KR20230038159A - Transformer and flat panel display device including the same - Google Patents

Abstract

In accordance with one embodiment of the present invention, a transformer includes: a core unit including an upper core and a lower core; a coil unit partially disposed within the core unit; and a bobbin unit disposed between the core unit and the coil unit, wherein the coil unit includes a first coil and a second coil disposed at least partially on a side of the first coil, the bobbin unit includes a first bobbin having a first housing unit formed to house the first coil, and a second bobbin having a second housing unit formed to house the second coil, the first bobbin includes a first extension unit extended from the first housing unit toward the second bobbin, and the second housing unit can be disposed on the first extension unit. Therefore, the present invention is capable of securing leakage inductance by securing an insulation distance between a primary coil and a core.

Description

Transformer and flat panel display device including the same {TRANSFORMER AND FLAT PANEL DISPLAY DEVICE INCLUDING THE SAME}

The present invention relates to a transformer and a flat panel display device including the same.

In general, driving power is required to drive an electronic device, and a power supply device such as a power supply unit (PSU) is essentially employed to supply such driving power to the electronic device.

In particular, since slimness is required along with the enlargement of the display size in display devices such as flat-panel TVs, there is a problem of reducing the thickness while satisfying the increased power consumption of the enlarged display.

Since the transformer occupies a relatively large volume compared to other components in the power supply unit (PSU), in order to slim down, it is common to omit elements occupying a large thickness in the transformer or to adjust the quantity. For example, in a transformer constituting a power supply unit of a recent flat panel display device, a bobbin in which a primary coil and a secondary coil are wound and fixed is omitted, or a plurality of slim transformers having low capacitance are used.

Such a PSU requires a leakage inductance in a specific range (eg, 50uH or more) for designing a resonance tank of a circuit and matching a frequency. By the way, since a general slim transformer adopts a structure in which a primary coil and a secondary coil are stacked vertically, both the primary coil and the secondary coil contribute to the thickness due to the vertical stacking, so there is a limit to the thickness reduction. There is a problem that the leakage inductance is remarkably low (eg, about 3uH). Leakage inductance needs to be secured above a certain level for switching mode operation in the circuit.

Accordingly, there is a demand for a transformer capable of further slimming and securing leakage inductance and a flat panel display device using the same.

A technical problem to be achieved by the present invention is to provide a slim transformer capable of further slimming and securing leakage inductance and a flat panel display device using the same.

In addition, the present invention is to provide a slim transformer with excellent heat dissipation performance and a flat panel display device using the same.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the description below. You will be able to.

A transformer according to an embodiment includes a core portion including an upper core and a lower core; a coil part partially disposed within the core part; and a bobbin part disposed between the core part and the coil part, wherein the coil part includes a first coil and a second coil having at least a part disposed on a side surface of the first coil, wherein the bobbin part comprises: a first bobbin having a first accommodating portion accommodating the first coil; and a second bobbin having a second accommodating portion accommodating the second coil, wherein the first bobbin includes a first extension portion extending from the first accommodating portion toward the second bobbin, A portion may be disposed on the first extension portion.

For example, the shortest distance between the first coils from the lower surface of the lower core may be different from the shortest distance between the second coils from the lower surface of the lower core.

For example, a first space formed to accommodate a portion of the bobbin portion between the first outer foot portion and the midfoot portion; and a second space formed to accommodate the other part of the bobbin part between the second outer foot part and the mid foot part.

For example, at least a portion of the first coil and the second coil may overlap in a first direction from the first outer foot portion to the second outer leg portion.

For example, the shortest distance between the first coil and the second coil is 0.1 times to 0.3 times the shortest distance between adjacent one of the first outer foot part and the second outer foot part at the outermost part of the first coil. can

For example, compared to the first distance, which is the shortest distance between the first coil and the second coil outside the first space and the second space, the first coil and the second coil in the first space or the second space. The ratio of the second distance, which is the shortest distance between the second coils, may be 1 to 1.3.

For example, the shortest distance between the first coils from the lower surface of the lower core may be 0.3 to 0.7 times the shortest distance between the second coils and the lower surface of the lower core.

For example, the transformer may further include an insulating part disposed between the first outer foot part and the bobbin part in the first space and between the second outer foot part and the bobbin part in the second space. .

For example, the first bobbin may further include a coil lead-out portion disposed on an upper surface thereof, and the second bobbin may include a through hole through which the coil draw-out portion passes to expose the coil draw-out portion.

For example, the first bobbin may include a first top portion; a first bottom portion disposed under the top portion; and a first middle part disposed between the top part and the bottom part, and the first extension part may be disposed in the bottom part.

For example, the second bobbin may include a second top portion; a second bottom portion disposed below the top portion; and a second middle portion disposed between the second top portion and the second bottom portion, wherein at least a portion of the first bobbin is formed in a recess defined by a lower surface of the second top portion and an inner surface of the second middle portion. can be accepted

For example, the first extension part may face a lower surface of the second bottom part.

In addition, the transformer according to an embodiment includes a core portion including an upper core and a lower core; a coil part partially disposed within the core part; and a bobbin part disposed between the core part and the coil part, wherein the coil part includes a first coil and a second coil having at least a part disposed on a side surface of the first coil, An outer foot portion, a second outer foot portion, and a midfoot portion disposed between the first outer foot portion and the second outer foot portion, wherein the shortest distance between the first coil and the second coil is the outermost part of the first coil. It may be 0.1 to 0.3 times the shortest distance between adjacent one of the first outer foot and the second outer foot.

For example, the bobbin unit may include a first bobbin having a first accommodating unit accommodating the first coil; and a second bobbin having a second accommodating portion accommodating the second coil, wherein the first bobbin includes a first extension portion extending from the first accommodating portion toward the second bobbin, A portion may be disposed on the first extension portion.

For example, the shortest distance between the first coils from the lower surface of the lower core may be different from the shortest distance between the second coils from the lower surface of the lower core.

For example, the shortest distance between the first coils and the lower surface of the lower core may be smaller than the shortest distance between the second coils and the lower surface of the lower core.

For example, the second bobbin may include a second extension portion extending from the second accommodating portion toward the first bobbin, and the first accommodating portion may be disposed below the second extension portion.

For example, a part of the second accommodating part may be disposed between the first coil and the second coil.

For example, the core part may include a first space formed to accommodate a part of the bobbin part between the first outer foot part and the middle foot part; and a second space formed to accommodate the other part of the bobbin part between the second outer foot part and the mid foot part.

For example, at least a portion of the first coil and the second coil may overlap in a first direction from the first outer foot portion to the second outer leg portion.

For example, compared to the first distance, which is the shortest distance between the first coil and the second coil outside the first space and the second space, the first coil and the second coil in the first space or the second space. The ratio of the second distance, which is the shortest distance between the second coils, may be 1 to 1.3.

For example, the shortest distance between the first coils and the lower surface of the lower core may be 0.3 to 0.7 times the shortest distance between the second coils and the lower surface of the lower core.

For example, an insulating part disposed between the first outer foot part and the bobbin part in the first space and between the second outer foot part and the bobbin part in the second space may be further included.

For example, the first bobbin may further include a coil lead-out portion disposed on an upper surface thereof, and the second bobbin may include a through hole through which the coil draw-out portion passes to expose the coil draw-out portion.

For example, the first bobbin may include a first top portion; a first bottom portion disposed below the top portion; and a first middle part disposed between the top part and the bottom part, and the first extension part may be disposed in the bottom part.

For example, the second bobbin may include a second top portion; a second bottom portion disposed below the top portion; and a second middle portion disposed between the second top portion and the second bottom portion, wherein the first bobbin is formed at least partially in a recess defined by a lower surface of the second top portion and an inner surface of the second middle portion. can be accepted.

For example, the first extension part may face a lower surface of the second bottom part.

In addition, a flat panel display device according to an embodiment includes a power supply unit having a transformer disposed thereon, wherein the transformer includes: a core part including an upper core and a lower core; a coil part partially disposed within the core part; and a bobbin part disposed between the core part and the coil part, wherein the coil part includes a first coil and a second coil having at least a part disposed on a side surface of the first coil, An outer foot portion, a second outer foot portion, and a midfoot portion disposed between the first outer foot portion and the second outer foot portion, wherein the shortest distance between the first coil and the second coil is the outermost part of the first coil. It may be 0.1 to 0.3 times the shortest distance between adjacent one of the first outer foot and the second outer foot.

In addition, a transformer according to another embodiment includes a core portion including an upper core and a lower core; a coil part partially disposed within the core part; a bobbin part disposed between the core part and the coil part; and a plurality of coil fixing parts disposed to surround at least a portion of an upper part and an outer portion of the coil part to fix the coil part to the bobbin part and to insulate the coil part from the core part.

For example, the coil part includes a first coil and a second coil disposed on a side surface of the first coil, and the core part extends in a first direction on a plane and in a second direction crossing the first direction. It may include a first outer foot part spaced apart from each other, a second outer foot part, and a midfoot part disposed between the first outer foot part and the second outer foot part.

For example, the bobbin unit may include a first bobbin including a first plate supporting the first coil upwardly and a first sidewall disposed on an upper surface of the first plate and winding the first coil along an outer circumferential surface; and a second bobbin including a second plate supporting the second coil upwardly, and a second sidewall disposed on an upper surface of the second plate and having the second coil wound along an outer circumferential surface, wherein the first A bobbin may be disposed in a through hole defined by an inner circumferential surface of the second sidewall.

For example, at least some of the plurality of coil fixing parts may be disposed in a portion overlapping the core part in a vertical direction among the upper part and the outer part of the coil part.

For example, at least a part of the plurality of coil fixing parts extends along the first direction within a first accommodating space disposed between the first outer foot part and the middle foot part of the core part, and extends along the upper side of the first coil. A 1-1 coil fixing part disposed to surround the outer surface of the first and second coils; a 2-1 coil fixing part extending along the first direction within the first accommodating space and disposed to surround upper and outer surfaces of the second coil; A 1-2 coil fixing part extending along the first direction in a second accommodating space disposed between the second outer foot part and the mid foot part of the core part and disposed to surround the upper and outer surfaces of the first coil. ; and a 2-2 coil fixing part extending along the first direction within the second accommodating space and disposed to surround upper and outer surfaces of the second coil.

For example, at least some of the plurality of coil fixing parts extend along the first direction within a first accommodating space disposed between the first outer foot part of the core part and the middle foot part, and extend along the first coil. a third coil fixing part disposed to surround an upper side and an outer surface of the second coil; and extending along the first direction within a second accommodating space disposed between the second outer foot part and the mid foot part of the core part, and disposed to surround an upper side of the first coil and an upper side and an outer surface of the second coil. A fourth coil fixing part may be included.

For example, at least some of the plurality of coil fixing parts may further extend by 1 mm to 10 mm compared to the core part on both sides in the first direction.

For example, the plurality of coil fixing parts may include a flexible insulating tape, and the insulating tape may include Kapton, ketone, or polyimide.

For example, the height of the bobbin part may be 100% to 140% of the height of the coil part.

For example, a thickness of each of the plurality of coil fixing parts may be within 90% of a thickness of the first plate or the second plate.

In addition, a flat panel display device according to another embodiment includes a power supply unit in which a transformer is disposed, wherein the transformer includes: a core part including an upper core and a lower core; a coil part partially disposed within the core part; a bobbin part disposed between the core part and the coil part; and a plurality of coil fixing parts disposed to surround at least a portion of an upper part and an outer portion of the coil part to fix the coil part to the bobbin part and to insulate the coil part from the core part.

In the transformer and the flat panel display device including the transformer according to an embodiment, leakage inductance is secured by controlling a separation distance between a primary coil and a secondary coil.

In addition, an insulation distance between the primary coil and the core is secured due to the coupling structure of the first bobbin and the second bobbin, so that leakage inductance can be secured.

In addition, a transformer according to another embodiment and a flat panel display device including the same can be slimmer compared to a general bobbin having an upper plate by replacing the upper part of the bobbin part with a thin coil fixing part.

In addition, it is easy to dissipate heat through a portion where the coil fixing unit is not disposed above the bobbin unit, and even a portion where the coil fixing unit is disposed is advantageous in heat dissipation compared to a general bobbin having an upper plate.

The effects that can be obtained in the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description below. will be.

1A is a perspective view of a transformer according to an exemplary embodiment.
1B is a plan view of a transformer according to an exemplary embodiment.
2 is an exploded perspective view of a transformer according to an exemplary embodiment.
3 is an exploded perspective view of a bobbin unit according to an embodiment.
FIG. 4 is a cross-sectional view of a transformer IZmer according to an embodiment taken along line BB′ of FIG. 1B.
5A is a cross-sectional view of a transformer according to an embodiment taken along line AA′ of FIG. 1B.
FIG. 5B is an enlarged view of part 'C' of FIG. 5A.
6 shows an example of a circuit configuration of a power supply unit of an electronic product.
7 shows a leakage inductance ratio according to a winding spacing ratio of a transformer according to an exemplary embodiment.
8 is a cross-sectional view of a transformer according to another aspect of an embodiment.
9 is a perspective view of a transformer according to another embodiment.
10 is an exploded perspective view of a transformer according to another embodiment.
11 is a perspective view illustrating a state in which a core is excluded from a transformer according to another embodiment.
12 is a plan view of a transformer according to another embodiment.
FIG. 13 is a cross-sectional view of a transformer according to another embodiment taken along line DD′ of FIG. 12 .
14 shows an example of an assembly process of a transformer according to another embodiment.
15 shows an example of an assembly process of a transformer according to another aspect of another embodiment.
16 is a cross-sectional view of a transformer according to another aspect of another embodiment.
17 is a cross-sectional view of a transformer according to a comparative example.
18 shows results of a heating test compared to a comparative example of a transformer according to another embodiment.

Since the present invention can make various changes and have various embodiments, specific embodiments are illustrated and described in the drawings. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms including ordinal numbers such as second and first may be used to describe various components, but the components are not limited by the terms. These terms are only used for the purpose of distinguishing one component from another. For example, a second element may be termed a first element, and similarly, a first element may be termed a second element, without departing from the scope of the present invention. The terms and/or include any combination of a plurality of related recited items or any of a plurality of related recited items.

It is understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle. It should be. On the other hand, when an element is referred to as “directly connected” or “directly connected” to another element, it should be understood that no other element exists in the middle.

In the description of the embodiments, each layer (film), region, pattern or structure is "on" or "under" the substrate, each layer (film), region, pad or pattern. The substrate formed on includes all those formed directly or through another layer. The criteria for upper/upper or lower/lower of each layer will be described based on drawings. In addition, since the thickness or size of each layer (film), region, pattern, or structure in the drawing may be modified for clarity and convenience of description, it does not entirely reflect the actual size.

Terms used in this application are only 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, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in the present application, they should not be interpreted in an ideal or excessively formal meaning. don't

Hereinafter, the embodiment will be described in detail with reference to the accompanying drawings, but the same or corresponding components regardless of reference numerals are given the same reference numerals, and overlapping descriptions thereof will be omitted. In addition, although the embodiment is described using the Cartesian coordinate system, it goes without saying that it can be described using other coordinate systems. In the Cartesian coordinate system, the x-axis, y-axis, and z-axis shown in each figure are orthogonal to each other, but the embodiment is not limited thereto. The x-axis, y-axis, and z-axis may intersect each other.

In addition, considering that the transformer related to the embodiment is mounted on the display device, the thickness (vertical height) of the transformer to contribute to the slimming of the display device may be 14 mm or less, preferably 12 mm or less, more preferably 10 mm or less.

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

1A is a perspective view of a transformer according to an embodiment, and FIG. 1B is a plan view of the transformer according to an embodiment. 2 is an exploded perspective view of a transformer according to an exemplary embodiment. In addition, Figure 3 is an exploded perspective view of the bobbin unit according to an embodiment.

Referring to FIGS. 1A to 3 , a transformer 100 according to an exemplary embodiment may include a core part 110 , bobbin parts 120 and 130 , and terminal parts TM1 and TM2 . Hereinafter, each component will be described in detail.

The core parts 111 and 112 have the characteristics of a magnetic circuit and may serve as a passage for magnetic flux. The core parts 111 and 112 may include an upper core 111 coupled from an upper side and a lower core 112 coupled from a lower side. The two cores 111 and 112 may have a vertically symmetrical shape or an asymmetrical shape. However, in the following description, it is assumed that the shape is vertically symmetrical for convenience of description.

Each of the upper core 111 and the lower core 112 has a flat body and a plurality of leg portions OL1-1, which protrude from the body in the thickness direction (ie, the Z-axis direction) and extend along a predetermined direction. OL1-2, OL2-1, OL2-2, CL1, CL2). For example, the plurality of leg portions OL1-1, OL1-2, and CL1 of the upper core 111 extend along one axis (here, Y-axis) on a plane and along the other axis (here, X-axis) direction. It may include two outer legs OL1-1 and OL1-2 disposed apart from each other, and one midfoot CL1 disposed between the two outer legs OL1-1 and OL1-2.

When the upper core 111 and the lower core 112 are coupled vertically, the outer feet OL1-1 and OL1-2 of the upper core 111 and the midfoot CL1 correspond to each other of the lower core 112. It is opposed to the outer foot (OL2-1, OL2-2) or the middle foot (CL2). The first outer foot pair (OL1-1, OL2-1) facing each other has a first outer foot portion, the other outer foot pair (OL1-2, OL2-2) has a second outer foot portion, and the midfoot pair (CL1, CL2) has a midfoot portion, respectively. can be called

A gap of a predetermined distance (eg, 10 to 200 μm, but is not necessarily limited thereto) may be formed between at least some of the outer or midfoot pairs that face each other. The inductance of the core unit 110 can be controlled by adjusting the size of each of the gaps of one midfoot pair and two outfoot pairs, and heat generation can be controlled according to the number of gaps.

In addition, the core part 110 may include a magnetic material such as iron or ferrite, but is not necessarily limited thereto.

Since the core part 110 surrounds a part of the outer side of the bobbin parts 120 and 130, a part of the primary coil (not shown) and the secondary coil (not shown) accommodated in the bobbin part 120 and 130 is the core part. (110).

The bobbin parts 120 and 130 may include a first bobbin 120 and a second bobbin 130 .

The first bobbin 120 and the second bobbin 130 have a first through hole TH1 and a second through hole TH2, respectively, and the midfoot parts CL1 and CL2 of the core part 110 have the first through hole. They may be aligned to pass through the hole TH1 and the second through hole TH2.

At least a portion of the first bobbin 120 may be accommodated in the second bobbin 130 and may include a first top portion 121 , a first middle portion 123 , and a first bottom portion 122 .

The first top portion 121 and the first bottom portion 122 may each have a rectangular planar shape with rounded corners, but are not necessarily limited thereto. In addition, the first bottom portion 122 may have a planar shape extending outward along a direction in which the leg portion is separated from the first top portion 121 (ie, the X-axis direction).

The first middle part 123 is disposed between the first top part 121 and the first bottom part 122 in the vertical direction, and can insulate between a conductive wire (not shown) constituting the primary coil and the middle foot part. there is. The space defined by the lower surface of the first top portion 121, the outer surface of the first middle portion 122, and a portion of the upper surface of the first bottom portion may function as an accommodation space for accommodating the conductive wire constituting the primary coil.

The second bobbin 130 may include a second top portion 131 , a second middle portion 133 , a second bottom portion 132 , and substrate support portions CBS1 and CBS2 .

The second middle part 133 is disposed between the second top part 131 and the second bottom part 132 in the vertical direction, and the conductive wire (not shown) constituting the secondary coil and the conductive constituting the primary coil It is possible to insulate between lines (not shown). A space defined by a part of the lower surface of the second top part 131, an outer surface of the second middle part 132, and a part of the upper surface of the second bottom part can function as an accommodation space for accommodating the conductive wire constituting the secondary coil.

In addition, the board support parts CBS1 and CBS2 spaced apart from each other in the long axis direction of the second bottom part 132 perform a function of supporting the transformer 100 when mounted on a circuit board (not shown) of a device such as a PSU. can do.

Terminal parts TM1 and TM2 may be disposed at both ends of the second top part 132 in the direction of the long axis. The terminal units TM1 and TM2 have a function of fixing the transformer 100 to a substrate (not shown) of the power supply unit (PSU), and a primary coil and a secondary coil (not shown) of the transformer 100 and the power supply unit (PSU) of the substrate (not shown) may perform the function of the electrical connection passage.

In more detail, the first terminal unit TM1 may include a plurality of pins spaced apart from each other, and either end of a conductive line constituting the primary coil may be electrically connected to at least some of the plurality of pins. The second terminal unit TM2 may include a plurality of pins spaced apart from each other, and either end of a conductive line constituting the secondary coil may be electrically connected to at least some of the plurality of pins.

When configuring the transformer 100, at least a part of the first bobbin 120 is a recess (RC) defined by the lower surface of the second top part 131 of the second bobbin 130 and the inner surface of the second middle part 133. ) can be accommodated. In addition, in a state in which the first bobbin 120 and the second bobbin 130 are coupled, the upper surface of the first top part 121 faces the lower surface of the second top part 131, and the first bottom part 122 Of the upper surface of the , a portion that does not overlap with the first top portion 121 in the vertical direction (ie, a portion extending outward) faces the lower surface of the second bottom portion 132 . In addition, the coil lead-out portion 124 of the first top portion 121 may pass through the third through hole TH3 of the second top portion 131 in a coupled state and be exposed upward. The coil lead-out portion 124 facilitates drawing and fixing of both ends of the conductive wire constituting the primary side coil to the upper surface of the second top portion 131, enabling direct connection to the first terminal portion TM1.

An accommodating state of each of the primary coil and the secondary coil due to the coupling structure of the bobbin parts 120 and 130 described above will be described with reference to FIGS. 4 to 5B.

4 is a cross-sectional view of a transformer according to an exemplary embodiment taken along line BB′ of FIG. 1B.

Referring to FIG. 4 , bobbin parts 120 and 130 are disposed between the core part 110 and the coil parts 140 and 150 .

In more detail, the coil parts 140 and 150 and the bobbin parts 120 and 130 are partially disposed across the first space SP1 and the second space SP2 in the core part 110 . The first space SP1 and the second space SP2 are spaced apart along the direction in which the leg parts are spaced apart from each other (ie, the X-axis direction) with the midfoot parts CL1 and CL2 interposed therebetween, and the cross-sectional shape of the square is Y. It may have a shape extending along the axial direction. In addition, the first space SP1 is located between the midfoot parts CL1 and CL2 and one outer foot part OL1-1 and OL2-1 of the core part 110, and the second space SP2 is the midfoot part ( CL1, CL2) and the other outer foot (OL1-2, OL2-2).

The first bobbin 120 includes a first accommodating part RP1 accommodating the primary side coil 140, and a first extension part EP1 extending from the first accommodating part RP1 toward the second bobbin 130. can have That is, the first accommodating portion RP1 may correspond to portions of the first top portion 121 , the first middle portion 123 , and the first bottom portion 122 excluding the first extension portion EP1 .

The second bobbin 130 includes a second accommodating part RP2 accommodating the secondary side coil 150 and a second extension part EP2 extending from the second accommodating part RP2 toward the first bobbin 120 . can have That is, the second accommodating portion RP2 may include a portion of the second top portion 131 excluding the second extension portion EP2 , the second middle portion 133 , and the second bottom portion 132 .

Also, the second accommodating part RP2 is disposed on the first extension part EP1, and the first accommodating part RP1 is disposed below the second extension part EP2. Due to this, the shortest distance h1 from the lower surface of the lower core 112 to the primary coil 140 is different from the shortest distance h2 from the lower surface of the lower core 112 to the secondary coil 150. . That is, the shortest distance h1 from the lower surface of the lower core 112 to the primary coil 140 is smaller than the shortest distance h2 from the lower surface of the lower core 112 to the secondary coil 150 . For example, the shortest distance h1 between the lower surface of the lower core 112 and the primary coil 140 is 0.3 to 0.7 times the shortest distance h2 between the lower surface of the lower core 112 and the secondary coil 150. it can be a boat

In addition, due to the above-described coupling structure of the bobbin parts 120 and 130, the primary side coil 140 and the secondary side coil 150 only partially overlap in the direction from one outer foot part to the other outer foot part, and the other part does not overlap. . In the vertical direction, the primary coil 140 and the secondary coil 150 may not overlap each other.

At least a part of the secondary coil 150 is disposed on the side surface of the primary coil 140, and between the primary coil 140 and the secondary coil 150 in the horizontal direction, a part of the second accommodating part RP2, That is, the second middle part 133 is disposed.

Each of the primary-side coil 140 and the secondary-side coil 150 may be multiple windings in which a rigid conductor metal, for example, copper, is wound several times, but is not necessarily limited thereto. In addition, the thickness of the conductive wire constituting the secondary coil 150 may be 50% to 150% of the thickness of the conductive wire constituting the primary coil 140, but is not necessarily limited thereto.

Meanwhile, insulating parts 161 and 162 may be respectively disposed between the bobbin parts 120 and 130 and both outer feet. The insulating parts 161 and 162 extend outwardly from the upper surface of the second accommodating part RP2 and then are bent to cover the outside of the second accommodating part RP2 and the first extension part EP1 again. 1 may be bent and extended to the lower surface of the extension part EP1. Through this, both the secondary side coil 150 and the primary side coil 140 may be insulated from the outer foot portion of the core unit 110 . The insulating parts 161 and 162 may include components such as ketone and polyimide having excellent insulating properties, but are not necessarily limited thereto.

Due to having the above structure, the insulation distance of the primary side coil 140 with respect to the core part 110 can be greatly increased. For example, the first insulation distance PATH1 to the upper side of the primary side coil 140 directly reaches the lower surface of the upper bobbin if there was no second extension part EP2, but due to the presence of the second extension part EP2, at least It extends by the length of the second extension in the x-axis direction. In addition, the second insulation distance PATH2 to the lower side of the primary coil 140 is extended by the length of the first extension EP1 in the x-axis direction and the length of the insulation parts 161 and 162 in the same direction. be able to

In addition, with the leakage inductance obtained simply by the shortest distance β between the primary coil 140 and the secondary coil 150 between the primary coil and the secondary coil, the first accommodating part RP1 and the second Additional leakage inductance may be secured by the displacement of the accommodating part RP2 in the horizontal direction.

Hereinafter, with reference to FIGS. 5A and 5B , a cross section of a portion not covered by the core part 110 will be examined.

5A is a cross-sectional view of a transformer according to an exemplary embodiment taken along line A-A' in FIG. 1B, and FIG. 5B is an enlarged view of portion 'C' in FIG. 5A.

Referring to FIGS. 5A and 5B together, the first extension part EP1 of the first bobbin 120 may not be disposed in a portion where the bobbin parts 120 and 130 are not covered by the core part 110. . In addition, the primary side coil unit 140 and the secondary side coil unit 140 are located outside the bobbin units 120 and 130 at a portion not covered by the core unit 110, that is, outside the first space SP1 and the second space SP2. The shortest distance α between the coil parts 150 is the shortest distance between the primary coil part 140 and the secondary coil part 150 at the part where the bobbin parts 120 and 130 are wrapped by the core part 110. It may be the same as (β) or it may be different.

Preferably, the shortest distance ratio (β/α) may be between 1 and 1.3. When the shortest distance ratio (β/α) is less than 1, the overall size of the transformer 100 is increased, and the leakage inductance change is not large. Conversely, when the shortest distance ratio (β/α) exceeds 1.3, the energy conversion efficiency of the transformer 100 decreases. However, this range corresponds to when the A-A' incision line and the B-B' incision line of FIG. 1B intersect at the center of the midfoot on a plane, and the shortest distance ratio (β/α) is between the first middle part 123 and the second middle part. It may be different according to the radius of curvature of the section 133 in the winding direction.

Hereinafter, the transformer 100 according to the embodiment will be described with reference to FIG. 6 along with a circuit configuration in which the transformer 100 can be mounted.

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

Referring to FIG. 6 , a circuit configuration of a power supply unit (ie, PSU) of an electronic product including a square wave generator 210, a resonance unit 220, and a rectifier 230 is shown. Flat-panel TVs generally support other operating modes such as a low power mode in addition to the normal mode, and since high efficiency is required for each operating mode, the resonator 220 is implemented in the form of an LLC resonant converter. The LLC resonant converter includes a first inductor (Lr, 221), a second inductor (Lm, 222), and a capacitor (Cr, 223). can see. The resonance frequency varies according to the operating frequency of the PSU, and factors determining the operating frequency include the inductance Lr of the first inductor 221 and the capacitance Cr of the capacitor 223. If the inductance (Lr) of the first inductor 221 and the capacitance (Cr) of the capacitor 223 do not match to an appropriate value, the efficiency of the entire circuit may decrease or a situation in which normal operation is impossible may occur.

The inductance (L) value of the leakage inductance-integrated transformer, such as the transformer 100 according to the embodiment, corresponds to Lm in the resonator 220, and the leakage inductance (Lk) value corresponds to Lr.

Although the Lk/Lm ratio required for a PSU of a typical flat-panel TV is 10 to 20%, conventional transformers have a very low Lk value, making it difficult to satisfy this requirement.

More specifically, the leakage inductance of the transformer can be obtained as shown in Equation 1 below.

In Equation 1, Lk represents the leakage inductance, k represents the coupling coefficient, and Lm represents the inductance of the transformer. Here, the coupling coefficient (k) may be obtained by experimentation, and as an example, it may be obtained as shown in Equation 2 below.

In Equation 2, X is the winding separation ratio, the shortest distance between the outermost part of the primary coil defining the space in which the secondary coil can be wound (hereinafter referred to as "winding space" for convenience) and the adjacent outer leg, the primary coil and 2 It means the separation distance of the secondary coil.

More specifically, when both the first bobbin 120 and the second bobbin 130 exist, the shortest distance between the primary coil 140 and the secondary coil 150 (ie, β in FIG. 4 ) is the primary coil ( 140) and the innermost side of the secondary coil 150. In addition, assuming that only the first bobbin 120 exists, the maximum value of the distance that can be achieved with the primary coil 140 within the winding space in which the secondary coil 150 can exist is the primary coil 140 is the shortest distance (ie, d1 in FIG. 4) from the outermost part of to the adjacent outer leg.

The leakage inductance of the transformer changes according to the coupling coefficient, and the coupling coefficient is particularly affected by the shortest distance between the primary coil 140 and the secondary coil 150 inside the core unit 110 .

However, the shortest distance β between the primary coil 140 and the secondary coil 150 is determined depending on where the innermost part of the secondary coil 150 is located in the winding space, and the shortest distance β Considering only the increase in the winding space, the number of turns of the secondary coil 150 is limited when the winding space is fixed, and since the size of the core part 110 must be increased to increase the winding space, it is difficult to approach from the viewpoint of expanding the winding space.

Therefore, in this embodiment, the ratio of the shortest distance (β) between the primary coil 140 and the secondary coil 150 to the shortest distance d2 from the outermost part of the primary coil 140 to the adjacent outer leg, that is, , the leakage inductance is secured by controlling the winding gap ratio.

7 and Table 1 below show changes in leakage inductance according to the shortest distance β between the primary coil 140 and the secondary coil 150 according to the experiment and the winding separation ratio. In the experiment, the primary coil 140 was a two-layer winding of 0.1Ψ * 40 strands and a 0.75 mm thick conductive wire, and the secondary coil 150 was a 0.08Ψ * 210 strand of 1.4 mm thick conductive wire. this was used

β [mm] β /d1 L _m [uH] L _L [uH] L _L /L _m 1.3 6.80% 299 35.5 11.90% 2.9 15.30% 299 50.3 16.80% 5.7 30.00% 299 59.9 20.00% 8.4 44.20% 299 67 22.40%

In FIG. 7 , the horizontal axis represents the winding gap ratio, and the vertical axis represents the ratio (LL ratio) of the leakage inductance (LL) to the self inductance (Lm) of the transformer 100, respectively. Referring to FIG. 7 and Table 1, as the gap ratio increases, the ratio of the leakage inductance (LL) to the self inductance (Lm) of the transformer 100 is in the form of a logarithmic function (eg, y = 0.0556ln (x) with a 0.997 approximation) +0.2693, which can be modeled).

However, the shortest distance β between the primary coil 140 and the secondary coil 150 is preferably 0.1 to 0.3 times d1. If the ratio is less than 0.1 times, the LLC matching of the board of the circuit (eg, PSU) on which the transformer is mounted is out of alignment and the operating frequency rises, which can cause a problem in which the board cannot be controlled. This is because it reduces efficiency and can cause oscillations on the board. However, this is an example assuming a general PSU and is not necessarily limited thereto depending on the mounting circuit.

Consequently, referring to Equations 1 and 2, the leakage inductance is affected by the coupling coefficient k, and the coupling coefficient is affected by the distance between the primary coil and the secondary coil and the overlapping area. The transformer 100 according to the embodiment lowers the coupling coefficient by controlling the separation distance between the primary coil and the secondary coil in order to increase the leakage inductance, and moves the primary coil accommodating space and the secondary coil accommodating space in the horizontal direction. By shifting to , leakage inductance was additionally secured.

Therefore, since the transformer according to the embodiment can secure a high Lk value while being slim due to the bobbin unit coupling structure described above, it is suitable for constructing a power supply unit of a flat-panel TV.

In the transformer 100 according to the embodiment described so far, due to the coupling structure of the bobbin parts 120 and 130, the second accommodating part RP2 is at least in the portion surrounded by the core part 110, and the first extension part ( EP1), and the first accommodating part RP1 is disposed under the second extension part EP2 so that the first accommodating part RP1 and the second accommodating part RP2 do not overlap at least partially in the horizontal direction. . However, according to another aspect of an embodiment, a space accommodating the primary coil 140 and a space accommodating the secondary coil 150 may be parallel. This will be described with reference to FIG. 8 .

8 is a cross-sectional view of a transformer according to another aspect of an embodiment.

In FIG. 8 , the primary coil 140, the secondary coil 150, the first bobbin 120', and the second bobbin 130' in the transformer 100' are surrounded by the core part 110. A cross section is shown. In addition, although the illustration of the insulating parts 161 and 162 is omitted in FIG. 8 for easy understanding, the transformer 100' according to another aspect may also include the insulating parts 161 and 162 as a matter of course.

The first bobbin 120' provides a first accommodating space RS1 accommodating the primary coil 140, and the second bobbin 130' provides a second accommodating space accommodating the secondary coil 150 ( RS2) is provided.

The second bobbin 130' extends between the midfoot parts CL1 and CL2 to the first outer foot parts OL1-1 and OL1-2 and between the midfoot parts CL1 and CL2 to the second outer foot parts OL2-1 and OL2-2. ) It may be disposed on the outside of the first bobbin 120 'between.

In addition, the first accommodating space RS1 and the second accommodating space RS2 are separated from the first outer leg parts OL1-1 and OL1-2 of the core part 110 to the second outer foot parts OL2-1 and OL2-2. ) direction, at least a portion may overlap. For example, the first accommodating space RS1 and the second accommodating space RS2 may be parallel, but are not necessarily limited thereto.

As the accommodating spaces RS1 and RS2 overlap, the primary coil 140 and the secondary coil 150 also move from the first outer leg portions OL1-1 and OL1-2 to the second outer leg portions OL2-1 and OL2. At least a part may overlap in the -2) direction.

Preferably, in the transformer 100' according to the other aspect, the winding spacing ratio, that is, the shortest distance d2 from the outermost outermost part of the primary coil 140 to the adjacent outer leg, the primary coil 140 and the secondary coil The ratio (β'/d2) of the shortest distance (β') between (150) may be 0.1 to 0.3.

Also, similar to the transformer 100 according to one embodiment, in the transformer 100' according to another aspect, the primary side coil part is located where the bobbin parts 120' and 130' are not covered by the core part 110. The shortest distance between the 140 and the secondary coil unit 150 is the primary coil unit 140 and the secondary coil unit 150 at the part where the bobbin units 120' and 130' are wrapped by the core unit 110. ) may be the same as or different from the shortest distance (β′) between Preferably, the shortest distance ratio (β/α) may be between 1 and 1.3.

Hereinafter, transformers 300 and 300' according to other embodiments will be described in detail with reference to the accompanying drawings.

9 is a perspective view of a transformer according to another embodiment, and FIG. 10 is an exploded perspective view of the transformer according to another embodiment.

9 and 10 together, a transformer 300 according to another embodiment includes a core part 310, bobbin parts 320 and 330, a first coil 340, a second coil 350, a first Coil fixing parts 361 , 362 , 363 , and 364 and second coil fixing parts 371 , 372 , 373 , and 374 may be included. Hereinafter, each component will be described in detail.

Since the core parts 311 and 312 are similar to the configuration of the core parts 111 and 112 described above in one embodiment, overlapping descriptions will be omitted.

In the core parts 311 and 312 according to another embodiment, when the upper core 311 and the lower core 312 are vertically coupled, a first accommodating space is disposed between the first outer foot part and the mid foot part, and the second A second accommodating space may be disposed between the outer foot portion and the midfoot portion.

The bobbin parts 320 and 330 may include a first bobbin 320 and a second bobbin 330 .

The first bobbin 320 and the second bobbin 330 have a first through hole TH1 and a second through hole TH2, respectively, and the midfoot parts CL1 and CL2 of the core part 310 have a first through hole. It passes through the hole TH1, and the first bobbin 120 may be aligned to be accommodated in the second through hole TH2.

Each of the first bobbin 320 and the second bobbin 330 has a long axis extending along a direction in which each of the midfoot part and the outer foot part extends (ie, the Y-axis direction) on a plane, and the midfoot part and the outer foot part each other on a plane. It may have a minor axis extending in a spaced apart direction (ie, an X-axis direction).

The first bobbin 320 may include a first sidewall 321 and a first plate 322 disposed at a lower end of the first sidewall 321 .

The first sidewall 321 may have a rectangular planar shape with rounded corners, and the first plate 322 may have a quadrangular annular planar shape with rounded corners, but are not necessarily limited thereto.

The first sidewall 321 may insulate the midfoot portions CL1 and CL2 from the first coil 340 . In addition, the inner circumferential surface of the first sidewall 321 defines the first through hole TH1, and the first coil 340 may be wound along the outer circumferential surface.

The first plate 322 may insulate the lower core 322 and the first coil 340 and support the first coil 340 upward.

The second bobbin 330 may include a second sidewall 131 and a second plate 132 disposed at a lower end of the second sidewall 131 .

The second sidewall 331 may have a rectangular planar shape with rounded corners, and the second plate 332 may have a quadrangular ring-shaped planar shape with rounded corners, but are not limited thereto.

The second sidewall 331 may insulate the first coil 340 and the second coil 350 . In addition, the inner circumferential surface of the second sidewall 331 defines the second through hole TH2, and the second coil 350 may be wound along the outer circumferential surface.

The second plate 332 may insulate the lower core 322 and the second coil 350 and support the second coil 350 upward.

Each of the first coil 340 and the second coil 350 may be multiple windings in which a rigid conductor metal, for example, a copper conductive wire, is wound several times, but is not necessarily limited thereto. In addition, the thickness of the conductive wire constituting the second coil 350 may be 50% to 150% of the thickness of the conductive wire constituting the first coil 340, but is not necessarily limited thereto. Also, in the transformer 300 according to the embodiment, the first coil 340 may correspond to the primary coil, and the second coil 150 may correspond to the secondary coil, but is not necessarily limited thereto. In addition, the two ends of the conductive wire constituting the first coil 340 and the two ends of the conductive wire constituting the second coil 350 may be pulled out in opposite directions, but these drawing directions are exemplary and must be taken into account. It is not limited.

Meanwhile, coil fixing parts 361, 362, 363, 364, 371, 372, 373, and 374 may be disposed on at least a part of the upper part and the outer circumferential surface of each of the first coil 140 and the second coil 350. The coil fixing parts 361, 362, 363, 364, 371, 372, 373, and 374 may include a material having insulation and flexibility. For example, the coil fixing unit may include an insulating tape including kapton, ketone, polyimide, and the like. As another example, the coil fixing part may be made of polymer molding such as epoxy or adhesive bonding, but if it can fix each of the first coil 340 and the second coil 350 and at least insulate it from the core part 310, this must be done. It is not limited.

The coil fixing part may include first coil fixing parts 361 , 362 , 363 , and 364 and second coil fixing parts 371 , 372 , 373 , and 374 .

The first coil fixing parts 361, 362, 363, and 364 may be disposed on at least a part of the upper surface and the outer circumferential surface (or upper and outer surfaces) of the first coil 340 to fix and insulate the first coil 340. .

In addition, the second coil fixing parts 371 , 372 , 373 , and 374 are disposed on at least a part of the upper surface and the outer circumferential surface (or upper and outer surfaces) of the second coil 350 to fix and insulate the second coil 350 . can

Hereinafter, the coil fixing part will be described in detail with reference to FIGS. 11 to 13 . 11 is a perspective view illustrating a state in which a core is excluded from a transformer according to another embodiment.

Referring to FIG. 11 , the first coil fixing parts 361, 362, 363, and 364 extend along the long axis direction (ie, the Y-axis direction) of the first bobbin 320 and face each other in the 1-1 coil core. The top 361 and the 1-2 coil fixing portion 362 and the 1-3 coil fixing portion 363 extending along the minor axis direction (ie, the X-axis direction) of the first bobbin 320 and facing each other and 1-4 coil fixing parts 364 .

In addition, the second coil fixing parts 371, 372, 373, and 374 extend along the long axis direction (ie, the Y-axis direction) of the second bobbin 330 and are 2-1 coil fixing parts 371 facing each other. and the 2-2nd coil fixing part 372, the 2-3rd coil fixing part 373 and the 2nd-3rd coil fixing part 373 extending along the minor axis direction (ie, the X-axis direction) of the second bobbin 330 and facing each other. A 4-coil fixing part 374 may be included.

FIG. 12 is a plan view of a transformer according to another embodiment, and FIG. 13 is a cross-sectional view of a transformer according to another embodiment taken along line D-D' in FIG. 12 .

In the plan view shown in FIG. 12, a shape in which the upper core 311 is removed from the transformer 300 according to another embodiment is shown for ease of understanding. Referring to FIG. 12 , for reliable insulation from the core part 310, the 1-1st coil fixing part 361, the 2-1st coil fixing part 371, the 1-2nd coil fixing part 362, and It is preferable that each of the 2-2nd coil fixing parts 372 further extends from the core part 310 by a predetermined length d4 in an extension direction (ie, Y-axis). For example, d1 may be 1 mm to 10 mm, but is not necessarily limited thereto.

Meanwhile, the extension direction (ie, X-axis direction) of the coil fixing parts 363, 364, 373, and 374 extending along the minor axis direction (ie, X-axis) of the first bobbin 320 and the second bobbin 330 The length of may be determined according to the width of the corresponding coil. For example, the length d5 of the second-third coil fixing part 373 in the extending direction may be 1/5 to 1/3 of the width d6 of the second coil 150 in the corresponding direction. This is because, when the d5/d6 ratio is less than 1/5, coil fixation is weakened, and when it is greater than 1/3, the area covered by the coil fixing part increases and heat dissipation is hindered. However, it is obvious to those skilled in the art that the above ratio is exemplary and can be changed within a range capable of securing heat dissipation performance and stability.

The number and arrangement of the coil fixing units described above with reference to FIGS. 11 and 12 are examples, and are not necessarily limited thereto. For example, the 1-3 coil fixing part 363, the 2-3 coil fixing part 373, the 1-4 coil fixing part 364, and the 2-4 coil fixing part 374 are the first bobbin ( 320) and the second bobbin 330 are disposed at the center of each minor axis direction, but at least some of the coil fixing parts 363, 364, 373, and 374 may be divided into two or more and disposed spaced apart from each other along the minor axis direction. there is.

However, the first coil 340 and the second coil 350 are in a direction perpendicular to the core portion 310 among the first coil 340 and the second coil 350 so that the first coil 340 and the second coil 350 may be insulated from the core portion 110 . It is preferable that the coil fixing part be always disposed in the overlapping portion. This will be described with reference to FIG. 13 .

Referring to FIG. 13, the 1-1 coil fixing part 361 disposed in the first accommodation space between the first outer foot parts OL1-1 and OL2-1 and the mid-foot parts CL1 and CL2 and the second - 1 coil fixing part 371, and the 1-2 coil fixing part 362 disposed in the second accommodating space between the second outer foot parts OL1-2 and OL2-2 and the midfoot parts CL1 and CL2 The 2-2nd coil fixing part 372 is preferably provided without fail.

Meanwhile, the thickness of each of the coil fixing parts 361, 362, 363, 364, 371, 372, 373, and 374 may be 90% or less of the thickness t of the first plate 322 or the second plate 332. . In addition, the height h3 of the bobbin parts 320 and 330 may be equal to or less than 140% of the height h4 of the primary coil 340 or the secondary coil 350 . For example, if the height h4 of the coils 340 and 350 is 1.8 cm, the height of the bobbin may be 1.8 cm to 2.52 cm.

14 shows an example of an assembly process of a transformer according to another embodiment.

14 shows a form in which the 2-2 coil fixing part 372 is disposed. Specifically, the 2-2 coil fixing part 372 is the second plate 331 through the upper surface and outer circumferential surface of the second coil 350 in order from the upper surface of the second sidewall 331 of the second bobbin 130. It can be attached to wrap around the sides in sequence. The order of attachment may be different from the order shown in FIG. 14, and for stronger fixing and insulation, the 2-2 coil fixing part 372 is formed from the upper surface of the second side wall 331 to the inner circumferential surface of the second side wall. It may extend to at least a part, or may extend to at least a part of the bottom surface from the side of the second plate 332 .

According to another aspect of another embodiment, one coil fixing unit may fix and insulate the first coil 340 and the second coil 350 together. This will be described with reference to FIGS. 15 and 16 .

15 shows an example of an assembly process of a transformer according to another aspect of another embodiment, and FIG. 16 is a cross-sectional view of a transformer 300' according to another aspect of another embodiment.

Referring to FIGS. 15 and 16 together, in a state in which the bobbin parts 320 and 330, the first coil 340, and the second coil 350 are assembled, one coil fixing part 382 is a second bobbin 330 ) through the upper surface of the first sidewall 321, the upper surface of the first coil 340, the upper surface of the second sidewall 331, the upper surface of the second coil 350, and the outer circumferential surface of the second coil 350 in order. It may be attached to cover the side of the plate 331 in order. The order of attachment may be different from the order shown in FIG. 15, and for stronger fixation and insulation, the coil fixing part 382 extends from the upper surface of the first sidewall 131 to at least a part of the inner circumferential surface of the first sidewall. Alternatively, it may extend from the side of the second plate 332 to at least a part of the bottom surface.

As shown in FIG. 15, the way in which one coil fixing unit fixes the first coil 340 and the second coil 350 together is in the direction of the short axis of the coil fixing unit 382 and the bobbin units 320 and 330 shown. Positions facing each other along (ie, positions 361 and 371) and two long shaft ends facing each other along the long axis direction of bobbin parts 320 and 330 (ie, positions 363 and 373 and 364 and 374) Of course, it can be applied. For example, one coil fixing part 381 is disposed at positions opposite to each other (ie, positions 361 and 371) along the short axis direction of the coil fixing part 382 and the bobbin parts 320 and 330 shown in FIG. 15 . The form is as shown in Figure 16.

Hereinafter, effects of the transformers 300 and 300' according to other embodiments will be described through comparison with the transformer 300" according to the comparative example with reference to FIGS. 17 and 18.

17 is a cross-sectional view of a transformer according to a comparative example.

Referring to FIG. 17 , in the transformers 300 and 300' according to another embodiment, at least some upper surfaces of the first coil 340 and the second coil 350 are coil fixing parts 361, 362, 363, 364, and 371 , 372, 373, 374, 381, 382), but in the transformer 300" according to the comparative example, the upper plate 333" is disposed on the bobbin parts 320" and 330", and the first coil 340 and the second coil 350 are fixed and insulated.

In this case, the first coil 340 and the second coil 350 of the transformer 300" according to the comparative example have the same configuration as the transformer 300 according to another embodiment and have the same accommodation space inside. Assuming, the size of the transformer 300 "according to the comparative example is inevitably increased.

For example, the size of the space RS1 in which the first coil 340 is accommodated in FIG. 13 and the space RS2 in which the second coil 350 is accommodated in FIG. Assuming that the size of the space RS1" and the space RS2" accommodating the second coil 350 are the same, the upper plate 333" has a thickness of the first plate 322 and the second plate 332". Assume that it is equal to the thickness t of ) In this case, in the transformer 300 according to another embodiment, in order to secure the same size of accommodating spaces RS1 and RS2, the height of the bobbin parts 320 and 330 in the vertical direction ( h3) and the height of the accommodating space in the core part 310 corresponding to the sum of the thickness of the coil fixing part is required as a minimum. On the other hand, in the transformer 300" according to the comparative example, the accommodating space RS1" of the same size is required. , RS"), the minimum height of the accommodation space in the core part 310" by h3+t is required.

In other words, the height of the accommodating space required in the core part 310 of the transformer 300 according to another embodiment is compared to the height of the accommodating space required in the core part 310" of the transformer 300" according to the comparative example " as low as t-core fixture thickness". Here, since the thickness of the core fixing part is 90% or less compared to t as described above, the height of the transformer 300 according to another embodiment can be reduced by at least 0.1t compared to the comparative example, and further slimming is possible.

In addition, since the upper plate (eg, 333") of the bobbin parts 320" and 330" according to the comparative example is integrally formed with the rest of the bobbin part, it is composed of the same hard polymer resin. Therefore, the first coil 340 and the flexible change of the accommodating spaces (RS1", RS2") of the second coil 150 is difficult, so that the standards of the first coil 340 and the second coil 350 are changed according to the standards of the bobbin parts 320" and 330". Strictly limited.

On the other hand, in the transformer 300 according to another embodiment, since the coil fixing part has flexibility, winding and fixing are possible even if the specifications of the first coil 340 and the second coil 350 are slightly changed.

In addition, when current flows through the first coil 340 and the second coil 350, heat is generated and resistance increases. Since the entire top surfaces of the first coil 340 and the second coil 350 are covered with an upper plate (eg, 333"), heat dissipation is difficult. As heat dissipation becomes difficult, heat generation increases, and the increase in heat generation leads to an increase in resistance of the coil, and the increase in resistance causes an increase in loss, resulting in a decrease in efficiency.

On the other hand, since the transformers 300 and 300' according to other embodiments have flexibility and do not cover the entire top surfaces of the first coil 340 and the second coil 350, they are stored in the accommodation space within the core part 310. It increases the heat transfer path (heating pass) and is also advantageous for heat dissipation.

The effect of excellent heat dissipation will be described with reference to FIG. 18 and Table 2 together.

18 shows results of a heating test compared to a comparative example of a transformer according to another embodiment. In (a), (c) and (e) of FIG. 18, the upper core 311 is shown removed for better understanding, but it should be noted that the experiment proceeded with the upper core 311 also coupled. .

18(a) shows a transformer 300" according to a comparative example, and FIG. 18(b) shows a thermal image of the transformer shown in FIG. 18(a). In addition, FIG. In (c), a modified comparative form in which only the upper plate of the first bobbin 320 "is replaced with a core fixing part in the transformer according to the comparative example is shown, and in FIG. 18(d), it is shown in FIG. 18(c) A thermal image of the transformer is shown. In addition, FIG. 18(e) shows a transformer 300 according to another embodiment, and FIG. 18(f) shows thermal images of the transformer 300 according to another embodiment.

Table 2 below summarizes the experimental results for each case shown in FIG. 18 .

Sample No. comparison Transformation comparison another embodiment Core Size(mm) 60 x 50 60 x 50 60 x 50 Inductance(uH) 298.6 311.9 323.2 Leakage Inductance 41.8 48.28 40 Q (quality factor) 119 122 140 Upper surface of the core 67.1 60.9 58 core side 69 62 61.2 1st coil 61.9 60.9 58.3

Referring to FIG. 18 and Table 2 together, it can be seen that the temperature of both the core part and the first coil decreases from Comparative Examples to other Examples under the same operating conditions. In addition, it can be seen that the Q factor increases as the loss decreases due to the decrease in temperature.

Although the embodiments have been described above, these are only examples and do not limit the present invention, and those skilled in the art to which the present invention belongs will not deviate from the essential characteristics of the present embodiment. It will be appreciated that various variations and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. And the differences related to these modifications and applications should be construed as being included in the scope of the present invention as defined in the appended claims.

100: transformer 110: core part
120: first bobbin 130: second bobbin
140: primary coil 150: secondary coil
161, 162: insulator
300, 300': transformer 310: core part
320: first bobbin 330: second bobbin
340: first coil 350: second coil
361, 362, 363, 364, 371, 372, 373, 374, 381, 382: coil fixing part

Claims (16)

a core portion including an upper core and a lower core disposed in a first direction facing the upper core;
a coil part at least partially disposed within the core part; and
It includes; a bobbin part disposed between the core part and the coil part,
the core part,
A first outer foot portion, a second outer foot portion, and a midfoot portion disposed between the first outer foot portion and the second outer foot portion;
The coil part,
Including a first coil and a second coil disposed spaced apart from each other in a second direction crossing the first direction,
The bobbin part,
a first bobbin having a first accommodating part accommodating the first coil; and
A second bobbin having a second accommodating portion accommodating the second coil,
At least a part of the first bobbin is accommodated inside the second bobbin,
The second bobbin,
a first terminal part electrically connected to the first coil; and
A second terminal part electrically connected to the second coil; includes,
The first terminal part,
first pin connection regions each connected to one end of a plurality of first terminal pins;
A first pin protruding area protruding from the first pin connection area;
The second terminal part,
second pin connection regions respectively connected to one end of a plurality of second terminal pins;
A second pin protrusion area protruding from the second pin connection area;
A protruding direction of the first pin protruding area and a protruding direction of the second pin protruding area cross each other. According to claim 1,
The first pin protruding area protrudes in the second direction;
The second pin protrusion area protrudes in a third direction crossing the first direction and the second direction simultaneously. According to claim 2,
At least one pair of the first pin protruding regions are disposed to face each other with the second bobbin interposed therebetween. According to claim 3,
The first terminal portion includes a first bent portion having an end bent in the first direction from the first pin protruding region,
The second terminal part includes a second bent part having an end bent in the second direction from the second pin protruding area. According to claim 4,
At least one pair of the first bent portions overlaps at least a portion of each other in the second direction. According to claim 5,
The first bent part overlaps at least a portion of the coil part and the bobbin part in the second direction. According to claim 6,
At least one pair of the first bent portions overlaps at least a portion of each other in the third direction. According to claim 4,
The second bent portion overlaps at least a portion of the core portion, the coil portion, and the bobbin portion in the third direction. According to claim 1,
The second bobbin,
a second top part;
a second bottom portion disposed below the second top portion; and
A second middle portion disposed between the second top portion and the second bottom portion;
The first terminal part and the second terminal part are disposed on the upper surface of the second top part of the transformer. According to claim 9,
The first bobbin,
a first top portion;
a first bottom portion disposed below the first top portion; and
A first middle portion disposed between the first top portion and the first bottom portion;
The transformer further comprises a coil lead-out portion protruding from an upper surface of the first top portion. According to claim 10,
The second bobbin further includes a hole formed in the second top portion through which the coil draw-out portion is inserted. According to claim 11,
At least a portion of the first coil is disposed in the hole. According to claim 12,
At least a part of the first coil is connected to the first terminal part via the coil take-out part. According to claim 13,
The transformer having an end of the coil lead-out portion bent toward the second direction. According to claim 2,
Wherein the first direction, the second direction and the third direction are perpendicular to each other. The transformer according to any one of claims 1 to 15; and
A circuit board on which the transformer is disposed,
The power supply unit of claim 1 , wherein a thickness of the transformer in the first direction from the upper surface of the circuit board is 14 mm or less.

Images