direction on the central portion CP, and may extend in the first axial direction. Although it is shown in fig. 7a that the plurality of wires L1, L2, L3, and L4 are not overlapped with each other in the third axis direction on the central portion CP, the plurality of wires L1, L2, L3, and L4 may be partially overlapped with each other in the third axis direction in a region adjacent to the second portion 2P. That is, one side of each of the plurality of wires L1, L2, L3, and L4 may extend to be disposed on the second portion 2P, and the other side thereof may extend so that both ends thereof are disposed on the first portion 1P.

Due to the above-described configuration of the second coil unit 130, the wires constituting the second coil C2 partially overlap each other on the second portion 2P. However, since each individual wire forms only one turn, it is understood that the second coil C2 is wound in one layer.

From a circuit point of view, a connection structure of terminal pins and intersections on the above-mentioned second portion 2P is established in order to achieve an inductive matching between the portions forming the same turns.

This will be described with reference to fig. 7b and 7 c.

Referring to fig. 7b and 7c, the first and third wires L1 and L3 are connected in parallel with each other to form a first turn portion NS2 of a first signal for the secondary coil unit of the transformer, and the second and fourth wires L2 and L4 form a second turn portion NS3 of a second signal for the second coil unit. In this case, the first terminal pin T1 and the second terminal pin T2 correspond to input terminals of the first signal, and the fifth terminal pin T5 and the sixth terminal pin T6 correspond to a ground portion of the first signal. Further, the seventh terminal pin T7 and the eighth terminal pin T8 correspond to input terminals of the second signal, and the fourth terminal pin T4 and the fifth terminal pin T5 correspond to ground portions of the second signal. Here, the ground portions of the signals may be electrically connected to each other to form a so-called Center Tap (CT) structure.

Referring back to fig. 7a, due to the above-described connection between the wires and the terminal pins, the first wire L1 and the third wire L3 (arranged in parallel to constitute the first turn portion NS 2) are mirror images (symmetrical) of the second wire L2 and the fourth wire L4 (arranged in parallel to constitute the second turn portion NS 3) with respect to the second through hole CH2 in the first axial direction, as seen in a plan view. Accordingly, the first and second turn portions NS2 and NS3 have substantially the same wire configuration, and thus, inductance variation due to a difference in length between wires can be reduced as much as possible, resulting in reduction of heat generated due to current concentration.

Meanwhile, since the wires intersect each other on the second portion 2P of the second bobbin B2, the wires may overlap each other in the third axis direction. Therefore, it is necessary to ensure that the height of the second side wall SW2 of the second bobbin B2 is at least twice the wire thickness to prevent the second bobbin B2 from being deformed at the second portion 2P. However, ensuring the height of the second side wall SW2 may cause the second bobbin B2 to become thick as a whole, which may increase the overall thickness of the transformer. This will be described with reference to fig. 7 d.

Fig. 7d is a view for explaining an overlapping pattern of wires on the second portion of the second coil unit according to an embodiment. In fig. 7d, the wires L1, L2, L3 and L4 are shown by solid lines for better understanding, whether overlapping or not.

Referring to fig. 7d, a plurality of overlapping areas are generated on the second portion 2P of the second coil unit according to the overlapping pattern of the paired plurality of wires. For example, the first region A1, the second region A2, the third region A3, and the fourth region A4 are generated on the second portion 2P, and the third wiring L3 and the fourth wiring in the first region A1 overlap each other when seen in a plan view; the first wire L1 and the fourth wire L4 in the second area A2 overlap each other when seen in a plan view; the second wire L2 and the third wire L3 in the third area A3 overlap each other when seen in a plan view; the first wire and the second wire in the fourth area A4 overlap each other when seen in a plan view.

These areas A1, A2, A3, and A4 require a larger receiving space in the third axis direction than the remaining areas.

Accordingly, the first concave portion RC1 may be formed in the second bobbin B2 to prevent an increase in thickness of the second bobbin B2.

Fig. 7e is a rear view of the second coil unit according to the embodiment, and fig. 7f is a side view of the second coil unit shown in fig. 7e when the upper part of fig. 7e is viewed in the direction of the arrow.

Referring to fig. 7e and 7f together, a first recess RC1 having a semicircular planar shape is formed in the second bottom plate BP2 of the second coil unit 130. Although the height h2 of the receiving space (i.e., the height of the second side wall SW 2) is less than twice the wire diameter D as shown in fig. 7f, due to the presence of the first concave portion RC1, it is possible to secure an intersecting space between wires without deforming the bobbin. Therefore, the thickness of the second bobbin B2 can be prevented from increasing.

Meanwhile, it is preferable that the maximum length h1 of the first concave portion RC1 in the first axial direction is greater than twice (2*D) of the diameter of each wire, as shown in fig. 7 d. Further, it is preferable that the first concave portion RC1 is formed at a position including at least a part of each of the four areas A1, A2, A3, and A4, the four areas A1, A2, A3, and A4 being generated by overlapping between the wires shown in fig. 7 d. Further, it is preferable that the planar area of the first concave portion RC1 is 50% to 90% of the sum of the areas of the four areas A1, A2, A3, and A4 generated by overlapping between the wires, but the present disclosure is not necessarily limited thereto.

Further, the first concave portion RC1 is shown in fig. 11a as having a semicircular planar shape, but this is merely illustrative. The planar shape of the first concave portion is not limited to any particular shape (e.g., circular, rail-like, or polygonal) as long as the shape can enclose at least a portion of each of the four areas A1, A2, A3, and A4 generated by overlapping between the wires.

The configuration of the second bobbin B2 according to another embodiment shown in fig. 7g is the same as that of the second bobbin B2 described above with reference to fig. 4a except for the short circuit portions SP1, SPC and SP2, and thus a repetitive description will be omitted.

Referring to fig. 7g, the first terminal pin T1 and the second terminal pin T2 corresponding to the input terminal of the first signal may be short-circuited through the first short-circuit portion SP 1. Further, the seventh terminal pin T7 and the eighth terminal pin T8 corresponding to the input terminal of the second signal may be short-circuited through the second short-circuit portion SP 2. Further, the third to sixth terminal pins T3, T4, T5 and T6 corresponding to the ground portion of the center tap configuration may be short-circuited through the center short-circuit portion SPC.

Here, each of the short circuit portions SP1, SP2 and SPC may be implemented by welding. However, this is merely illustrative and the present disclosure is not necessarily limited thereto. Any of a variety of schemes capable of shorting the terminal pins may be used. For example, each of the short circuit portions SP1, SP2 and SPC may be implemented by a conductive clip, a conductive pin or a combination of the above, and soldering.

Although the central shorting portion SPC is shown as one body and shorts all of the third to sixth terminal pins T3, T4, T5 and T6 in fig. 7g, according to another aspect, the central shorting portion SPC may include a first central shorting portion (not shown) for shorting the third terminal pin T3 and the fourth terminal pin T4 and a second central shorting portion (not shown) for shorting the fifth terminal pin T5 and the sixth terminal pin T6. In this case, the first center short portion (not shown) and the second center short portion (not shown) may not be electrically connected to each other in the transformer.

Meanwhile, as described above, the transformer 100 according to the embodiment may constitute a circuit board (not shown) that constitutes a Power Supply Unit (PSU) together with other magnetic elements (e.g., inductors).

Fig. 8a is a perspective view of a transformer according to yet another embodiment, and fig. 8b is a plan view of a transformer according to yet another embodiment. Further, fig. 9 is an exploded perspective view of a transformer according to still another embodiment, and fig. 10 is a perspective view of a first bobbin according to still another embodiment. Further, fig. 11 is an exploded perspective view of a bobbin unit according to still another embodiment.

Referring to fig. 8a to 11 together, a transformer 101 according to still another embodiment may include a core unit 110, bobbin units B1 and B2, and terminals TM1 and TM2. Hereinafter, each component will be described in detail.

The core units 111 and 112 may have a function of a magnetic circuit, and thus may serve as a path of magnetic flux. The core units 111 and 112 may include an upper core 111 disposed at an upper position and a lower core 112 disposed at a lower position. The two cores 111 and 112 may be formed to be symmetrical or asymmetrical to each other in the vertical direction. However, for convenience of explanation, it is assumed that the following description is made in a case where two cores are formed to be vertically symmetrical to each other.

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) 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 leg portions OL1-1 and OL1-2 extending in one axial direction (herein, Y-axis direction) and being spaced apart from each other in the other axial direction (herein, X-axis direction) when viewed in plan view, and one center leg portion CL1 disposed between the two outer leg portions OL1-1 and OL 1-2.

When the upper core 111 and the lower core 112 are coupled to each other in the vertical direction, each of the outer struts OL1-1 and OL1-2 and the center strut CL1 of the upper core 111 faces a corresponding one of the outer struts OL2-1 and OL2-2 and the center strut CL2 of the lower core 112. The pair of outer struts OL1-1 and OL2-1 facing each other may be referred to as a first outer strut portion, the other pair of outer struts OL1-2 and OL2-2 facing each other may be referred to as a second outer strut portion, and the pair of central struts CL1 and CL2 facing each other may be referred to as a central strut portion.

A gap having a predetermined distance (e.g., 10 μm to 200 μm, but not necessarily limited thereto) may be formed between at least one of the pair of outer struts and the pair of center struts facing each other. The size of the gap between the pair of central struts and between each of the two pairs of outer struts may be adjusted so as to control the inductance of the core unit 110, and the amount of heat generated may be controlled by varying the number of gaps.

Further, the core unit 110 may include a magnetic material (e.g., iron or ferrite), but the present disclosure is not necessarily limited thereto.

Because the core unit 110 surrounds a portion of the outer circumference of the bobbin units 120 and 130, it can be seen that a portion of the first coil unit (not shown) and a portion of the second coil unit (not shown), which are received in the bobbin units 120 and 130, are disposed inside the core unit 110.

The bobbin units 120 and 130 may include a first bobbin B1 and a second bobbin B2.

The first and second bobbins B1 and B2 may have first and second through holes TH1 and TH2 formed therein, respectively, and the center legs CL1 and CL2 of the core unit 110 may be aligned to pass through the first and second through holes TH1 and TH2.

At least a portion of the first bobbin B1 may be received in the second bobbin B2, and may include a first top portion 121, a first middle portion 123, and a first bottom portion 122.

Each of the first top part 121 and the first bottom part 122 may have a quadrangular plan shape with rounded corners, but the present disclosure is not necessarily limited thereto. Further, the first bottom portion 122 may have a planar shape that extends further outward than the first top portion 121 in a direction in which the pillar portions are spaced apart from each other (i.e., X-axis direction).

The first middle portion 123 may be disposed between the first top portion 121 and the first bottom portion 122 in a vertical direction, and may electrically insulate the center pillar portion from a wire (not shown) constituting the first coil unit. An inner side surface of the first intermediate portion 123 may define a first through hole TH1. Further, a space defined by a lower surface of the first top portion 121, an outer side surface of the first middle portion 122, and a portion of an upper surface of the first bottom portion may be used as a receiving space for receiving a wire constituting the first coil unit.

The second bobbin B2 may include a second top portion 131, a second middle portion 133, a second bottom portion 132, and plate supporting portions CBS1 and CBS2.

The second middle portion 133 may be disposed between the second top portion 131 and the second bottom portion 132 in a vertical direction, and may electrically isolate wires (not shown) constituting the second coil unit from wires (not shown) constituting the first coil unit. Further, a space defined by a portion of the lower surface of the second top portion 131, an outer side surface of the second middle portion 132, and a portion of the upper surface of the second bottom portion may be used as a receiving space for receiving a wire constituting the second coil unit.

Further, the board support portions CBS1 and CBS2 spaced apart from each other in the long axis direction of the second bottom portion 132 may be used to support the transformer 101 when the transformer 101 is mounted on a circuit board (not shown) of a device (e.g., PSU). The plurality of protruding portions 136 may be formed among the plurality of board supporting portions in the vicinity of the second board supporting portion CBS2 adjacent to the second terminal TM2 so as to protrude downward, and are disposed parallel to each other while being spaced apart from each other in the y-axis direction. The protruding portion 136 may support the transformer 101 on the board together with the second board supporting portion CBS2, and may also serve as a wire to guide an end of the wire constituting the second coil unit to extend to the second terminal TM2, the end of the wire being led out between the second top portion 131 and the second bottom portion 132.

A second through hole TH may be provided in a central portion of the second top portion 131, and terminals TM1 and TM2 may be provided on respective ends of the second top portion 131 in the long axis direction thereof. The terminals TM1 and TM2 may be used to fix the transformer 101 to a board (not shown) of the Power Supply Unit (PSU), and may serve as an electrical connection path between the first and second coil units (not shown) of the transformer 101 and the board (not shown) of the Power Supply Unit (PSU).

In more detail, the first terminal TM1 may include a plurality of pins spaced apart from each other, and any one of both ends of the wire constituting the first coil unit may be electrically connected to at least one of the plurality of pins. For example, some of the plurality of pins constituting the first terminal TM1 may be opposite to other pins along the x-axis, and may be disposed parallel to each other along the y-axis, while other pins may be disposed parallel to each other along the y-axis.

The second terminal TM2 may include a plurality of pins disposed parallel to each other while being spaced apart from each other along the x-axis, and any one of both ends of the wire constituting the second coil unit may be electrically connected to at least one of the plurality of pins.

The first guide 134 and the second guide 135 are disposed on the upper surface of the second top portion 131 so as to face each other in the long axis direction (i.e., Y axis direction) of the second bobbin B2 (the second through hole TH2 is interposed between the first guide 134 and the second guide 135), and extend in the short axis direction (i.e., X axis direction). Here, the first guide 134 may be disposed adjacent to the second terminal TM2, and the second guide may be disposed adjacent to the first terminal TM 1. The upper core 111 may be located between the first guide 134 and the second guide 135, and may serve to fix the position of the upper core 111 and increase the insulation distance between the upper core 111 and the terminals TM1 and TM 2.

Further, a reinforcing pattern portion 136 may be provided between the first guide 134 and the second terminal TM2 on the upper surface of the second top portion 131. For example, the reinforcement pattern portion 136 may be formed such that patterns having F-shaped planes are disposed opposite to each other in the X-axis direction, but the present disclosure is not necessarily limited thereto. The rigidity of the second top portion 131 may be increased by the reinforcing pattern portion 136, so that it may be prevented from being deformed. Due to the height difference between the reinforcing pattern portion 136 and the second top portion 131, the plurality of concave portions H1 and H2 may be formed to extend in the X-axis direction, and may serve to increase the insulation distance between the upper core 111 and the second terminal TM 2.

When the transformer 101 is constructed, at least a portion of the first bobbin B1 may be received in a recess RC defined by a lower surface of the second top portion 131 and an inner side surface of the second intermediate portion 133 of the second bobbin B2.

Further, in a state where the first bobbin B1 and the second bobbin B2 are coupled to each other, the upper surface of the first top portion 121 faces the lower surface of the second top portion 131, and a portion (i.e., an outwardly extending portion) of the upper surface of the first bottom portion 122, which does not overlap with the first top portion 121 in the vertical direction, faces the lower surface of the second bottom portion 132.

Further, in the coupled state, the coil lead-out portion 124 of the first top portion 121 may pass through the third through hole TH3 in the second top portion 131, and may be exposed upward. By means of the coil lead-out portion 124, both ends of the wire constituting the first coil unit can be easily led out and fixed to the upper surface of the second top portion 131, and can be directly connected to the first terminal TM1.

Further, on the upper surface of the first top portion 131 of the first bobbin B1, a protruding pin 125 is provided between the first through hole TH1 and the coil lead-out portion 124 so as to protrude upward and extend in the X-axis direction. When the first bobbin B1 and the second bobbin B2 are coupled to each other, the protruding pin 125 may be inserted into a blind hole BH formed in the lower surface of the second top portion 131 at a position corresponding to the second guide 135. Therefore, the first bobbin B1 and the second bobbin B2 can be more firmly and stably coupled to each other, and a cross section thereof in a coupled state is shown in fig. 6A.

Meanwhile, a configuration for bonding the bobbin units B1 and B2 and the core unit 110 to each other may be considered in order to achieve firm coupling therebetween. For example, as shown in fig. 1B, the first adhesive groups AD1, AD2, AD3, and AD4 may be disposed in a side-joining manner between the outer leg of the core unit 110 and the portions of the bobbins B1 and B2 extending from the receiving spaces in the core unit 110 in the Y-axis direction so as to be exposed. For example, the first adhesive groups AD1, AD2, AD3, and AD4 may be in contact with or out of contact with the bobbins B1 and B2. Preferably, the first adhesive groups AD1, AD2, AD3, and AD4 are in contact with both the upper core 111 and the lower core 112, so that the upper core 111 and the lower core 112 are fixed to each other.

Further, second adhesive groups AD5 and AD6 may be provided between a portion of the lower surface of the upper core 111 (corresponding to a region between the center pillar and the outer pillar) and the upper surface of the second bobbin B2. By means of the above-described adhesive portions AD1, AD2, AD3, AD4, AD5, and AD6, vibrations due to gaps between the bobbins B1 and B2 and the core unit 110 can be prevented. Here, the first adhesive groups AD1, AD2, AD3, and AD4 and the second adhesive groups AD5 and AD6 may be implemented as adhesives having the same composition, or may be implemented as adhesives having different compositions. Preferably, the second adhesive groups AD5 and AD6 are implemented as adhesive resins, but the present disclosure is not necessarily limited thereto.

A receiving state in which each of the first coil unit and the second coil unit is received due to the above-described coupling structure of the bobbin units B1 and B2 will be described with reference to fig. 5.

Fig. 12 is a cross-sectional view of the transformer according to this embodiment taken along line B-B' in fig. 8B.

Referring to fig. 12, bobbins B1 and B2 are disposed between the core unit 110 and the coil units 120 and 130. In more detail, the coil units 120 and 130 and the bobbins B1 and B2 are partially disposed in the first space B1 and the second space SB2 in the core unit 110. The first space SB1 and the second space SB2 may be spaced apart from each other in a direction in which the pillar portions are spaced apart from each other (i.e., the X-axis direction), with the center pillar portions CL1 and CL2 interposed therebetween, and may be formed such that a rectangular plane extends in the Y-axis direction. Further, the first space SB1 may be located between the central leg portions CL1 and CL2 and the outer leg portions OL1-1 and OL2-1 located at one side of the core unit 110, and the second space SB2 may be located between the central leg portions CL1 and CL2 and the outer leg portions OL1-2 and OL2-2 located at the opposite side of the core unit 110.

The first bobbin B1 may have a first receiving portion RP1 receiving the first coil unit 140 and a first extending portion EP1 extending from the first receiving portion RP1 toward the second bobbin 130. That is, the first receiving portion RP1 may correspond to a portion of the first top portion 121, the first middle portion 123, and the first bottom portion 122 other than the first extending portion EP1.

The second bobbin 130 may have a second receiving portion RP2 receiving the second coil unit 130 and a second extending portion EP2 extending from the second receiving portion RP2 toward the first bobbin B1. That is, the second receiving portion RP2 may include a portion of the second top portion 131, the second middle portion 133, and the second bottom portion 132 in addition to the second extending portion EP2.

Further, the second receiving portion RP2 is provided on the first extending portion EP1, and the first receiving portion RP1 is provided below the second extending portion EP2. Therefore, the shortest distance h1 from the lower surface of the lower core 112 to the first coil unit 120 is different from the shortest distance h2 from the lower surface of the lower core 112 to the second coil unit 130. That is, the shortest distance h1 from the lower surface of the lower core 112 to the first coil unit 120 is shorter than the shortest distance h2 from the lower surface of the lower core 112 to the second coil unit 130. For example, the shortest distance h1 from the lower surface of the lower core 112 to the first coil unit 120 may be 0.3 to 0.7 times the shortest distance h2 from the lower surface of the lower core 112 to the second coil unit 130.

Further, due to the above-described coupling structure of the bobbin units B1 and B2, a portion of the first coil unit 120 and a portion of the second coil unit 130 overlap each other in a direction from the outer leg portion located at one side toward the outer leg portion located at the opposite side, and the remaining portions thereof do not overlap each other. The first coil unit 120 and the second coil unit 130 may not overlap each other in the vertical direction.

At least a portion of the second coil unit 130 is disposed beside the first coil unit 120, and a portion of the second receiving portion RP2 (i.e., the second intermediate portion 133) is disposed between the first coil unit 120 and the second coil unit 130 in the horizontal direction.

Each of the first coil unit 120 and the second coil unit 130 may be a multi-turn winding in which a rigid metal conductor (e.g., copper wire) is wound a plurality of times, but the present disclosure is not necessarily limited thereto. Further, the thickness of the wire constituting the second coil unit 130 may be 50% to 150% of the thickness of the wire constituting the first coil unit 120, but the present disclosure is not necessarily limited thereto.

Meanwhile, insulating units 161 and 162 may be provided between the coil frames B1 and B2 and the corresponding outer leg portions. The insulating units 161 and 162 may extend from an area on the upper surface of the second receiving portion RP2 to the outside of the second receiving portion RP2, and then may be bent and extended to surround the second receiving portion RP2 and the outside of the first extending portion EP1, and then may be bent and extended to an area on the lower surface of the first extending portion EP 1. Thus, both the second coil unit 130 and the first coil unit 120 may be electrically insulated from the outer leg portion of the core unit 110. The insulating units 161 and 162 may include a material (e.g., ketone or polyimide) having excellent insulating properties, but the present disclosure is not necessarily limited thereto.

Due to the above structure, the insulation distance between the first coil unit 120 and the core unit 110 can be greatly increased. For example, if the second extension portion EP2 is not present, the first insulation distance PATH1 from the upper side of the first coil unit 120 directly extends to the lower surface of the upper bobbin. However, due to the presence of the second extension portion EP2, the first insulation distance PATH1 extends in the x-axis direction by a length equal to or longer than the length of the second extension portion. Further, the second insulation distance PATH2 from the lower side of the first coil unit 120 extends by a length equal to the sum of the length of the first extension portion EP1 in the x-axis direction and the length of each of the insulation units 161 and 162 in the same direction.

Further, in addition to the leakage inductance obtained by the shortest distance β between the first coil unit 120 and the second coil unit 130, since the first receiving portion RP1 and the second receiving portion RP2 are misaligned in the horizontal direction, an additional leakage inductance can be ensured.

Hereinafter, a section of a portion not surrounded by the core unit 110 will be described with reference to fig. 13a and 13 b.

Fig. 13a is a cross-sectional view of a transformer according to another embodiment taken along line A-A' of fig. 8b, and fig. 13b is an enlarged view of portion C of fig. 13 a.

Referring to fig. 13a and 13B together, the first extended portion EP1 may not be provided in the first bobbin B1 in the region where the bobbin units B1 and B2 are not surrounded by the core unit 110. Further, the shortest distance α between the first coil unit 120 and the second coil unit 130 in the region where the bobbin units B1 and B2 are not surrounded by the core unit 110 (i.e., in the region outside the first space SB1 and the second space SB 2) may be the same as or different from the shortest distance β between the first coil unit 120 and the second coil unit 130 in the region where the bobbin units B1 and B2 are surrounded by the core unit 110.

Preferably, the shortest distance ratio (β/α) may be 1 to 1.3. When the shortest distance ratio (β/α) is less than 1, the overall size of the transformer 101 increases, and the variation in leakage inductance is not large. On the other hand, when the shortest distance ratio (β/α) exceeds 1.3, the energy conversion efficiency of the transformer 101 decreases. However, the shortest distance ratio (β/α) having the above range is a value determined when the cutting line A-A 'and the cutting line B-B' in fig. 8B intersect each other at the center of the center pillar portion when viewed in a plan view, and may vary according to the radius of curvature of each of the first intermediate portion 123 and the second intermediate portion 133 in the winding direction.

Hereinafter, a configuration of the transformer 101 and a circuit in which the transformer 101 may be mounted according to an embodiment will be described with reference to fig. 14.

Referring to fig. 14, a circuit configuration of a power supply unit (i.e., PSU) of an electronic product (e.g., a flat panel television) including a square wave generator 210, a resonator 220, and a rectifier 230 is shown. Flat televisions typically support not only a normal mode but also various other modes of operation (e.g., low power modes), and it is desirable to efficiently implement each mode of operation. Thus, the resonator 220 is implemented in the form of an LLC resonant converter. The LLC resonant converter comprises a first inductor (Lr) 221, a second inductor (Lm) 222 and a capacitor (Cr) 223. The inductance (Lm) of the second inductor 222 may be considered to be the inductance of the operating circuit. The resonance frequency varies according to the operating frequency of the PSU, and the inductance (Lr) of the first inductor 221 and the capacitance (Cr) of the capacitor 223 are factors that determine the operating frequency. If the inductance (Lr) of the first inductor 221 and the capacitance (Cr) of the capacitor 223 are not set to appropriate values, the overall efficiency of the circuit may be reduced or the circuit may malfunction.

The inductance (L) value of the leakage inductance integrated transformer (e.g., the transformer 101 according to the present embodiment) corresponds to "Lm" in the resonator 220, and the leakage inductance (Lk) value thereof corresponds to "Lr" in the resonator 220.

The PSU of a conventional flat panel television requires a ratio (Lk/Lm) of 10% to 20%, but the "Lk" value of a conventional transformer is too low to meet the ratio requirement.

In more detail, the leakage inductance of the transformer can be obtained using the following equation 1.

[ equation 1]

L _k ＝(1-k)*L _m

In equation 1, "Lk" represents leakage inductance, "k" represents coupling coefficient (coupling coefficient), and "Lm" represents inductance of the transformer. Here, the coupling coefficient k may be obtained through experiments, and may be obtained using the following equation 2, for example.

[ equation 2]

k＝0.7307-[0.0556*In(X)]

In equation 2, "X" represents a gap ratio (specifically, a ratio of a spacing distance between the first coil unit and the second coil unit to a shortest distance between an outermost periphery of the first coil unit and an outer leg portion adjacent to the outermost periphery of the first coil unit) defining a space in which the second coil unit can be wound (hereinafter referred to as a "winding space" for convenience).

In more detail, when both the first bobbin B1 and the second bobbin B2 exist, the shortest distance (i.e., β in fig. 5) between the first coil unit 120 and the second coil unit 130 corresponds to the distance between the outermost circumference of the first coil unit 120 and the innermost circumference of the second coil unit 130. Further, if only the first bobbin B1 is present, the maximum allowable value of the distance between the second coil unit 130 and the first coil unit 120 in the winding space in which the second coil unit 130 can be present corresponds to the shortest distance from the outermost periphery of the first coil unit 120 to the adjacent outer leg portion thereof (i.e., d1 in fig. 12).

The leakage inductance of the transformer varies according to the coupling coefficient, and the coupling coefficient is particularly affected by the shortest distance between the first coil unit 120 and the second coil unit 130 in the core unit 110.

However, the shortest distance β between the first coil unit 120 and the second coil unit 130 depends on the position of the innermost circumference of the second coil unit 130 in the winding space. When only the increase in the shortest distance β is concerned, the number of turns of the second coil unit 130 is limited to a limited winding space. Further, in order to increase the size of the winding space, it is necessary to increase the size of the core unit 110, and thus the degree of increase in the size of the winding space is limited.

Accordingly, in this embodiment, leakage inductance can be ensured by controlling the gap ratio (i.e., the ratio of the shortest distance β between the first coil unit 120 and the second coil unit 130 to the shortest distance d2 from the outermost periphery of the first coil unit 120 to the outer leg portion adjacent thereto).

For example, the shortest distance β between the first coil unit 120 and the second coil unit 130 is preferably 0.1 to 0.3 times as large as "d 1". If the ratio is less than 0.1, LLC matching of a circuit board (e.g., PSU) on which the transformer is mounted may be lost, and thus the operating frequency may rise, resulting in failure to control the circuit board. If the ratio exceeds 0.3, the efficiency of the transformer 101 may be lowered and oscillations may occur on the circuit board. However, this example is given assuming that a general PSU is used, and the present disclosure is not necessarily limited thereto, depending on the type of circuit in which the transformer is installed.

Therefore, referring to equations 1 and 2, the leakage inductance is affected by the coupling coefficient k, and the coupling coefficient is affected by the distance between the first coil unit and the second coil unit and the overlapping area therebetween. In the transformer 101 according to this embodiment, the coupling coefficient is reduced by controlling the separation distance between the first coil unit and the second coil unit so as to increase the leakage inductance, and the additional leakage inductance is ensured by shifting the receiving space of the first coil unit and the receiving space of the second coil unit from each other in the horizontal direction.

Therefore, the transformer according to this embodiment can be made thinner and can secure a high Lk value due to the above-described coupling structure of the bobbin unit, and is thus suitable for constituting a power supply unit of a flat panel television.

According to the transformer 101 of the above embodiment, at least in the region where the bobbin units B1 and B2 are surrounded by the core unit 110, the second receiving portion RP2 is provided on the first extending portion EP1 due to the coupling structure of the bobbin units B1 and B2, and the first receiving portion RP1 is provided below the second extending portion EP2, whereby the first receiving portion RP1 and the second receiving portion RP2 do not overlap each other at least partially in the horizontal direction. However, according to another embodiment, the space receiving the first coil unit 120 and the space receiving the second coil unit 130 may be parallel to each other.

While the present disclosure has been particularly shown and described with reference to exemplary embodiments thereof, these embodiments are presented for purposes of illustration only and not limitation, 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 described herein. For example, various configurations set forth in the embodiments may be modified and applied. Further, such modifications and differences in the applications should be construed as falling within the scope of the present disclosure as defined by the appended claims.

MODE OF THE INVENTION

Various embodiments have been described in terms of the best mode for carrying out the disclosure.

Claims

1. A transformer, comprising:

a core unit including an upper core and a lower core;

a first coil unit and a second coil unit disposed at least partially between the upper core and the lower core; and

a terminal bobbin coupled to one side of the second coil unit in a first direction,

wherein the first coil unit includes: a first coil; and a first coil frame having a first through hole through which the center leg of the core unit passes, the first coil frame receiving the first coil,

Wherein the second coil unit includes: a second coil; and a second bobbin having a second through hole, the second through hole receiving at least a portion of the first coil unit, the second bobbin receiving the second coil,

wherein, the terminal coil former includes: a plurality of first terminals spaced apart from each other in a second direction intersecting the first direction on one side of the terminal former oriented in the first direction; and an opening formed in the other side opposite to the one side in the first direction to allow one side of the second coil unit to be inserted thereinto, and

wherein both end portions of the first coil are led out from the first bobbin and are connected to first terminals different from each other among the plurality of first terminals of the terminal bobbin, respectively.

2. The transformer of claim 1, wherein the first bobbin comprises:

a first top plate; a bottom plate spaced apart from the first top plate in a third direction intersecting the first direction and the second direction; and a first side wall disposed between the top plate and the bottom plate, and

Wherein, first roof includes:

and an extraction groove allowing the two ends to be extracted to the first top plate through the extraction groove.

3. The transformer of claim 1, wherein the second bobbin comprises:

a second top plate; a second bottom plate spaced apart from the second top plate in a third direction intersecting the first direction and the second direction; and a second sidewall disposed between the second top plate and the second bottom plate.

4. A transformer according to claim 3, comprising:

a first portion provided on one side of the second bobbin in the first direction with respect to the second through hole; and

a second portion provided on the other side opposite to the first portion with respect to the second through hole,

wherein the second coil includes a plurality of wires disposed around the second via,

wherein one side of the plurality of wires extends to be disposed on the second portion,

wherein the other side of the plurality of wires extends such that both ends of the other side of the plurality of wires are disposed on the first portion,

wherein a first wire and a second wire of the plurality of wires at least partially overlap each other on the second portion, and

Wherein the second bobbin includes:

a recess portion at least partially overlapping with a region where the first wire and the second wire overlap each other on the second portion in the third direction.

5. The transformer of claim 4, wherein the second bobbin further comprises:

a second partition wall portion protruding downward from the second bottom plate in the third direction between the second through hole and the recess, and extending in the second direction.

6. A transformer, comprising:

a core unit including an upper core and a lower core;

a coil unit partially disposed in the core unit; and

a bobbin unit disposed between the core unit and the coil unit,

wherein the coil unit includes:

a first coil and a second coil arranged at least partially beside said first coil,

wherein the bobbin unit includes:

a first coil frame including a first receiving portion formed therein to receive the first coil; and

a second bobbin including a second receiving portion formed therein to receive the second coil,

wherein the first coil former includes a first extension portion extending from the first receiving portion toward the second coil former, and

Wherein the second receiving portion is disposed on the first extending portion.

7. The transformer of claim 6, wherein the first bobbin comprises:

a first top portion;

a first bottom portion disposed below the first top portion; and

a first intermediate portion disposed between the first top portion and the bottom portion, the first intermediate portion including a first through-hole defined by an inside surface thereof, an

Wherein the first extension is disposed on the first bottom portion.

8. The transformer of claim 6, wherein the second bobbin comprises:

a second top portion including a second through hole formed in a central portion thereof;

a second bottom portion disposed below the second top portion; and

a second intermediate portion disposed between the second top portion and the second bottom portion, and

wherein the first coil former is at least partially received in a recess defined by a lower surface of the second top portion and an inner side surface of the second intermediate portion.

9. The transformer of claim 6, wherein a shortest distance from a lower surface of the lower core to the first coil and a shortest distance from a lower surface of the lower core to the second coil are different from each other.

10. The transformer of claim 6, wherein the core unit comprises:

a first outer strut portion, a second outer strut portion, and a central strut portion disposed between the first outer strut portion and the second outer strut portion, an

Wherein a shortest distance between the first coil and the second coil is 0.1 times to 0.3 times a shortest distance from an outermost periphery of the first coil to one of the first outer leg portion and the second outer leg portion adjacent to the outermost periphery of the first coil.