Transformer and circuit board including 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 technology]

[0002] Transformers are used, for example, in power supply devices for display devices. As display devices become increasingly larger and thinner, power supply devices are required to be thinner as well as have high power density and high efficiency characteristics.

[0003] To meet the demand for high density and high efficiency, high frequency power supplies (e.g., LLC resonant converters) have been proposed as power supplies for driving LED backlights, which must have a particularly wide voltage gain, and flat transformers have already been developed and are in use.

[0004] For example, to obtain the desired resonance characteristics in an LLC resonant converter, a flat transformer can increase the leakage magnetic flux by designing the core shape and ensure the desired leakage inductance without having to insert a separate leakage layer or I-type core between the primary and secondary coils.

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

[0006] In particular, for high frequency driving of 160 to 300 kHz, it is necessary to adjust the leakage inductance to be lower than the existing one, and the conventional EE-type core shape has a high leakage inductance, making it unsuitable for high frequency driving.

[0007] In order to realize a lower and more precise leakage inductance than before, it is necessary to change the conventional core structure. Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to solve at least one of the problems of the prior art described above.

[0009] In particular, the present invention aims to provide a transformer that can precisely implement leakage inductance and reduce it compared to the case where a conventional EE-type core is used.

[0010] Another object of the present invention is to provide a transformer that can achieve thermal balance by disposing a heat dissipation member in the application structure of the present invention to dissipate heat generated in the core and coil parts, thereby minimizing the temperature rise of the transformer. [Means for solving the problem]

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

[0012] In at least one embodiment of the present invention, a first middle leg and a pair of first outer legs are arranged in the closed region of the core, a second middle leg and a pair of second outer legs are arranged in the open region, and the first coil is wound to surround the first middle leg and the second middle leg.

[0013] In at least one embodiment of the present invention, the second middle foot is spaced a predetermined distance from the first middle foot, and the pair of second outer feet is spaced a predetermined distance from the pair of first outer feet.

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

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

[0016] In at least one embodiment of the present invention, the first middle foot upper part and the pair of first outer foot upper parts, which face the second middle foot and the pair of second outer feet, respectively, and the first middle foot lower part and the pair of first outer foot lower parts, respectively, are located on the same imaginary plane.

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

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

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

[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] 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 area is smaller than the planar area of ​​the closed area.

[0023] An embodiment of a circuit board according to the present invention includes at least one of the above-described embodiments of the transformer.

[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] The circuit board can also be mounted with other electronic components, and the surface can have plated lines formed in a predetermined pattern for the electrical circuit configuration of the components. The circuit board can, for example, configure an LLC resonant converter and be included in a power supply device for a display.

[0026] At least one embodiment of a transformer according to the present invention includes a core section including a lower core section having a first lower midfoot part and a second lower midfoot part spaced a first separation distance from the first lower midfoot part, and an upper core section arranged on the lower core section and having an upper midfoot part overlapping with the first lower midfoot part; a first coil surrounding the first lower midfoot part and the upper midfoot part and arranged in a space of the first separation distance; and a second coil arranged outside the first coil and surrounding the first lower midfoot part, the upper midfoot part, and the second lower midfoot part, wherein at least a portion of the first coil and the second coil are arranged within the core section; the lower core section includes a closed region overlapping with the upper core part in a first direction from the lower core section to the upper core section, and an open region extending from the closed region in a second direction perpendicular to the first direction and exposed from the upper core section; the second lower midfoot part is arranged at a first thickness along the second direction, and the first coil and the second coil are spaced apart by a first separation distance that is equal to or greater than the first thickness.

[0027] The upper core portion may be disposed in the closed region and include a first outer foot upper portion and a second outer foot upper portion, each spaced a predetermined distance from the upper midfoot portion; the lower core portion may be disposed in the closed region and include a first outer foot lower portion and a second outer foot lower portion, each spaced a predetermined distance from the first lower midfoot portion; and may be disposed in the open region and include the second lower midfoot portion and a third outer foot lower portion and a fourth outer foot lower portion, each spaced a predetermined distance from the second lower midfoot portion.

[0028] In addition, in at least one embodiment of the present invention, the midfoot upper, the first outer foot upper, and the second outer foot upper formed along the second direction may be arranged at a first length in the closed area, and the first midfoot lower, the first outer foot lower, and the second outer foot lower formed at the first length along the second direction may overlap the midfoot upper, the first outer foot upper, and the second outer foot upper, respectively.

[0029] In at least one embodiment of the present invention, the second midfoot lower part, the third outer foot lower part, and the fourth outer foot lower part formed with the first thickness may be arranged in the open area, and the second midfoot lower part, the third outer foot lower part, and the fourth outer foot lower part may be arranged separated from the first midfoot lower part, the first outer foot lower part, and the second outer foot lower part by the first separation distance E1, respectively.

[0030] In at least one embodiment of the present invention, the core upper portion may include a first groove portion disposed between the midfoot upper portion and the first outer foot upper portion and relatively recessed by the midfoot upper portion and the first outer foot upper portion, and a second groove portion disposed between the midfoot upper portion and the second outer foot upper portion and relatively recessed by the midfoot upper portion and the second outer foot upper portion.

[0031] The core lower portion includes a fourth groove portion disposed between the first midfoot lower portion and the first lateral foot lower portion and relatively recessed by the first midfoot lower portion and the first lateral foot lower portion, and a fifth groove portion disposed between the first midfoot lower portion and the second lateral foot lower portion and relatively recessed by the first midfoot lower portion and the second lateral foot lower portion, and the fourth groove portion and the fifth groove portion disposed in the closed region may be disposed 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 area may include a third groove portion disposed between the second middle foot lower part and the first middle foot lower part, between the third outer foot lower part and the first outer foot lower part, and between the fourth outer foot lower part and the second outer foot lower part, which are spaced apart by the first separation distance, and which is relatively recessed by the second middle foot lower part, the first middle foot lower part, the third outer foot lower part, the first outer foot lower part, the fourth outer foot lower part, and the second outer foot lower part.

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

[0034] Here, the first-1 horizontal coil portion and the second-1 horizontal coil portion may be spaced apart by the first separation distance.

[0035] The first vertical coil portion and the second vertical coil portion may be spaced apart by a second distance that is smaller than the first 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 greater than or equal to 2 mm 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 part formed along a third direction perpendicular to the second direction may be the same as the width of the second midfoot part formed along the third direction perpendicular to the second direction.

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

[0042] Here, the first midfoot lower part formed along a third direction perpendicular to the second direction may be arranged with a first width, and the second midfoot lower part formed along the third direction may be arranged with a second width, and the second width may be arranged with a width that is 10% to 30% larger than the first width.

[0043] In at least one embodiment of the present invention, a heat dissipation member may be further disposed in the open area, covering a portion of the first coil and the second coil and a portion of a lower portion of the core.

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

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

[0046] Here, the heat dissipation member may be made of any one of alumina (Al2O3)-based, boron nitride (BN)-based, silicon (Si)-based, and a mixture thereof.

[0047] In at least one embodiment of the present invention, the heat dissipation member may have an insulating property 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, a magnetic component suitable for high frequency driving can be obtained.

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

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

[0051] Furthermore, by disposing a heat dissipation member in the application structure of the present invention, heat generated in the core and coil parts can be dissipated, minimizing the temperature rise of the transformer, thereby achieving thermal balance of the transformer. [Brief explanation of the drawings]

[0052] [Figure 1] 1 is a diagram showing a transformer as an embodiment of a magnetic component according to the present invention (illustration of a primary coil and a secondary coil is omitted in FIG. 1).

[0053] [Figure 2]2 is an exploded perspective view of the transformer of FIG. 1 (the primary coil and secondary coil are shown together in FIG. 2).

[0054] [Figure 3] FIG. 3 is a diagram illustrating the core shown in FIG. 2.

[0055] [Figure 4] 4A and 4B are diagrams showing the lower part of the core of FIG. 3 {(a) shows the planar shape of the lower part of the core, and (b) shows the front shape of the lower part of the core}.

[0056] [Figure 5] 4A and 4B are diagrams showing the upper part of the core of FIG. 3 {(a) shows the top of the core of FIG. 3 in a plan view, and (b) shows the right side view of the top of the core}.

[0057] [Figure 6] FIG. 3 is a diagram showing a first bobbin part shown in FIG. 2. [Figure 7] FIG. 3 is a diagram showing a first bobbin part shown in FIG. 2.

[0058] [Figure 8] 7A and 7B are a front view and a right side view of the first bobbin part of FIG. 6.

[0059] [Figure 9] FIG. 3 is a view showing a second bobbin part shown in FIG. 2. [Figure 10] FIG. 3 is a view showing a second bobbin part shown in FIG. 2.

[0060] [Figure 11] 10 is a diagram showing a state in which the first bobbin part 40 and the second bobbin part 30 are joined together. FIG.

[0061] [Figure 12] 1A to 1C are diagrams illustrating a first embodiment of a method for winding a secondary coil in the present invention.

[0062] [Figure 13]FIG. 10 is a diagram showing a second embodiment of a method for winding a secondary coil in the present invention.

[0063] [Figure 14] FIG. 10 illustrates the relationship between leakage inductance and gap for a core according to an embodiment of the present invention.

[0064] [Figure 15] FIG. 10 is a perspective view of a transformer, which is one of magnetic components according to another embodiment of the present invention.

[0065] [Figure 16] FIG. 10 is a plan view of a transformer according to another embodiment of the present invention.

[0066] [Figure 17] FIG. 10 is a side view of a transformer according to another embodiment of the present invention.

[0067] [Figure 18] 10 is a perspective view of a core unit from which a coil unit is removed according to another embodiment of the present invention; FIG.

[0068] [Figure 19] 10A and 10B are plan views of the upper and lower cores of a transformer according to another embodiment of the present invention.

[0069] [Figure 20] 1A is a graph showing the measured leakage inductance of a conventional transformer having no open area, and FIG. 1B is a graph showing the measured leakage inductance of a transformer having an open area according to another embodiment of the present invention.

[0070] [Figure 21] 10 is a graph comparing current density with inductance of a transformer according to another embodiment of the present invention and a conventional transformer.

[0071] [Figure 22]FIG. 10 is a plan view of a transformer according to yet another embodiment of the present invention.

[0072] [Figure 23] FIG. 10 is a plan view of a transformer according to yet another embodiment of the present invention.

[0073] [Figure 24] FIG. 10 is a side view of a transformer according to yet another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0074] Although the present invention can be modified in various ways and can have various embodiments, specific embodiments will be described below with reference to the drawings. However, it should be understood that the present invention is not intended to be limited to the specific embodiments, and that all modifications, equivalents, and alternatives within the spirit and technical scope of the present invention are included.

[0075] The suffixes "module" and "section" used herein are used merely for the purpose of nominal division between components and should not be construed as an assumption that they are physicochemically separate or separated or capable of being so separated or separated.

[0076] Terms including ordinal numbers such as "first" and "second" may be used to describe various components, but the components are not limited to these terms. These terms are used only to distinguish one component from another.

[0077] The term "and / or" is used to include all combinations of the items it refers to. For example, "A and / or B" means "A," "B," and "A and B."

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

[0079] In the description of the embodiments, a description that a layer (film), region, pattern, or structure is formed "on" or "under" a substrate, layer (film), region, pad, or pattern includes both directly and via other layers. Furthermore, unless otherwise specified in the specification or by the attributes of each component or between them, the terms "on" and "under" are used primarily for convenience to indicate the relative positional relationship between components, based on the state shown in the drawings, and should not be construed as limiting the actual positions of the components. For example, "on top of B" merely indicates that B is shown on top of A in the drawings, unless otherwise specified or unless A must be located on top of B due to the attributes of A and B. In an actual product, B may be located below A, or B and A may be located side by side.

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

[0081] The terms used in this application are merely used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as "comprise" or "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and should be understood not to preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0082] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly 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 a meaning consistent with the meaning they have in the context of the relevant art, and should not be interpreted as idealized or overly formal unless expressly defined in this application.

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

[0084] First, FIG. 1 shows a transformer as an embodiment of a magnetic component according to the present invention (illustration of a primary coil 50 and a secondary coil 60 is omitted from the drawing of FIG. 1). 2 is an exploded perspective view of the transformer of FIG. 1, FIG. 3 is a diagram showing the core shown in FIG. 2, FIG. 4 is a diagram showing the lower core part 20 of the core of FIG. 3 {(a) shows the planar shape of the lower core part 20, and (b) shows the front shape of the lower core part 20}, FIG. 5 is a diagram showing the upper core part 10 of the core of FIG. 3 {(a) shows the planar shape of the upper core part 10 of the core of FIG. 3 turned upside down, and (b) shows the right side shape of the upper core part 10}, FIGS. 6 and 7 are diagrams showing the first bobbin part 40 shown in FIG. 2, FIG. 8 is a front view and a right side view of the first bobbin part 40 of FIG. 6, FIGS. 9 and 10 are diagrams showing the second bobbin part 30 shown in FIG. 2, and FIG. 11 is a diagram showing the first bobbin part 40 and the second bobbin part 30 joined together.

[0085] The core shown in FIGS. 1 and 2 will be described in detail with reference to FIGS.

[0086] The core according to this embodiment includes an upper core 10 and a lower core 20, and the upper core 10 is overlapped with the lower core 20 in a first direction from bottom to top and is disposed on the lower core 20 to form a single core.

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

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

[0089] In the closed area Ac, a first midfoot lower part 21 and a pair of first outer foot lower parts 22a, 22b are formed, with the first midfoot lower part 21 sandwiched therebetween.

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

[0091] The first middle foot lower part 21 has grooves r1 and r2 formed on both sides thereof, and is therefore separated from the first outer foot lower parts 22a and 22b by a distance equal to the width of the grooves.

[0092] In the open area Ao, a second middle leg 23 and a pair of second outer legs 24a, 24b are formed, with the second middle leg 23 sandwiched therebetween.

[0093] As shown in FIG. 4, the outer corner of the second middle foot 23 has a rounded shape, and all of the corners of the second outer feet 24a and 24b have angular shapes (round shapes with a radius much smaller than the round shape of the outer corner of the second middle foot), but this is not limited to this.

[0094] The second middle leg 23 also has grooves r1 and r2 formed on both sides thereof, so that it is spaced apart from the second outer legs 24a and 24b at a predetermined interval.

[0095] In the open area Ao, grooves r3 are formed between the first midfoot lower part 21 and the second midfoot 23 and between the first outer foot lower parts 22a, 22b and the second outer foot 24a, 24b, and the grooves r3 separate the first midfoot lower part 21 and the second midfoot 23 by a distance equal to the width of the grooves.

[0096] The core upper 10 is arranged in the closed area Ac of the core lower 20, with a first midfoot upper 11 formed in the center, and a pair of first outer foot uppers 12a, 12b arranged with the first midfoot upper 11 sandwiched between them.

[0097] The first midfoot upper 11 also has grooves r4 and r5 formed on both sides, so that it is spaced apart from the first outer foot uppers 12a and 12b by a distance equal to the width of the grooves. The grooves r4 and r5 of the core upper 10 and the grooves r1 and r2 of the core lower 10 have the same width w.

[0098] In addition, each of the first midfoot upper parts 11 has a rounded shape at its corners, and each of the first outer foot upper parts 12a, 12b has an angular shape at its corners (a rounded shape with a radius much smaller than the rounded shape of the first midfoot), but is not limited to this.

[0099] In the core upper part 10 and the core lower part 20, the closed area Ac has a structure symmetrical to each other when assembled.

[0100] The core upper 10 in Fig. 5 is in the shape (Fig. 5(a)) of the core upper 10 shown in Fig. 3 in which it has been turned over and its right side shape (Fig. 5(b)) is shown. In the assembled state shown in Fig. 3, the first midfoot upper 11 of the core upper 10 is placed on the first midfoot lower 21, and the upper first outer foot upper 12b and lower first outer foot upper 12a in Fig. 5 are placed on the lower first outer foot lower 22b and upper first outer foot lower 22a in Fig. 4, respectively.

[0101] Preferably, the core upper 10 is disposed above the core lower 20 so as to have a predetermined gap therebetween. For this reason, a gap may be formed between the first midfoot upper and first midfoot lower parts 11, 21 and / or between the first outer foot upper and first outer foot upper parts 12a, 12b, 22a, 22b.

[0102] By placing the core upper part 10 on the core lower part 20, the first midfoot upper part 11 and the first midfoot lower part 21 form the first midfoot, and the first outer foot upper parts 12a, 12b and the first outer foot lower parts 22a, 22b form the first outer foot.

[0103] As shown in Figures 3 to 5, when the core upper part 10 is positioned on the core lower part 20, the end faces of the first midfoot upper part 11 and the pair of first outer foot upper parts 12a, 12b, and the first midfoot lower part 21 and the pair of first outer foot lower parts 22a, 22b, which face the second midfoot 23 and the pair of second outer feet 24a, 24b, respectively, can be positioned on the same imaginary plane P.

[0104] In this core structure, the primary coil 50 and secondary coil 60 are disposed inside the core, the primary coil 50 being wound so as to surround the first center legs 11, 21 and the second center leg 23 and being disposed in the closed area Ac and the open area Ao of the core, and the secondary coil 60 being wound so as to surround only the first center legs 11, 21 and being disposed in the closed area Ac. Here, a portion of the secondary coil 60 may be disposed in the open area Ao beyond the closed area Ac. 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] The primary coil 50 and secondary coil 60 are linked in the closed area Ac, and the two coils 50, 60 are not linked in the open area Ao. In the closed area Ac, where the two coils 50, 60 are linked, voltage conversion is achieved, and in the open area Ao, which is a non-linkage area, the leakage inductance generated in the closed area Ac is canceled out through leakage magnetic flux, thereby inducing a desired amount of leakage inductance. By adjusting the overall leakage inductance low by canceling out the relatively large leakage inductance generated in the closed area Ac, as in conventional EE-type cores, a lower leakage inductance than conventional cores can be achieved.

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

[0108] Meanwhile, in this embodiment, the bobbin includes a first bobbin part 40 and a second bobbin part 30, and as shown in FIG. 11, the first bobbin part 40 is inserted under the second bobbin part 30 for assembly.

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

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

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

[0112] An upper rim 45 is formed between the upper plate 41 and the mid plate 42 to surround the upper part of the first metatarsal through-hole 44, and a lower rim 46 is formed between the mid plate 42 and the lower plate 43 to surround the lower part of the first metatarsal through-hole 44 and the second metatarsal accommodating groove 47.

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

[0114] A pair of core guides 41a, 41b protruding upward are provided on the top plate 41 of the first bobbin part 40. When the first bobbin part 40 is inserted into the second bobbin part 30, the pair of core guides 41a, 41b protrude higher above the top surface of the second bobbin part 30, and the core upper part 10 is positioned between the pair of core guides 41a, 41b. The pair of core guides 41a, 41b makes it easy to position the core relative to the bobbin (or coil).

[0115] The second bobbin portion 30 includes a primary terminal portion 32 and a secondary terminal portion 33 on either side thereof, and a body portion 31 between the terminal portions 32 and 33 .

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

[0117] The secondary terminal portion 33 has a plurality of second coil wire grooves 33a arranged alternately in a row, and a second wiring protrusion 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 for the secondary coil 60. Accordingly, the secondary terminal portion 33 in this embodiment includes a total of eight second coil wire grooves 33a. Here, each secondary coil 60 is pulled out through the second coil wire grooves 33a and can contact a separate terminal pin (not shown).

[0119] The second bobbin part 30 has a middle plate accommodating groove 36 formed in its lower part as a non-through groove for accommodating the middle plate 42 (or the lower plate 43) of the first bobbin part 40. The second bobbin part 30 also has an upper plate accommodating through groove 34 formed in its lower part as a through groove for accommodating the upper plate 41 of the first bobbin part 40.

[0120] Here, a plurality of fixing protrusions 36a are formed on the peripheral wall of the middle plate accommodating groove 36 to prevent the middle plate 42 (or lower plate 43) of the first bobbin part 40 from falling out downward while accommodated.

[0121] A first terminal wire passage 42a is formed in the middle plate 42 of the first bobbin part 40, through which the terminal wire of the primary coil 50 housed in the primary coil housing portion passes, and a second terminal wire passage 35 corresponding to the first terminal wire passage 42a is formed in the second bobbin part 30, so that the terminal wire of the primary coil 50 passes through the primary terminal portion 32. Protrusions 42b and 42c for fixing the coil wire of the primary coil 50 are formed on both sides of the first terminal wire passage 42a of the middle plate 42 of the first bobbin part 40.

[0122] In this embodiment, the peripheral wall 34a of the upper plate receiving through-groove 34 is disposed to surround the secondary coil receiving space. The secondary coil 60 is received in the secondary coil receiving space formed between the upper rim 45 of the first bobbin part 40 and the peripheral wall 34a of the upper plate receiving through-groove 34.

[0123] Here, as shown in FIG. 9, the peripheral wall 34a of the upper plate receiving through-groove 34 on the secondary terminal portion 33 side has a low or almost no wall height, providing a passage for each coil wire of the secondary coil 60 toward the secondary terminal portion 33, and an inclined surface 37 is formed so that the width gradually increases and the height gradually increases toward the secondary terminal portion 33, thereby acting as a guide and support for the arrangement of the terminal wires of the secondary coil 60, thereby increasing the degree of freedom in the arrangement of the terminal wires and making wiring work easier.

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

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

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

[0127] The diagram shown in the upper part of Figure 12 shows the wiring of the secondary coil 60 according to the first embodiment on the second bobbin part 30, and the diagram shown in the lower part shows a wiring diagram in which each coil wire constituting the secondary coil 60 is connected to a second terminal pin.

[0128] TIFF2024510325000002.tif17170

[0129] TIFF2024510325000003.tif10170

[0130] TIFF2024510325000004.tif25170

[0131] The winding method of the secondary coil 60 in this embodiment makes the entire length of the secondary output winding the same, which has the effect of improving current imbalance between the coil wires of the secondary coil 60 compared to the comparative example. In addition, the wiring and structure of the secondary coil 60 reduces resistance to the applied current, thereby improving the efficiency of the transformer and reducing heat generation due to resistance, thereby suppressing heat generation in the transformer.

[0132] Meanwhile, Figure 14 shows the relationship between leakage inductance and the spacing (r3 spacing) between the first middle leg lower part 21 and the second middle leg 23 for a core according to an embodiment of the present invention (represented as "open core" in Figure 14(b)). As shown in Figure 14, the leakage inductance of the core according to an embodiment of the present invention gradually decreases at a large rate as the spacing increases, and it is possible to achieve a lower leakage inductance than the conventional EE-type core.

[0133] Therefore, the leakage inductance can be adjusted more precisely by adjusting the spacing between the first and second center legs, and it is possible to adjust the leakage inductance to 15 to 20 μH when driving at high frequencies of 160 to 300 kHz.

[0134] Figure 15 is an oblique 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 an oblique view of a core part from which the coil part has been removed according to another embodiment of the present invention; and Figure 19 is a plan view of the upper and lower core parts of a transformer according to one embodiment.

[0135] 15 to 19, a transformer 1 according to another embodiment of the present invention includes a core portion 100 and a coil portion 200. As shown in FIG.

[0136] The core section 100 includes an upper core section 110 and a lower core section 120, and the upper core section 110 is disposed on the lower core section 120 so as to overlap with the lower core section 120 in a first direction (z-axis direction) from the bottom to the top.

[0137] Specifically, referring to Figures 18 and 19(b), the core upper 110 has a midfoot upper 111 that protrudes from one surface of the first base and is arranged in the central region of the first base, and first and second outer foot uppers 112a, 112b that are arranged on both sides of the midfoot upper 111, spaced 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 overall width w. Since the second base of the core lower part 120 described below is disposed to overlap the core upper part 110, the overall width of the second base may also be formed to be the same overall width w. Since the midfoot upper part 111 and the first and second outer foot upper parts 112a, 112b protrude from the first base, fourth and fifth groove parts r4, r5 may be disposed in the core upper part 110 so as to be relatively recessed by the midfoot upper part 111 and the first and second outer foot upper parts 112a, 112b.

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

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

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

[0142] The core lower part 120 may include first and second outer foot lower parts 122a, 122b spaced apart at a predetermined interval on either side of the first midfoot lower part 121, and third and fourth outer foot lower parts 124a, 124b spaced apart at a predetermined interval on either side of the second midfoot lower part 123. The distance between the first midfoot lower part 121 and the first outer foot lower part 122a may be a first width W1, and the distance between the first midfoot lower part 121 and the second outer foot lower part 122b may be a second width W2. In consideration of ease of molding the core lower part 120, the distance between the second midfoot lower part 123 and the third outer foot lower part 124a may also be the first width W1. The distance between the second midfoot lower part 123 and the fourth outer foot lower part 124b may also be the second width W2.

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

[0144] The first groove portion r1 may be disposed between the first midfoot lower part 121 and the first outer foot lower part 122a and between the second midfoot lower part 123 and the third outer foot lower part 124a. The second groove portion r2 may be disposed between the first midfoot lower part 121 and the second outer foot upper part 112b and between the second midfoot lower part 123 and the fourth outer foot lower part 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 thereto, and may be formed to have different widths.

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

[0147] Meanwhile, the second base of the lower core portion 120 may be formed with a third length K3 extending in the second direction (Y-axis direction). Here, the region of the third length K3 may be the first length K1 plus the second length K2. When the lower core portion 120 is coupled to the upper core portion 110, the region of the first length K1 may be a region where the lower core portion 120 and the upper core portion 110 overlap, and the region of the second length K2 may be a region where the lower core portion 120 is exposed from the upper core portion 110.

[0148] The region of second length K2 may include a first thickness G1 of 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). Also, the region of second length K2 may include a second thickness G2 of third and fourth outer foot lower parts 124a, 124b and a second separation distance E2, which is the separation distance between first and second outer foot lower parts 122a, 122b and third and fourth outer foot lower parts 124a, 124b.

[0149] In this embodiment, the core lower portion 120 is formed with ease of molding in mind, and therefore, the first thickness G1 and the second thickness G2 are the same, and the first separation distance E1 and the second separation distance E2 are illustrated and described. Here, the first thickness G1 and the second thickness G2 are described as being the same, but the present invention is not limited thereto, and the first thickness G1 and the second thickness G2 may be different from each other. Furthermore, the first separation distance E1 and the second separation distance E2 are described as being the same, but the present invention is not limited thereto, and the first separation distance E1 and the second separation distance E2 may be different from each other.

[0150] The first midfoot lower part 121, the first outer foot lower part 122a and the second outer foot lower part 122b may be formed to have the same length as the first length K1 so as to correspond to the midfoot upper part 111, the first outer foot upper part 112a and the second outer foot upper part 112b, respectively, but are not limited to this.

[0151] The second midfoot lower part 123, the third outer foot lower part 124a, and the fourth outer foot lower part 124b may be disposed in the region of the second length K2. The region of the second length K2 may also be provided with a first separation distance E1 separating the second midfoot lower part 123 and the first midfoot lower part 121, a second separation distance E2 separating the third outer foot lower part 124a and the first outer foot lower part 122a, and a third separation distance E3 separating the second outer foot upper part 112b and the fourth outer foot lower part 124b. A third groove r3, which is recessed relatively by the second base and the midfoot and outer foot protruding from the second base, may be disposed at the first separation distance E1 and the second separation distance E2.

[0152] In this way, the core portion 100 is arranged so that the length of the upper core portion 110 and the length of the lower core portion 120 are different, and therefore includes a closed area Ac where the upper core portion 110 and the lower core portion 120 overlap each other, and an open area Ao where the lower core portion 120 is exposed by the upper core portion 110.

[0153] In this embodiment, the planar area of ​​the open area Ao may be smaller than the planar area of ​​the closed area Ac, i.e., the area of ​​the second length K2 may be smaller than the area of ​​the first length K1.

[0154] For example, the closed area Ac is an area that is closed by overlapping and covered by the upper core 10 in a first direction (z-axis direction) from the lower core 120 toward the upper core 110, and the open area Ao is an area that extends from the closed area 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 an area exposed outside the closed area Ac.

[0155] The closed region Ac is disposed in a region of the first length K1, and may be disposed so that the first midfoot lower part 121 and the midfoot upper part 111 overlap, the first outer foot upper part 112a and the first outer foot lower part 122a overlap, and the second outer foot upper part 112b and the second outer foot lower part 122b overlap. Furthermore, the first and second groove parts r1 and r2, which are relatively recessed, and the fourth and fifth groove parts r4 and r5 overlap.

[0156] The open area Ao is arranged in an area of ​​the second length K2, in which the second midfoot lower part 123, the third outer foot lower part 124a and the fourth outer foot lower part 124b are arranged, and a third groove r3 may be arranged between the second midfoot lower part 123, the third outer foot lower part 124a and the fourth outer foot lower part 124b and the closed area Ac.

[0157] Furthermore, the regions of the first and second groove portions r1, r2 that do not overlap with the fourth and fifth groove portions r4, r5 may be arranged in the open region Ao. Hereinafter, the regions where the first and second groove portions r1, r2 and the fourth and fifth groove portions r4, r5 overlap will be referred to as the fourth and fifth groove portions r4, r5, and the regions where the first and second groove portions r1, r2 and the fourth and fifth groove portions r4, r5 do not overlap will be referred to as the first and second groove portions r1, r2.

[0158] 15 to 19, the coil portion 200 includes a first coil 210 and a second coil 220 that pass through the inside of the core portion 100. Here, for ease of explanation, the first coil 210 and the second coil 220 will be described taking a square loop shape as an example.

[0159] The first coil 210 may be arranged in a shape that surrounds the overlapping region of the upper midfoot part 111 and the first lower midfoot part 121. Specifically, the first coil 210 includes a first vertical coil part 213 extending along the Y-axis direction and disposed in the fourth and fifth groove parts r4 and r5, a first-1 horizontal coil part 215 extending along the X-axis direction and disposed between the second lower midfoot part 123 and the first lower midfoot part 121, and a first-2 horizontal coil part 218 disposed on the opposite side facing the first-1 horizontal coil part 215.

[0160] The first-1 horizontal coil portion 215 of the first coil 210 may be disposed in a third groove r3 formed in the open region Ao. Therefore, the first-1 horizontal coil portion 215 of the first coil 210 may be disposed in a region of the second length K2 that does not overlap with the upper core portion 110. Therefore, the third groove r3 may be formed with a width that can accommodate the width of the first-1 horizontal coil portion 215 of the first coil 210. For example, the third groove r3 disposed at the first separation distance E1 may be formed with a thickness in the range of 3 mm to 20 mm along the Y-axis direction.

[0161] Here, the third groove r3 is determined in the Y-axis direction by the wire diameter of the secondary coil, which must be at least 3 mm thick to apply a secondary coil suitable for the allowable current. If it exceeds 20 mm, core loss will increase and performance will not be fully achieved.

[0162] The first vertical coil portion 213 of the first coil 210 is disposed in the fourth and fifth groove portions r4 and r5 where the upper core portion 110 and the lower core portion 120 are overlapped, and a portion of the first vertical coil portion 213 may be disposed in a region where the first and second groove portions r1 and r2 and the third groove portion r3 overlap in order to be connected to the 1-1 horizontal coil portion 215. In other words, a portion of the first vertical coil portion 213 may be disposed in the closed region Ac, and another portion may be disposed in the open region Ao.

[0163] The first-second horizontal coil section 218 of the first coil 210 may be disposed outside the closed region Ac, i.e., outside the region of the first length K1. That is, the first vertical coil section 213 may be disposed in the first length region K1, the region of the second length K2, and outside the region of the first length K1. Here, the outside of the region of the first length K1 is an outer region disposed on the opposite side of the region of the first length K1 from the region of the second length K2.

[0164] The second coil 220 may be arranged in a shape surrounding the overlapping region of the upper midfoot part 111 and the first lower midfoot part 121 and the second lower midfoot part 123. Specifically, the second coil 220 includes a second vertical coil part 223 extending in the Y-axis direction and arranged in the fourth and fifth groove parts r4 and r5, a second-first horizontal coil part 225 extending in the X-axis direction and arranged adjacent to the second lower midfoot part 123 and outside the closed region Ac, and a second-second horizontal coil part 228 arranged on the opposite side facing the second-first horizontal coil part 225.

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

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

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

[0168] In other words, a portion of the second vertical coil portion 223 may be disposed in the closed region Ac, another portion may be disposed in the open region Ao, and still another portion may be disposed in a region outside the open region Ao. Thus, the second coil 220 may include a second vertical coil portion 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 portion 213 and the second vertical coil portion 223 may be arranged in the fourth and fifth groove portions r4 and r5 or the first and second groove portions r1 and r2 with the first separation distance D1 described above. Alternatively, they may be arranged with a second separation distance D2 different from the first separation distance D1. The reason why the separation distances between the first vertical coil portion 213 and the second vertical coil portion 223 are different is because there is a limit to increasing the overall width w of the core portion 100 in order to realize a light, thin, short, and compact transformer. Therefore, the second separation distance D2 described above may be smaller than the first separation distance D1.

[0170] The 2-2 horizontal coil portion 228 of the second coil 220 may be disposed outside the closed area Ac, that is, outside the area of ​​the third length K3.

[0171] Meanwhile, 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 thickness of the first coil 210 greater than the thickness of the second coil 220, the number of turns of the first coil 210 may be greater than the number of turns of the second coil 220.

[0172] The first coil 210 and the second coil 220 can be linked in the closed area Ac, and can be unlinked in the open area Ao. Voltage conversion is achieved in the closed area Ac where the first coil 210 and the second coil 220 are linked, and in the open area Ao, which is a non-linkage area, leakage inductance generated in the closed area Ac is offset by leakage magnetic flux, thereby inducing a desired magnitude of leakage inductance.

[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 midfoot portion 111 and the first lower midfoot portion 121, it is possible to induce a desired amount of leakage inductance while maintaining a constant value of self-inductance (Lp).

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

[0175] Figure 20(a) is a graph showing the measured leakage inductance of a conventional transformer without an open area, Figure 20(b) is a graph showing the measured leakage inductance of a transformer with an open area 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] 20(a) and 21, it can be seen that in a transformer in which only a closed area Ac is arranged, as in the case of a conventional EE-type core, a large leakage inductance occurs due to the closed area Ac. It can be seen that a leakage inductance of 3.1 A occurs in the m1 area shown in the graph.

[0177] 20(b) and 21, it can be seen that a lower leakage inductance can be achieved by adjusting the leakage inductance lower through cancellation in the open area Ao. It can be seen that a leakage inductance of 3A occurs in the m1 area shown in the graph.

[0178] When the same current is applied to a conventional transformer and the transformer of this embodiment, the magnetic flux and current density induced in the coil unit 200 can be lower even if a higher current flows because the magnetic flux flows counterbalanced between the first midfoot lower part 121 and the second midfoot lower part 123. This is because the open area Ao can accommodate more magnetic flux density, thereby preventing the core unit 100 from becoming saturated.

[0179] Therefore, it can be seen that the open area Ac serves to store additional energy, thereby increasing the power capacity. In other words, it can be seen that the DC-Bias performance of the transformer according to this embodiment is improved compared to the conventional core.

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

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

[0182] In FIG. 22, the explanation of the midfoot is omitted, and for ease of explanation, the explanation will be given with reference to FIGS. 15 to 21.

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

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

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

[0186] In another embodiment of the transformer 2, the first mid-leg lower part 121 and the second mid-leg lower part 123 are formed with different widths, so that the open area Ao serves to store additional energy and increases the high power capacity, and the open area Ac can additionally accommodate magnetic flux density, preventing saturation of the core part 100.

[0187] Therefore, in the transformer 2 according to another embodiment, the first middle leg lower part 121 and the second middle leg lower part 123 are arranged with different widths, so that a desired amount of leakage inductance can be induced while maintaining a constant self-inductance (Lp). In other words, the DC bias of the transformer can be increased with the same self-inductance (Lp).

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

[0189] 23 and 24, the description of the midfoot is omitted, and for ease of explanation, the description will be made with reference to FIGS. 15 to 22.

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

[0191] The heat dissipation member 800 may be disposed in the open area Ao and in the area of ​​the second length K2. The second middle leg part 123, the third outer leg part 124a, the fourth outer leg part 124b, and the third groove r3 may be disposed in the area of ​​the second length K2. The second vertical coil part 223 and the first vertical coil part 213 may also be disposed in the area where the first and second grooves r1, r2, and the third groove r3 overlap.

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

[0193] Here, the heat dissipation member 800 not only covers the above-mentioned components but is also arranged in direct contact with them, thereby enabling the heat energy generated in the core part 100 and the coil part 200 to be radiated to the outside. In other words, the heat dissipation member 800 can be arranged in direct contact with the coil part 200, the upper core part 110, and the lower core part 120.

[0194] Specifically, the heat dissipation member 800 may be disposed so as to be in direct contact with the upper and side surfaces of the second vertical coil portion 223 and the first vertical coil portion 213. The heat dissipation member 800 may also be disposed so as to be in direct contact with one surface of the lower core portion 120 disposed in the open area Ao.

[0195] Specifically, the heat dissipation member 800 is arranged to be in direct contact with one surface of the second base of the core lower part 120, and may be arranged to be in direct contact with the thickness surface and upper surface of the second middle leg lower part 123, the thickness surface and upper surface of the third outer leg lower part 124a, and the thickness surface and upper surface of the fourth outer leg lower part 124b, which are protruded from one surface of the second base.

[0196] Also, it may be arranged so as to be in direct contact with the side surface of the core upper portion 110 arranged at the boundary surface P between the region of the first length K1 and the region of the second length K2.

[0197] More specifically, the core upper part 110 may be disposed so as to be in direct contact with the thickness surface of the first base, the thickness surface of the midfoot upper part 111, the thickness surface of the first outer foot upper part 112a, and the thickness surface of the second outer foot upper part 112b, where the core upper part 110 is exposed at the boundary surface P. Furthermore, the thickness surfaces of the first midfoot lower part 121, the first outer foot lower part 122a, and the second outer foot upper part 122b, which overlap with the midfoot upper part 111, the first outer foot upper part 112a, and the second outer foot upper part 112b, respectively, are exposed at the boundary surface P, and therefore may be disposed so as to be in direct contact with the heat dissipation member 800.

[0198] Therefore, the heat dissipation member 800, which is arranged in direct contact with the above-mentioned components, is in direct contact not only in the open area Ao but also in some areas of the upper core 110 and the lower core 120 at the boundary surface P, thereby efficiently radiating the thermal energy generated in the closed area Ac to the outside.

[0199] The heat dissipation member 800 may be disposed in the open area Ao and may be disposed 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 a surface facing the one surface of the first base, and the one surface of the first base is a 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 to have a thickness that exposes the upper surface of the third outer leg lower part 124a, the upper surface of the fourth outer leg lower part 124b, and the upper surface of the second middle leg lower part 123. In other words, by forming the heat dissipation member 800 to be thin, material costs can be reduced and the heat conduction resistance of the heat dissipation member 800 itself can be minimized, thereby improving the heat dissipation effect.

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

[0202] The heat dissipation member 800 may be made of 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 made of any one of an alumina (Al2O3)-based material, a boron nitride (BN)-based material, a silicon (Si)-based material, and a mixture thereof.

[0203] The heat dissipation member 800 can minimize the temperature rise of the transformer 3 by dissipating the heat generated in the core unit 100 and the coil unit 200 to achieve thermal equilibrium of the transformer 3 .

[0204] The above description has been given based on the embodiments, but these are merely examples and are not intended to limit the present invention. Those skilled in the art will recognize that various modifications and applications not exemplified above are possible within the scope of the essential characteristics of the present embodiments. For example, each component specifically illustrated in the embodiments can be modified and implemented. Differences related to such modifications and applications should be interpreted as being included within the scope of the present invention as defined in the appended claims. [Industrial Applicability]

[0205] The transformer and the circuit board including the transformer according to the present invention can be used in the power supply device of an electronic product.

Claims

1. Lower Core and a core portion including an upper core; a bobbin portion at least a portion of which is disposed within the core portion; a coil unit including a primary coil and a secondary coil, at least a portion of which is disposed in the bobbin unit and spaced apart from each other in a second direction intersecting a first direction from the upper core to the lower core, The lower core is a closed region overlapping the upper core in the first direction; an open region extending from the closed region in a third direction intersecting the first direction and the second direction and spaced apart from the upper core, The closed region includes a pair of first outer legs and a first lower middle leg disposed between the pair of first outer legs, The open area includes a pair of second lower outer legs and a second lower middle leg disposed between the pair of second lower outer legs, The first lower midfoot and the second lower midfoot are spaced apart from each other, At least a portion of one of the primary coil and the secondary coil is disposed between the first lower middle leg and the second lower middle leg, the primary coil, the secondary coil and the first lower center leg all at least partially overlap each other in the second direction.

2. The transformer according to claim 1 , wherein the primary coil, the secondary coil, the first lower middle leg, and the second lower middle leg are all at least partially overlapped with each other in the third direction.

3. The transformer according to claim 2 , wherein the other of the primary coil and the secondary coil is disposed in the closed region and the open region so as to surround the first lower middle leg and the second lower middle leg.

4. The transformer of claim 3 , wherein the secondary coil is disposed closest to the first lower mid-leg than the primary coil.

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

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

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

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

9. the upper core includes a first upper midfoot disposed on the first lower midfoot, 2. The transformer of claim 1, wherein a terminal surface of the first lower midfoot toward the second lower midfoot and a terminal surface of the first upper midfoot toward the second lower midfoot are disposed on the same imaginary plane.

10. The upper core includes first upper outer legs disposed on the pair of first lower outer legs, 10. The transformer of claim 9, wherein the end surfaces of the first lower outer leg toward the second lower outer leg and the end surfaces of the first upper outer leg toward the second lower outer leg are arranged on the same imaginary plane.

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

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

13. A circuit board comprising the 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 under a frequency of 160 to 300 kHz.

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