Transformer and circuit board containing the same

Abstract

The present invention relates to a transformer and a circuit board including the same. One embodiment of the transformer according to the present invention includes a core part including a lower core part and an upper core part arranged on the lower core part, and a coil part including a first coil and a second coil and at least a part of which is arranged in the core part, and the lower core part includes a closed region overlapping with the upper core part in a first direction from the lower core part to the upper core part, and an open region extending from the closed region in a second direction perpendicular to the first direction and exposed to the outside of the closed region.

Description

[[Technical Field]]

[0001] The present invention relates to a transformer and a circuit board including the same. [[Background Art]]

[0002] By way of example, transformers are used in power supply devices for display devices. As the increase in size and thickness reduction of display devices accelerates, high power density and high efficiency characteristics are required along with thickness reduction of power supply devices.

[0003] In response to such demands for high density and high efficiency, high-frequency power supply devices (e.g., LLC resonant converters) have been proposed particularly as power supply devices for driving LED backlights that must have a wide voltage gain, and flat transformers have already been developed and put into use.

[0004] For example, in order to obtain desired resonance characteristics in an LLC resonant converter, a flat transformer can secure desired leakage inductance by increasing leakage flux through core shape design, without inserting a separate leakage layer or I-shaped core between a primary coil and a secondary coil.

[0005] Here, in order to obtain a stable output voltage over a wide voltage gain, it is necessary to reduce leakage inductance, and therefore, there is currently a need for a high-frequency planar transformer with small leakage inductance.

[0006] Particularly, for high-frequency driving of 160 to 300 kHz, it is necessary to adjust leakage inductance to be lower than that in conventional designs, and conventional EE-shaped cores have a problem of being unsuitable for high-frequency driving due to their high leakage inductance.

[0007] In order to realize lower and more precise leakage inductance than conventional designs, there is currently a need to modify conventional core structures. [[Summary of the Invention]] [Problems that the invention aims to solve]

[0008] The present invention aims to solve at least one of the problems of the prior art described above.

[0009] In particular, the objective is to provide a transformer that can precisely embody leakage inductance and reduce it compared to conventional transformers using EE-type cores.

[0010] Furthermore, the present invention aims to provide a transformer that can achieve thermal equilibrium by arranging a heat dissipation member in the applicable structure of the present invention to release the heat generated in the core and coil sections, thereby minimizing the temperature rise of the transformer. [Means for solving the problem]

[0011] One embodiment of the transformer according to the present invention includes a core portion including a lower core and a upper core disposed on the lower core, and a coil portion including a first coil and a second coil, at least a portion of which is disposed within the core portion, wherein the lower core includes a closed region that overlaps and closes with the upper core in a first direction toward the upper core from the lower core, and an open region that extends from the closed region in a second direction perpendicular to the first direction and is exposed outside the closed region.

[0012] In at least one embodiment of the present invention, a first midfoot and a pair of first outer feet are arranged in the closed region of the core, a second midfoot and a pair of second outer feet are arranged in the open region, and the first coil is wound around the first midfoot and the second midfoot.

[0013] Furthermore, in at least one embodiment of the present invention, the second metafoot is positioned at a distance of a set interval from the first metafoot, and the pair of second outer feet are positioned at a distance of a set interval from the pair of first outer feet.

[0014] In at least one embodiment of the present invention, the upper core includes a first metatarsal upper and a pair of first outer foot uppers, and the lower core includes a first metatarsal lower and a pair of first outer foot lowers.

[0015] Here, there may be a gap between the upper part of the first metatarsal and the lower part of the first metatarsal and / or between the pair of upper parts of the first outer foot and the lower parts of the first outer foot.

[0016] In at least one embodiment of the present invention, the upper part of the first metatarsal and the pair of upper parts of the first outer feet, and the lower part of the first metatarsal and the pair of lower parts of the first outer feet, each facing the second metatarsal and the pair of second outer feet, have end faces located on the same virtual plane.

[0017] Furthermore, in at least one embodiment of the present invention, the end portion on the second metatarsal side has a rounded shape.

[0018] In at least one embodiment of the present invention, the first coil is arranged in the closed region and the open region so as to surround the first midfoot and the second midfoot, and the second coil is arranged in the closed region so as to surround the first midfoot.

[0019] Here, a portion of the second coil may be positioned beyond the closed region.

[0020] In at least one embodiment of the present invention, the thickness of the first coil is greater than the thickness of the second coil.

[0021] Furthermore, in at least one embodiment of the present invention, the number of turns of the first coil is greater than the number of turns of the second coil.

[0022] In at least one embodiment of the present invention, the planar area of ​​the open region is smaller than the planar area of ​​the closed region.

[0023] One embodiment of the circuit board according to the present invention includes at least one transformer as described above.

[0024] Here, the transformer may be a transformer having a leakage inductance of 15 to 20 μH at a frequency of 160 to 300 kHz.

[0025] Further, other electronic components can be mounted on the circuit board together, and plated wires can be formed in a predetermined pattern on a surface of the circuit board for the electrical circuit configuration of the components. The circuit board constitutes an LLC resonant converter by way of example and can be included in a power supply device for a display.

[0026] At least one embodiment of the transformer according to the present invention comprises: a core portion including a lower core having a first lower middle leg and a second lower middle leg spaced apart from the first lower middle leg by a first separation distance, and an upper core disposed on the lower core and having an upper middle leg overlapping the first lower middle leg; and a coil portion including a first coil surrounding the first lower middle leg and the upper middle leg and disposed in a space of the first separation distance, and a second coil disposed outside the first coil and surrounding the first lower middle leg, the upper middle leg and the second lower middle leg, wherein at least parts of the first coil and the second coil are disposed inside the core portion, the lower core includes a closed region overlapping the upper core in a first direction directed from the lower core toward the upper core, and an open region extending from the closed region in a second direction perpendicular to the first direction and exposed from the upper core, the second lower middle leg is disposed with a first thickness along the second direction, and the first coil and the second coil are spaced apart from each other by a first separation distance not less than the first thickness.

[0027] The upper core is disposed in the closed region and includes a first upper outer leg and a second upper outer leg respectively spaced apart from the upper middle leg at predetermined intervals; the lower core is disposed in the closed region and includes a first lower outer leg and a second lower outer leg respectively spaced apart from the first lower middle leg at predetermined intervals, and the lower core is disposed in the open region and can include the second lower middle leg, and a third lower outer leg and a fourth lower outer leg respectively spaced apart from the second lower middle leg at predetermined intervals.

[0028] Further, in at least one embodiment of the present invention, in the closed region, the middle foot upper portion, the first outer foot upper portion and the second outer foot upper portion formed along the second direction are each arranged at a first length, and the first middle foot lower portion, the first outer foot lower portion and the second outer foot lower portion formed to have the first length along the second direction can be respectively overlapped corresponding to the middle foot upper portion, the first outer foot upper portion and the second outer foot upper portion.

[0029] In at least one embodiment of the present invention, in the open region, the second middle foot lower portion, the third outer foot lower portion and the fourth outer foot lower portion formed to have the first thickness are arranged, and each of the second middle foot lower portion, the third outer foot lower portion and the fourth outer foot lower portion can be arranged separated from the first middle foot lower portion, the first outer foot lower portion and the second outer foot lower portion by the first separation distance E1.

[0030] In at least one embodiment of the present invention, the core upper portion may comprise: a first groove portion arranged between the middle foot upper portion and the first outer foot upper portion and relatively recessed by the middle foot upper portion and the first outer foot upper portion; and a second groove portion arranged between the middle foot upper portion and the second outer foot upper portion and relatively recessed by the middle foot upper portion and the second outer foot upper portion.

[0031] The core lower portion comprises: a fourth groove portion arranged between the first middle foot lower portion and the first outer foot lower portion and relatively recessed by the first middle foot lower portion and the first outer foot lower portion; and a fifth groove portion arranged between the first middle foot lower portion and the second outer foot lower portion and relatively recessed by the first middle foot lower portion and the second outer foot lower portion, wherein the fourth groove portion and the fifth groove portion arranged in the closed region can be arranged to overlap with the first groove portion and the second groove portion respectively.

[0032] In at least one embodiment of the present invention, the open region may include a third groove that is recessed relative to the second midfoot portion, the first midfoot portion, the third outer foot portion, the first outer foot portion, and the second outer foot portion, separated by the first separation distance.

[0033] In at least one embodiment of the present invention, the first coil includes a first vertical coil portion that moves along the second direction and at least a portion of which penetrates the interior of the core portion, a first-1 horizontal coil portion that moves along a third direction perpendicular to the second direction and is located between the lower part of the second midfoot and the lower part of the first midfoot, and a first-2 horizontal coil portion located on the opposite side facing the first-1 horizontal coil portion, and the second coil may include a second vertical coil portion that moves along the second direction and at least a portion of which penetrates the interior of the core portion, a second-1 horizontal coil portion that moves along a third direction perpendicular to the second direction and is located outside the closed region adjacent to the lower part of the second midfoot, and a second-2 horizontal coil portion located on the opposite side facing the second-1 horizontal coil.

[0034] Here, the first horizontal coil section and the second horizontal coil section can be separated by the first separation distance.

[0035] Furthermore, the first vertical coil section and the second vertical coil section can be separated by a second separation distance that is smaller than the first separation distance.

[0036] The thickness of the first coil may be greater than the thickness of the second coil.

[0037] The number of turns of the first coil may be greater than the number of turns of the second coil.

[0038] In at least one embodiment of the present invention, the first separation distance may be 2 mm or more and less than 10 mm.

[0039] In at least one embodiment of the present invention, the planar area of ​​the open region may be smaller than the planar area of ​​the closed region.

[0040] In at least one embodiment of the present invention, the width of the first midfoot portion formed along a third direction perpendicular to the second direction and the width of the second midfoot portion formed along a third direction perpendicular to the second direction may be the same width.

[0041] In at least one embodiment of the present invention, the width of the second midfoot portion formed along a third direction perpendicular to the second direction may be greater than the width of the first midfoot portion formed along a third direction perpendicular to the second direction.

[0042] Here, the first midfoot substructure formed along a third direction perpendicular to the second direction is positioned with a first width, and the second midfoot substructure formed along the third direction is positioned with a second width, the second width may be 10% to 30% wider than the first width.

[0043] In at least one embodiment of the present invention, a heat dissipation member may be further arranged in the open region to cover a portion of the first coil and the second coil and a portion of the lower part of the core.

[0044] Here, the heat dissipation member may be positioned in direct contact with a portion of the coil portion, a portion of the upper part of the core, and the lower part of the core in the closed portion.

[0045] In at least one embodiment of the present invention, the heat dissipation member may be disposed in direct contact with one surface of the lower part of the core, the thickness surface and upper surface of the lower part of the second midfoot, the thickness surface and upper surface of the lower part of the third outer foot, the thickness surface and upper surface of the lower part of the fourth outer foot, and may be disposed in direct contact with the thickness surface of the first base of the upper part of the core, the thickness surface of the upper part of the midfoot, the thickness surface of the upper part of the first outer foot, and the thickness surface of the upper part of the second outer foot.

[0046] Here, the heat dissipation member may be formed from any one of the following: alumina (Al2O3), boron nitride (BN), silicon (Si), or a mixture thereof.

[0047] In at least one embodiment of the present invention, the heat dissipation member may have an insulating characteristic of 500 v / mm or more and a thermal conductivity of 3.0 W / mK or more. [Effects of the Invention]

[0048] According to the present invention, magnetic components suitable for high-frequency driving can be obtained.

[0049] In particular, the leakage inductance can be reduced more precisely compared to magnetic components with existing core structures. The leakage inductance, which is 25-30 μH when using conventional EE-type cores, can be reduced to less than that, preferably to 15-20 μH.

[0050] According to the present invention, by adjusting the separation distance between the first coil and the second coil without adjusting the size of the upper part of the middle leg and the lower part of the first middle leg, it is possible to induce a leakage inductance of a desired size while maintaining a constant value of the self-inductance (Lp), thereby increasing the DC bias of the transformer with the same self-inductance (Lp).

[0051] Furthermore, by arranging a heat dissipation member in the applicable structure of the present invention, the heat generated in the core and coil sections is released, minimizing the temperature rise of the transformer, thereby achieving thermal equilibrium of the transformer. [Brief explanation of the drawing]

[0052] [Figure 1] This figure shows a transformer as one embodiment of a magnetic component according to the present invention (the primary coil and its illustration are omitted in the drawing of Figure 1).

[0053] [Figure 2]Figure 1 is an exploded perspective view of the transformer (Figure 2 shows the primary and secondary coils together).

[0054] [Figure 3] This figure shows the core as shown in Figure 2.

[0055] [Figure 4] This figure shows the lower part of the core in Figure 3 {(a) shows the planar shape of the lower part of the core, and (b) shows the frontal shape of the lower part of the core}.

[0056] [Figure 5] This figure shows the top of the core in Figure 3 {(a) shows the planar shape of the top of the core in Figure 3, and (b) shows the right side shape of that top of the core}.

[0057] [Figure 6] This figure shows the first bobbin section as shown in Figure 2. [Figure 7] This figure shows the first bobbin section as shown in Figure 2.

[0058] [Figure 8] Figure 6 shows the front view and right side view of the first bobbin section.

[0059] [Figure 9] This figure shows the second bobbin section as shown in Figure 2. [Figure 10] This figure shows the second bobbin section as shown in Figure 2.

[0060] [Figure 11] This diagram shows the state in which the first bobbin section 40 and the second bobbin section 30 are joined together.

[0061] [Figure 12] This figure shows a first embodiment of the winding method for the secondary coil in the present invention.

[0062] [Figure 13]This figure shows a second embodiment of the winding method for the secondary coil in the present invention.

[0063] [Figure 14] This figure shows the relationship between the leakage inductance of the core and the gap according to an embodiment of the present invention.

[0064] [Figure 15] This is a perspective view of a transformer, which is one of the magnetic components according to another embodiment of the present invention.

[0065] [Figure 16] This is a plan view of a transformer according to another embodiment of the present invention.

[0066] [Figure 17] This is a side view of a transformer according to another embodiment of the present invention.

[0067] [Figure 18] This is a perspective view of the core portion in which the coil portion has been removed, according to another embodiment of the present invention.

[0068] [Figure 19] These are plan views of the upper and lower cores of a transformer according to another embodiment of the present invention.

[0069] [Figure 20] (a) is a graph showing the leakage inductance of a conventional transformer without an open region, and (b) is a graph showing the leakage inductance of a transformer with an open region according to another embodiment of the present invention.

[0070] [Figure 21] This graph compares the current density against inductance of a transformer according to another embodiment of the present invention and a conventional transformer.

[0071] [Figure 22]This is a plan view of a transformer according to yet another embodiment of the present invention.

[0072] [Figure 23] This is a plan view of a transformer according to yet another embodiment of the present invention.

[0073] [Figure 24] This is a side view of a transformer according to yet another embodiment of the present invention. [Modes for carrying out the invention]

[0074] While the present invention can be modified in various ways and has many embodiments, this document will describe specific embodiments illustrated with drawings. However, this should not be understood as limiting the present invention to specific embodiments, but rather as including all modifications, equivalents, or substitutes that fall within the spirit and technical scope of the present invention.

[0075] The suffixes “module” and “part” used herein are solely for the purpose of distinguishing between constituent elements in name and should not be interpreted as presupposing that they are physically or chemically separated or can be separated in that way.

[0076] Terms including ordinal numbers, such as "first," "second," etc., can be used to describe a variety of components, but the components are not limited to those terms. The terms are used solely for the purpose of distinguishing one component from another.

[0077] The term "and / or" is used to include all possible combinations of the items being referred to. For example, "A and / or B" includes all three cases: "A", "B", and "A and B".

[0078] When it is said that one component is "linked" or "connected" to another component, it should be understood that it may be directly linked or connected to the other component, but there may also be other components in between.

[0079] In the description of the embodiments, the statement that each layer (film), region, pattern, or structure is formed "on" or "under" the substrate, each layer (film), region, pad, or pattern includes all those that are formed directly or interposed by other layers. Furthermore, the criteria for "on" or "under" are, in principle, based on the state shown in the drawings for convenience, unless otherwise expressed in the attributes of each component or between them in the specification, and are used only to show the relative positional relationship between components for convenience, and should not be understood as limiting the actual position of the components. For example, "B on top" simply indicates that B is shown on top of A in the drawing, unless otherwise mentioned or unless A or B's attributes require A to be positioned on top of B. In actual implemented products, B may be positioned below A, and B and A may be positioned side by side.

[0080] Furthermore, the thickness and size of each layer (membrane), region, pattern, or structure in the drawings may be altered for clarity and convenience of explanation, and therefore do not directly reflect the actual size.

[0081] The terms used in this application are used solely to describe specific embodiments and are not intended to limit the invention. A singular expression includes plural expressions unless the context clearly indicates otherwise. In this application, terms such as “includes” or “having” are intended to specify the presence of features, figures, stages, operations, components, parts, or combinations thereof as described in the specification, and should be understood not to preemptively exclude the possibility of the presence or addition of one or more other features, figures, stages, operations, components, parts, or combinations thereof.

[0082] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as those generally understood by a person of ordinary skill in the art to which this invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having the meaning consistent with their meaning in the context of the relevant art, and should not be interpreted ideally or excessively formally unless expressly defined herein.

[0083] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0084] First, Figure 1 shows a transformer as an embodiment of a magnetic component according to the present invention (the primary coil 50 and secondary coil 60 are not shown in the drawing of Figure 1). Figure 2 is an exploded perspective view of the Transformer in Figure 1, Figure 3 is a diagram showing the core shown in Figure 2, Figure 4 is a diagram showing the lower core 20 of the core in Figure 3 {(a) shows the planar shape of the lower core 20, and (b) shows the frontal shape of the lower core 20}, Figure 5 is a diagram showing the upper core 10 of the core in Figure 3 {(a) shows the planar shape of the upper core 10 of the core in Figure 3 with the top overturned, and (b) shows the right side shape of the upper core 10}, Figures 6 and 7 are diagrams showing the first bobbin section 40 shown in Figure 2, Figure 8 is a frontal and right sideal view of the first bobbin section 40 in Figure 6, Figures 9 and 10 are diagrams showing the second bobbin section 30 shown in Figure 2, and Figure 11 is a diagram showing the state in which the first bobbin section 40 and the second bobbin section 30 are joined together.

[0085] The core shown in Figures 1 and 2 will be explained in detail with reference to Figures 3 to 5.

[0086] The core according to this embodiment includes a core upper part 10 and a core lower part 20, and the core upper part 10 is arranged on the core lower part 20 superimposed on the core lower part 20 in a first direction from bottom to top, forming a single core.

[0087] The lower core 20 includes an open region Ao and a closed region Ac. The closed region Ac is defined as a region that is covered and closed by overlapping with the upper core 10 in a first direction from the lower core 20 toward the upper core 10, and the open region Ao is defined as a region that extends from the closed region Ac in a second direction perpendicular to the first direction, and is not covered by the upper core 10 and is exposed outside the closed region Ac.

[0088] In this embodiment, the area of ​​the open region Ao on the plane is smaller than the area of ​​the closed region Ac on the plane.

[0089] The closed region Ac has a first metatarsal sub-section 21 and a pair of first outer foot sub-sections 22a and 22b positioned with the first metatarsal sub-section 21 in between.

[0090] Here, the corner portion of the lower part of the first metatarsal 21 has a rounded shape, and the lower parts of the first outer foot 22a and 22b have a angular shape at their corners (a rounded shape with a much smaller radius than the rounded shape of the first metatarsal), but are not limited to this.

[0091] The lower part of the first metatarsal 21 is separated from the lower parts of the first outer foot 22a and 22b by the distance of the grooves, as grooves r1 and r2 are formed on both sides.

[0092] In the open region Ao, a second metafoot 23 and a pair of second outer feet 24a and 24b are formed, with the second metafoot 23 positioned between them.

[0093] Here, as shown in Figure 4, the outer corner portion of the second metatarsal 23 has a rounded shape, and the corner portions of the second outer feet 24a and 24b all have a sharp shape (a rounded shape with a much smaller radius than the rounded shape of the outer corner portion of the second metatarsal), but are not limited to this.

[0094] The second metatarsal 23 also has grooves r1 and r2 formed on both sides, so that it is separated from the second outer feet 24a and 24b by a predetermined distance.

[0095] In the open region Ao, grooves r3 are formed between the lower part of the first midfoot 21 and the second midfoot 23, and between the lower parts of the first outer foot 22a, 22b and the second outer foot 24a, 24b. These grooves r3 cause the lower part of the first midfoot 21 and the second midfoot 23 to be separated by the width of the grooves.

[0096] The upper core 10 is positioned in the closed region Ac of the lower core 20, with the upper first metafoot 11 formed in the center, and a pair of upper first outer feet 12a and 12b positioned between the upper first metafoot 11.

[0097] The upper part 11 of the first midfoot also has grooves r4 and r5 formed on both sides, so that it is spaced apart from the upper parts 12a and 12b of the first outer feet by the width of the grooves. In this embodiment, the grooves r4 and r5 of the upper core 10 and the grooves r1 and r2 of the lower core have the same width w.

[0098] Furthermore, the upper part 11 of the first metafoot all have a rounded shape at their corners, and the upper parts 12a and 12b of the first outer foot all have a angular shape at their corners (a rounded shape with a much smaller radius than the rounded shape of the first metafoot), but are not limited to this.

[0099] In the upper core 10 and lower core 20, the closed region Ac has a symmetrical structure when assembled.

[0100] The upper core 10 in Figure 5 is the shape of the upper core 10 shown in Figure 3 when it is inverted {Figure 5(a)} and the shape of its right side {Figure 5(b)}. In the assembled state shown in Figure 3, the upper first midfoot 11 of the upper core 10 is positioned on the lower first midfoot 21, and the upper first outer foot 12b and lower first outer foot 12a of Figure 5 are positioned on the lower first outer foot 22b and upper first outer foot 22a of Figure 4, respectively.

[0101] Preferably, the upper core 10 is positioned to have a predetermined gap above the lower core 20. For this purpose, gaps may be formed between the upper and lower first metatarsal sections 11, 21 and / or between the upper and upper first lateral foot sections 12a, 12b, 22a, 22b.

[0102] As the upper core 10 is positioned on the lower core 20, the upper first metatarsal 11 and the lower first metatarsal 21 form the first metatarsal, and the upper first lateral foot 12a, 12b and the lower first lateral foot 22a, 22b form the first lateral foot.

[0103] As shown in Figures 3 to 5, with the upper core 10 positioned on the lower core 20, the upper first metafoot 11 and the pair of upper first outer feet 12a, 12b, and the lower first metafoot 21 and the pair of lower first outer feet 22a, 22b, which face the second metafoot 23 and the pair of second outer feet 24a, 24b respectively, may have their end faces located on the same virtual plane P.

[0104] In this core structure, the primary coil 50 and the secondary coil 60 are arranged inside the core. The primary coil 50 is wound to surround the first mid-columns 11, 21 and the second mid-columns 23 and is positioned in the closed region Ac and the open region Ao of the core. The secondary coil 60 is wound to surround only the first mid-columns 11, 21 and is positioned in the closed region Ac. Here, a portion of the secondary coil 60 may extend beyond the closed region Ac into the open region Ao. In this embodiment, the total thickness of the primary coil 50 may be greater than the total thickness of the secondary coil 60, but the thickness of a single secondary coil 60 is greater than that of a single primary coil 50.

[0105] In this embodiment, the number of turns of the primary coil 50 is greater than the number of turns of the secondary coil 60.

[0106] In the closed region Ac, the primary coil 50 and the secondary coil 60 are linked, while in the open region Ao, the two coils 50 and 60 are not linked. Voltage conversion is achieved in the closed region Ac where the two coils 50 and 60 are linked, and in the open region Ao, which is a non-linked region, the leakage inductance generated in the closed region Ac is canceled out via the leakage flux, thereby inducing a leakage inductance of the desired size. Similar to conventional EE-type cores, the leakage inductance generated relatively large in the closed region Ac is canceled out in the open region Ac, and the overall leakage inductance is adjusted to be low, thereby securing a lower leakage inductance than conventional designs.

[0107] In the transformer according to this embodiment, the leakage inductance can be adjusted by the magnitude of the gap between the lower part 21 of the first middle leg and the second middle leg 23 and / or between the lower parts 22a, 22b of the first outer legs and the second outer legs 24a, 24b, as will be described later.

[0108] On the other hand, in this embodiment, the bobbin includes a first bobbin section 40 and a second bobbin section 30, and as shown in Figure 11, the first bobbin section 40 is inserted below the second bobbin section 30 during assembly.

[0109] In this embodiment, the first bobbin section 40 provides a primary coil housing section and a secondary coil housing section, and the second bobbin section 30 provides terminal sections for the primary coil 50 and the secondary coil 60.

[0110] The first bobbin section 40 includes an upper plate 41, a middle plate 42, and a lower plate 43. A secondary coil housing section is formed between the upper plate 41 and the middle plate 42, and a primary coil housing section is formed between the middle plate 42 and the lower plate 43.

[0111] Such a first bobbin section 40 has a first midfoot through-hole 44 that penetrates from the upper plate 41 to the lower plate 43, and the lower plate 43 has a second midfoot accommodating groove 47 that extends from the first midfoot through-hole 44 toward the primary terminal section 32 described later to accommodate the second midfoot 23.

[0112] Between the upper plate 41 and the middle plate 42, an upper rim 45 is formed so as to surround the upper part of the first midfoot through hole 44, and between the middle plate 42 and the lower plate 43, a lower rim 46 is formed so as to surround the lower part of the first midfoot through hole 44 and the second midfoot housing groove 47.

[0113] The primary coil housing includes a space formed to surround the lower rim 46, and the secondary coil housing includes a space formed to surround the upper rim 45, with the primary coil 50 and the secondary coil 60 being arranged in each of these spaces.

[0114] A pair of core guides 41a and 41b are provided on the upper plate 41 of the first bobbin section 40, projecting upward. When the first bobbin section 40 is inserted into the second bobbin section 30, the pair of core guides 41a and 41b have a structure that protrudes higher above the upper surface of the second bobbin section 30, and the upper part of the core 10 is positioned between the pair of core guides 41a and 41b. The pair of core guides 41a and 41b facilitate the positioning of the core relative to the bobbin (or coil).

[0115] The second bobbin section 30 includes a primary terminal section 32 and a secondary terminal section 33 on both sides, and includes a body section 31 between the terminal sections 32 and 33.

[0116] The primary terminal section 32 has a first pin section 32c on both sides into which terminal pins connected to the terminals of the primary coil 50 are inserted and fixed, and a first coil wire groove 32a is formed therein, and a first wiring projection 32b is formed therein for wiring the coil wire (hereinafter referred to as terminal wire) connected to the terminals of the primary coil 50.

[0117] Multiple second coil wire grooves 33a are arranged alternately in a row in the secondary terminal section 33, and a second wiring projection 33b for wiring the coil wire is formed on the upper surface.

[0118] In this embodiment, the secondary coil 60 includes four individual coil wires, each of which forms one turn relative to the secondary coil 60. As a result, the secondary terminal section 33 in this embodiment includes a total of eight second coil wire grooves 33a. Here, each secondary coil 60 can be drawn out through the second coil wire groove 33a and come into contact with a separate terminal pin (not shown).

[0119] Furthermore, the second bobbin section 30 has a non-through groove, an intermediate plate receiving groove 36, at its lower part for accommodating the intermediate plate 42 (or lower plate 43) of the first bobbin section 40. The second bobbin section 30 also has a through groove, an upper plate receiving through groove 34, for accommodating the upper plate 41 of the first bobbin section 40.

[0120] Here, multiple fixing protrusions 36a are formed on the peripheral wall of the intermediate plate housing groove 36 in order to prevent the intermediate plate 42 (or lower plate 43) of the first bobbin portion 40 from detaching downward while it is housed there.

[0121] Furthermore, a first terminal wire passage 42a is formed in the middle plate 42 of the first bobbin section 40 through which the terminal wires of the primary coil 50 housed in the primary coil housing section pass, and a second terminal wire passage 35 corresponding to the first terminal wire passage 42a is formed in the second bobbin section 30 so that the terminal wires of the primary coil 50 pass through the primary terminal section 32. On both sides of the first terminal wire passage 42a of the middle plate 42 of the first bobbin section 40, protrusions 42b and 42c are formed for fixing the coil wires of the primary coil 50.

[0122] In this embodiment, the peripheral wall 34a of the upper plate housing through groove 34 is arranged to surround the secondary coil housing space. The secondary coil 60 is housed in the secondary coil housing space formed in the space between the upper rim 45 of the first bobbin portion 40 and the peripheral wall 34a of the upper plate housing through groove 34.

[0123] Here, as shown in Figure 9, the peripheral wall 34a of the upper plate housing through groove 34 on the secondary terminal section 33 side has a low or almost non-existent wall height, providing a passage for each coil wire of the secondary coil 60 toward the secondary terminal section 33. The inclined surface 37 is formed so that it gradually widens and gradually increases in height toward the secondary terminal section 33, thereby increasing the degree of freedom in terminal wire arrangement by acting as a guide and support for the terminal wire arrangement of the secondary coil 60, and making wiring work easier.

[0124] In this embodiment, the width of the first bobbin portion 40 is the same as or smaller than the width of the body portion 31 of the second bobbin portion 30. Therefore, when the first bobbin portion 40 is coupled to the second bobbin portion 30, the first bobbin portion 40 does not protrude outside the body portion 31 of the second bobbin portion 30.

[0125] Furthermore, the width of the body portion 31 of the second bobbin portion 30 is the same as or less than the distance between the inner wall surfaces of the first outer legs 12a, 12b, 22a, 22b, and when the first bobbin portion 40 and the second bobbin portion 30 are joined together, the height of the bobbin portion located inside the core is the same as or less than the height of the groove formed between the first middle legs 11, 21 and the first outer legs 12a, 12b, 22a, 22b ("r1 height + r4 height" or "r2 height + r5 height"). Therefore, the bobbins are aligned and arranged inside the core. In other words, when the primary coil 50 and the secondary coil 60 are arranged inside the first bobbin portion 40 and the second bobbin portion 30, the combined body is completely housed inside the cores 10 and 20.

[0126] On the other hand, Figure 12 shows an example of the winding method for the secondary coil 60 in the present invention, and Figure 13 shows a comparative example of the winding method for the secondary coil 60 in the present invention.

[0127] The diagram shown at the top of Figure 12 shows the wiring of the secondary coil 60 according to the first embodiment on the second bobbin portion 30, while the diagram shown at the bottom shows the wiring diagram in which each coil wire constituting the secondary coil 60 is connected to the second terminal pin.

[0128] TIFF0007915229000001.tif17170

[0129] TIFF0007915229000002.tif10170

[0130] TIFF0007915229000003.tif25170

[0131] The winding method of the secondary coil 60 in this embodiment has the effect of improving the current imbalance between the coil wires of the secondary coil 60 compared to the comparative example, because the total length of the secondary output winding is made the same. Furthermore, the wiring and structure of this secondary coil 60 can lower the resistance to the applied current and increase the efficiency of the transformer, and it has the effect of suppressing the heat generated in the transformer by reducing the heat generated by the resistance.

[0132] On the other hand, Figure 14 shows the relationship between the leakage inductance of a core according to an embodiment of the present invention {indicated as "open core" in Figure 14(b)} and the distance (r3 distance) between the lower part 21 of the first mid-pin and the second mid-pin 23. As shown in Figure 14, in the core according to the embodiment of the present invention, the leakage inductance gradually decreases at a large rate of change as the distance increases, and it is possible to reach a leakage inductance lower than that of a conventional EE-type core.

[0133] Therefore, by adjusting the spacing between the first and second mid-range pins, the leakage inductance can be adjusted more precisely, making it possible to adjust the leakage inductance to 15-20 μH in high-frequency drives of 160-300 kHz.

[0134] Figure 15 is a perspective view of a transformer, which is one of the magnetic components according to another embodiment of the present invention; Figure 16 is a plan view of a transformer according to another embodiment of the present invention; Figure 17 is a side view of a transformer according to another embodiment of the present invention; Figure 18 is a perspective view of a core portion with the coil portion removed according to another embodiment of the present invention; and Figure 19 is a plan view of the upper and lower core portions of a transformer according to one embodiment.

[0135] Referring to Figures 15 to 19, another embodiment of the present invention, the transformer 1, includes a core portion 100 and a coil portion 200.

[0136] The core portion 100 includes an upper core portion 110 and a lower core portion 120, and the upper core portion 110 is positioned on the lower core portion 120 superimposed on the lower core portion 120 in a first direction (z-axis direction) from bottom to top.

[0137] Specifically, referring to Figures 18 and 19(b), the core upper 110 includes a midfoot upper 111 that protrudes from one surface of the first base and is located in the central region of the first base, and first and second outer foot uppers 112a and 112b that are located on both sides of the midfoot upper 111 at a predetermined distance apart.

[0138] The first base may be formed to have a predetermined width along the third direction (X-axis direction). The width of the first base will be referred to as the total width w. Since the second base of the lower core 120, which will be described below, is arranged to overlap with the upper core 110, the total width of the second base may also be formed to the same total width w. Since the upper midfoot 111 and the first and second upper outer foot 112a and 112b are provided protruding from the first base, the upper core 110 may have fourth and fifth grooves r4 and r5 that are formed to be recessed relative to the upper midfoot 111 and the first and second upper outer foot 112a and 112b.

[0139] The fourth groove r4 may be located between the upper midfoot 111 and the upper first outer foot 112a, and the fifth groove r5 may be located between the upper midfoot 111 and the upper second outer foot 112b. The fourth and fifth grooves r4 and r5 may be located with a fourth width W4 and a fifth width W5, respectively. The fourth width W4 and the fifth width W5 may be formed with the same width, but are not limited to this, and may be formed with different widths.

[0140] On the other hand, the first base of the core upper 110 may be formed to a first length K1 along the second direction (Y-axis direction). Here, the lengths of the midfoot upper 111, the first outer foot upper 112a, and the second outer foot upper 112b may be formed to the same length as the first length K1, but are not limited thereto.

[0141] Referring to Figures 18 and 19(a), the core lower section 120 protrudes from one surface of the second base and includes a first midfoot lower section 121 and a second midfoot lower section 123 located in the central region of the second base. The first midfoot lower section 121 and the second midfoot lower section 123 may be spaced apart at a predetermined interval in a second direction (Y-axis direction). Here, the distance between the first midfoot lower section 121 and the second midfoot lower section 123 may be a first separation distance E1. A third groove r3, described later, may be formed between the first midfoot lower section 121 and the second midfoot lower section 123.

[0142] The core lower section 120 may have first and second outer foot lower sections 122a and 122b positioned on either side of the first midfoot lower section 121 at predetermined intervals, and third and fourth outer foot lower sections 124a and 124b positioned on either side of the second midfoot lower section 123 at predetermined intervals. The distance between the first midfoot lower section 121 and the first outer foot lower section 122a may be a first width W1, and the distance between the first midfoot lower section 121 and the second outer foot lower section 122b may be a second width W2. Considering the ease of molding the core lower section 120, the distance between the second midfoot lower section 123 and the third outer foot lower section 124a may also be a first width W1. The distance between the second midfoot lower section 123 and the fourth outer foot lower section 124b may also be a second width W2.

[0143] The second base, like the first base, may be formed to have a full width w along the third direction (X-axis direction). The core lower part 120 may have first and second grooves r1, r2 which are formed to be recessed relative to the first midfoot lower part 121 and the first and second outer foot lower parts 122a, 122b and the second midfoot lower part 123 and the third and fourth outer foot lower parts 124a, 124b.

[0144] The first groove r1 may be located between the first midfoot lower section 121 and the first lateral foot lower section 122a, and between the second midfoot lower section 123 and the third lateral foot lower section 124a. The second groove r2 may be located between the first midfoot lower section 121 and the second lateral foot upper section 112b, and between the second midfoot lower section 123 and the fourth lateral foot lower section 124b.

[0145] The first and second grooves r1 and r2 may be arranged to have a first width W1 and a second width W2, respectively. The first width W1 and the second width W2 may be formed to be the same width, but are not limited to this, and may be formed to have different widths.

[0146] Furthermore, the widths of the first and second grooves r1 and r2 may be formed to be the same width as the widths of the fourth and fifth grooves r4 and r5, respectively, but are not limited to this. In this embodiment, the cases in which the widths of the first and second grooves r1 and r2 correspond to the widths of the fourth and fifth grooves r4 and r5, respectively, are illustrated and explained.

[0147] On the other hand, the second base of the lower core 120 may be formed with a third length K3 along the second direction (Y-axis direction). Here, the region of the third length K3 may be the sum of the first length K1 and the second length K2. When the lower core 120 is joined to the upper core 110, the region of the first length K1 is the region where the lower core 120 and the upper core 110 overlap, and the region of the second length K2 may be the region where the lower core 120 is exposed from the upper core 110.

[0148] In the region of second length K2, a first thickness G1 of the second midfoot lower part 123 formed along the second direction (Y-axis direction) and a first separation distance E1 formed along the second direction (Y-axis direction) may be located. In addition, in the region of second length K2, a second thickness G2 of the third and fourth outer foot lower parts 124a, 124b and a second separation distance E2, which is the separation distance between the first and second outer foot lower parts 122a, 122b and the third and fourth outer foot lower parts 124a, 124b may be located.

[0149] In this embodiment, the lower core 120, formed with ease of molding in mind, is shown and described in detail when the first thickness G1 and the second thickness G2, and the first separation distance E1 and the second separation distance E2 are the same. Here, the example is described when the first thickness G1 and the second thickness G2 are the same, but it is not limited to this, and the first thickness G1 and the second thickness G2 can be arranged to be different from each other. Similarly, the example is described when the first separation distance E1 and the second separation distance E2 are the same, but it is not limited to this, and the first separation distance E1 and the second separation distance E2 can be arranged to be different from each other.

[0150] The first lower metatarsal portion 121, the first lower lateral foot portion 122a, and the second lower lateral foot portion 122b may be formed to the same length as the first length K1, corresponding to the upper metatarsal portion 111, the first upper lateral foot portion 112a, and the second upper lateral foot portion 112b, respectively, but are not limited thereto.

[0151] In the region of second length K2, the second midfoot lower section 123, the third outer foot lower section 124a, and the fourth outer foot lower section 124b may be located. In addition, in the region of second length K2, a first separation distance E1 may be formed between the second midfoot lower section 123 and the first midfoot lower section 121, a second separation distance E2 may be formed between the third outer foot lower section 124a and the first outer foot lower section 122a, and a second separation distance E2 may be formed between the second outer foot upper section 112b and the fourth outer foot lower section 124b. A third groove r3 may be located in the first separation distance E1 and the second separation distance E2, which is recessed relative to the second base and the midfoot and outer foot protruding from the second base.

[0152] Thus, the core portion 100 is arranged such that the length of the upper core portion 110 and the length of the lower core portion 120 are different, and includes a closed region Ac where the upper core portion 110 and the lower core portion 120 overlap each other, and an open region Ao where the lower core portion 120 is exposed by the upper core portion 110.

[0153] In this embodiment, the area of ​​the open region Ao on the plane may be smaller than the area of ​​the closed region Ac on the plane. In other words, the region with the second length K2 may be smaller than the region with the first length K1.

[0154] For example, the closed region Ac is a region that is closed by being covered by overlapping with the upper core 10 in a first direction (z-axis direction) from the lower core 120 to the upper core 110, and the open region Ao is a region that extends from the closed region Ac in a second direction perpendicular to the first direction (z-axis direction), and is not covered by the upper core 10 and may be a region exposed outside the closed region Ac.

[0155] The closed region Ac is located in a region of first length K1, and may be arranged such that the first lower part 121 and upper part 111 of the metatarsal region overlap, the first upper part 112a and first lower part 122a of the outer foot overlap, and the second upper part 112b and second lower part 122b of the outer foot overlap. Furthermore, the relatively recessed first and second grooves r1 and r2 and the fourth and fifth grooves r4 and r5 may be arranged to overlap.

[0156] The open region Ao is located in a region of second length K2, and the second lower midfoot 123, third lower lateral foot 124a, and fourth lower lateral foot 124b are located therein. A third groove r3 may be located between the second lower midfoot 123, third lower lateral foot 124a, and fourth lower lateral foot 124b and the closed region Ac.

[0157] Furthermore, the first and second grooves r1 and r2 may have areas that do not overlap with the fourth and fifth grooves r4 and r5 located in the open region Ao. Hereafter, the areas where the first and second grooves r1 and r2 overlap with the fourth and fifth grooves r4 and r5 will be referred to as the fourth and fifth grooves r4 and r5, and the areas where the first and second grooves r1 and r2 do not overlap with the fourth and fifth grooves r4 and r5 will be referred to as the first and second grooves r1 and r2.

[0158] Referring also to Figures 15-19, the coil section 200 includes a first coil 210 and a second coil 220 that penetrate the interior of the core section 100. Here, for the sake of simplicity, the first coil 210 and the second coil 220 will be described as having a square loop shape.

[0159] The first coil 210 may be arranged in a shape that surrounds the region where the upper midfoot 111 and the lower midfoot 121 overlap. Specifically, the first coil 210 includes a first vertical coil section 213 that extends along the Y-axis and is positioned in the fourth and fifth grooves r4 and r5, a first-first horizontal coil section 215 that extends along the X-axis and is positioned between the lower second midfoot 123 and the lower first midfoot 121, and a first-second horizontal coil section 218 positioned on the opposite side facing the first-first horizontal coil section 215.

[0160] The first-first horizontal coil portion 215 of the first coil 210 may be positioned in a third groove r3 formed in the open region Ao. Thus, the first-first horizontal coil portion 215 of the first coil 210 may be positioned in a region of second length K2 that does not overlap with the upper core 110. Therefore, the third groove r3 may be formed to a width that can accommodate the forming width of the first-first horizontal coil portion 215 of the first coil 210. For example, a third groove r3 positioned at a first separation distance E1 may be formed to a thickness in the range of 3 mm to 20 mm along the Y-axis.

[0161] Here, the third groove r3 is determined by the wire diameter of the secondary coil in the Y-axis direction. This requires a thickness of at least 3 mm to apply a secondary coil suitable for the allowable current. If it exceeds 20 mm, core losses will increase, and the system will not be able to perform optimally.

[0162] The first vertical coil portion 213 of the first coil 210 is located in the fourth and fifth grooves r4 and r5, where the upper core 110 and the lower core 120 are superimposed, and a portion of it may be located in the region where the first and second grooves r1 and r2 and the third groove r3 overlap in order to connect to the first horizontal coil portion 215. In other words, a portion of the first vertical coil portion 213 may be located in the closed region Ac, and another portion may be located in the open region Ao.

[0163] The first-to-second horizontal coil portion 218 of the first coil 210 may be located outside the closed region Ac, that is, outside the region of first length K1. That is, the first vertical coil portion 213 may be located outside the first length region K1, the second length region K2, and the region of first length K1. Here, the region of first length K1 is the external region located on the opposite side of the region of second length K2 within the region of first length K1.

[0164] The second coil 220 may be arranged in a shape that surrounds the region where the upper midfoot 111 and the lower first midfoot 121 overlap and the lower second midfoot 123. Specifically, the second coil 220 includes a second vertical coil section 223 that extends in the Y-axis direction and is located in the fourth and fifth grooves r4 and r5, a second-first horizontal coil section 225 that extends in the X-axis direction and is located outside the closed region Ac adjacent to the lower second midfoot 123, and a second-second horizontal coil section 228 located on the opposite side facing the second-first horizontal coil section 225.

[0165] The second-first horizontal coil section 225 of the second coil 220 may be located outside the closed region Ac. In other words, the second-first horizontal coil section 225 may be located outside a region of second length K2 adjacent to the second midfoot lower section 123. Therefore, the second-first horizontal coil section 225 may be located with a first separation distance D1 from the first-first horizontal coil section 215.

[0166] The first separation distance D1 may be greater than or equal to the thickness formed in the Y-axis direction of the second mid-foot lower part 123, which is arranged in the second-first horizontal coil section 225 and the first-first horizontal coil section 215. For example, the first separation distance D1 may be 2 mm or more and less than 15 mm. If the first separation distance D1 is less than 2 mm, the first thickness G1 of the second mid-foot lower part 123 formed in the Y-axis direction becomes small, causing magnetic field loss and degrading the performance of the second mid-foot lower part 123. If it is 15 mm or more, the separation distance from the first coil becomes large, which may cause loss in the second coil. Therefore, it is preferable that the first separation distance D1 be 2 mm or more and less than 15 mm.

[0167] The second vertical coil portion 223 of the second coil 220 is located in the fourth and fifth groove portions r4 and r5, where the upper core 110 and the lower core 120 are superimposed. A portion of this area may be located in the region where the first and second groove portions r1 and r2 and the third groove portion r3 overlap, in order to connect to the second-first horizontal coil portion 225. Furthermore, the remaining area may be located outside the closed region Ac in order to connect to the second-first horizontal coil portion 225.

[0168] In other words, a portion of the second vertical coil section 223 may be located in the closed region Ac, another portion in the open region Ao, and yet another portion in the region outside the open region Ao. Thus, the second coil 220 may have a second vertical coil section 223 that is longer than the region of the first length K1 and the region of the second length K2.

[0169] Here, the first vertical coil section 213 and the second vertical coil section 223 can also be positioned in the fourth and fifth groove sections r4, r5, or in the first and second groove sections r1, r2, with the aforementioned first separation distance D1. Alternatively, they can be positioned with a second separation distance D2 that is different from the first separation distance D1. The reason why the separation distances between the first vertical coil section 213 and the second vertical coil section 223 are different is that there is a limit to how much the overall width w of the core section 100 can be increased in order to realize a light, thin, and compact transformer. Therefore, the aforementioned second separation distance D2 may be smaller than the first separation distance D1.

[0170] The second-second horizontal coil portion 228 of the second coil 220 may be located outside the closed region Ac, that is, outside the region of third length K3.

[0171] On the other hand, the first coil 210 and the second coil 220 may be formed to have different thicknesses. For example, the thickness of the first coil 210 may be greater than the thickness of the second coil 220. In order to form the first coil 210 to be thicker than the second coil 220, the number of turns of the first coil 210 can be greater than the number of turns of the second coil 220.

[0172] In the closed region Ac, the first coil 210 and the second coil 220 can be linked, while in the open region Ao, the first coil 210 and the second coil 220 cannot be linked. In the closed region Ac, where the first coil 210 and the second coil 220 are linked, voltage conversion is achieved, and in the open region Ao, which is a non-linked region, the leakage flux cancels out the leakage inductance generated in the closed region Ac, thereby inducing a leakage inductance of a desired magnitude.

[0173] In this way, by adjusting the first separation distance D1, which is the separation distance between the first coil 210 and the second coil 220, without adjusting the size of the upper part 111 and the lower part 121 of the first mid-foot, it is possible to induce a leakage inductance of a desired size while maintaining a constant value of the self-inductance (Lp).

[0174] Therefore, the transformer 1 of this embodiment can adjust the leakage inductance by adjusting the magnitude of the gap between the first midfoot lower part 121 and the second midfoot lower part 123 and / or between the first outer foot lower part 122a and the third outer foot lower part 124a and / or between the second outer foot upper part 122b and the fourth outer foot lower part 124b.

[0175] Figure 20(a) is a graph showing the leakage inductance of a conventional transformer without an open region, Figure 20(b) is a graph showing the leakage inductance of a transformer with an open region according to another embodiment of the present invention, and Figure 21 is a graph comparing the current density of the inductance of a transformer according to one embodiment and a conventional transformer.

[0176] Referring to Figures 20(a) and 21, it can be seen that transformers with only closed regions Ac, like conventional EE-type cores, generate a large leakage inductance due to the closed regions Ac. It can be seen that a leakage inductance of 3.1A occurs in the m1 region shown in the graph.

[0177] On the other hand, referring to Figures 20(b) and 21, it can be seen that by canceling out in the open region Ao and adjusting the leakage inductance to a lower level, a lower leakage inductance than conventional methods can be secured. It can be seen that a leakage inductance of 3A occurs in the m1 region shown in the graph.

[0178] When the same current is supplied to both a conventional transformer and the transformer of this embodiment, the transformer of this embodiment has a flux flow that cancels out between the first mid-foot lower section 121 and the second mid-foot lower section 123, so even with a higher current flow, the flux and current density values ​​induced in the coil section 200 can be lower. This is because the core section 100 can be prevented from saturating by further accommodating the flux density in the open region Ao.

[0179] Therefore, it can be seen that the open region Ac plays a role in additionally storing energy, thereby increasing the power capacity. In other words, it can be seen that the transformer according to this embodiment has improved DC-bias performance compared to conventional cores.

[0180] Therefore, the transformer 1 according to one embodiment can induce a desired leakage inductance while maintaining a constant self-inductance (Lp) value by adjusting the first separation distance D1, which is the separation distance between the first coil 210 and the second coil 220, without adjusting the size of the upper part 111 or the lower part 121 of the first mid-leg. In other words, the DC bias of the transformer can be increased with the same self-inductance (Lp).

[0181] Figure 22 is a plan view showing a transformer according to yet another embodiment of the present invention.

[0182] Figure 22 omits the explanation of the midfoot and, for the sake of simplicity, refers to Figures 15 to 21 for explanation.

[0183] Referring to Figure 22, a transformer 2 according to another embodiment of the present invention may include a first midfoot lower section 121 having a first width Q1 formed along the X-axis direction and a second midfoot lower section 123 having a second width Q2 formed along the X-axis direction.

[0184] The second width Q2 can be formed to be 10% to 150% wider than the first width Q1.

[0185] Referring to Figure 16 for easy comparison with the previous embodiment, the first midfoot lower section 121 and the second midfoot lower section 123 can be arranged to have the same first width Q1. The first midfoot lower section 121 and the second midfoot lower section 123 having the same first width Q1 can be easily molded.

[0186] In another embodiment, the transformer 2 has a first midfoot lower section 121 and a second midfoot lower section 123 formed with different widths, which allows the open region Ao to additionally store energy and increase the high power capacity, thereby additionally accommodating magnetic flux density in the open region Ac and preventing the core section 100 from saturating.

[0187] Therefore, in the other embodiment, the transformer 2 can induce a desired leakage inductance while maintaining a constant self-inductance (Lp) by arranging the first mid-leg lower section 121 and the second mid-leg lower section 123 with different widths from each other. That is, the DC bias of the transformer can be increased with the same self-inductance (Lp).

[0188] Figure 23 is a plan view of a transformer according to yet another embodiment, and Figure 24 is a side view of a transformer according to yet another embodiment.

[0189] Figures 23 and 24 omit the explanation of the midfoot and, for the sake of simplicity, refer to Figures 15 to 22 for explanation.

[0190] Referring to Figures 23 and 24, the transformer 3 according to yet another embodiment may include a heat dissipation member 800 positioned in the open region Ao. The heat dissipation member 800 can cover a portion of the first coil 2100 and the second coil 220 and a portion of the lower core 120.

[0191] The heat dissipation member 800 is placed in the open region Ao and may be placed in a region of second length K2. The second middle leg lower part 123, the third outer leg lower part 124a, the fourth outer leg lower part 124b, and the third groove r3 may be placed in the region of second length K2. In addition, the second vertical coil portion 223 and the first vertical coil portion 213 may be placed in the region where the first and second grooves r1, r2 and the third groove r3 overlap.

[0192] Therefore, the heat dissipation member 800 may be positioned to cover the second vertical coil section 223 and the first vertical coil section 213, and to cover the lower part of the second middle leg 123, the lower part of the third outer leg 124a, the lower part of the fourth outer leg 124b, and the third groove r3.

[0193] Here, the heat dissipation member 800 is positioned not only to cover the aforementioned configuration but also to be in direct contact with it, thereby enabling it to radiate the thermal energy generated in the core portion 100 and the coil portion 200 to the outside. In other words, the heat dissipation member 800 can be positioned to be in direct contact with the coil portion 200, the upper core portion 110, and the lower core portion 120.

[0194] Specifically, the heat dissipation member 800 may be positioned to directly contact the upper and side surfaces of the second vertical coil section 223 and the first vertical coil section 213. Alternatively, the heat dissipation member 800 may be positioned to directly contact one surface of the lower core section 120 located in the open region Ao.

[0195] Specifically, the heat dissipation member 800 may be positioned to directly contact one surface of the second base of the core lower part 120, and to directly contact the thickness surface and top surface of the second middle leg lower part 123, the thickness surface and top surface of the third outer leg lower part 124a, and the thickness surface and top surface of the fourth outer leg lower part 124b, which are projecting from one surface of the second base.

[0196] Furthermore, it may be positioned to be in direct contact with the side surface of the upper core 110 located at the interface P between the first region of length K1 and the second region of length K2.

[0197] More specifically, the core upper part 110 can be positioned to be in direct contact with the thickness surface of the first base, the thickness surface of the middle leg upper part 111, the thickness surface of the first outer leg upper part 112a, and the thickness surface of the second outer leg upper part 112b, where the core upper part 110 is exposed at the interface P. Also, at the interface P, the thickness surfaces of the first middle leg lower part 121, the first outer leg lower part 122a, and the second outer leg upper part 122b, which overlap with the middle leg upper part 111, the first outer leg upper part 112a, and the second outer leg upper part 112b, are exposed, so they can be positioned to be in direct contact with the heat dissipation member 800.

[0198] Therefore, the heat dissipation member 800, which is positioned in direct contact with the aforementioned components, is in direct contact not only with the open region Ao but also with a portion of the upper core 110 and lower core 120 at the interface P, thereby efficiently radiating the thermal energy generated in the closed region Ac to the outside.

[0199] The heat dissipation member 800 is placed in the open region Ao and may be positioned so as to have a thickness parallel to the other surface of the first base of the first coil 210. Here, the other surface of the first base is the surface facing one surface of the first base, and the one surface of the first base is the surface on which the first outer leg upper part 112a, the second outer leg upper part 112b, and the middle leg upper part 111 are formed.

[0200] In another embodiment, the heat dissipation member 800 may be formed such that its thickness exposes the upper surface of the third outer leg lower portion 124a, the upper surface of the fourth outer leg lower portion 124b, and the upper surface of the second middle leg lower portion 123. In other words, the thickness of the heat dissipation member 800 can be reduced to save on material costs, and the heat dissipation effect can be improved by minimizing the thermal conductivity resistance of the heat dissipation member 800 itself.

[0201] In yet another embodiment, a bobbin on which the heat dissipation member 800 and the coil portion 200 can be arranged may be placed between the upper core 110 and the lower core 120.

[0202] The heat dissipation member 800 may be formed from an insulator having an insulating property of 500 v / mm or more and a thermal conductivity of 3.0 W / mK or more. For example, the heat dissipation member 800 may be formed from any one of the following: alumina (Al2O3), boron nitride (BN), silicon (Si), or mixtures thereof.

[0203] The heat dissipation member 800 can minimize the temperature rise of the transformer 3 by releasing the heat generated in the core portion 100 and the coil portion 200, thereby achieving thermal equilibrium for the transformer 3.

[0204] Although the invention has been described above based on examples, these are merely illustrative and do not limit the invention. Those with ordinary skill in the art to which the invention pertains will understand that various modifications and applications not exemplified above are possible, as long as they do not deviate from the essential characteristics of these examples. For example, each component specifically shown in the examples can be modified and implemented. Any differences related to such modifications and applications should be interpreted as falling within the scope of the invention as defined in the appended claims. [Industrial applicability]

[0205] The transformer and circuit board containing the same according to the present invention can be used in power supply devices for electronic products.

Claims

1. Lower core and a core section including the upper core, A bobbin portion is disposed within the core portion, The coil portion includes a primary coil and a secondary coil, at least a portion of which are disposed on the bobbin portion and which are spaced apart from each other in a second direction that intersects a first direction from the upper core to the lower core, The lower core is A closed region superimposed with the upper core in the first direction, It includes an open region extending from the closed region in a third direction intersecting the first and second directions, and separated from the upper core, The closed region includes a pair of first lower outer feet and a first lower metafoot positioned between the pair of first lower outer feet, The open region includes a pair of second lower outer feet and a second lower midfoot positioned between the pair of second lower outer feet. The first lower metatarsal and the second lower metatarsal are positioned apart from each other. At least a portion of the primary coil and the secondary coil is positioned between the first lower middle leg and the second lower middle leg. A transformer in which the primary coil, the secondary coil, and the first lower midfoot are all superimposed on each other in the second direction, at least in part.

2. The transformer according to claim 1, wherein the primary coil, the secondary coil, the first lower midfoot, and the second lower midfoot are all superimposed on each other in the third direction, at least in part.

3. The transformer according to claim 2, wherein the other of the primary coil and the secondary coil are arranged in the closed region and the open region so as to surround the first lower midfoot and the second lower midfoot.

4. The transformer according to claim 3, wherein the secondary coil is positioned more adjacent to the first lower middle leg than the primary coil.

5. The transformer according to claim 4, wherein the length of the primary coil in the third direction is greater than the length of the secondary coil in the third direction.

6. The transformer according to claim 1, wherein the area of ​​the closed region in the first direction is larger than the area of ​​the open region in the first direction.

7. The transformer according to claim 6, wherein the distance between the first lower midfoot and the second lower midfoot is greater than the length of the second lower midfoot in the third direction.

8. The transformer according to claim 7, wherein the distance between the first lower midfoot and the second lower midfoot is 3 mm to 20 mm.

9. The upper core includes a first upper midfoot positioned on the first lower midfoot, The transformer according to claim 1, wherein the terminal surface of the first lower midfoot toward the second lower midfoot and the terminal surface of the first upper midfoot toward the second lower midfoot are arranged on the same virtual plane.

10. The upper core includes a first upper outer foot, which is positioned on the pair of first lower outer feet, The transformer according to claim 9, wherein the respective end faces of the first lower outer foot toward the second lower outer foot and the respective end faces of the first upper outer foot toward the second lower outer foot are arranged on the same virtual plane.

11. The transformer according to claim 9, wherein a gap is formed between the first lower midfoot and the first upper midfoot.

12. The transformer according to claim 11, wherein the number of turns of the primary coil is greater than the number of turns of the secondary coil.

13. A circuit board comprising a transformer according to any one of claims 1 to 12.

14. The circuit board according to claim 13, wherein the transformer has a leakage inductance of 15 to 20 μH at a frequency of 160 to 300 kHz.

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