Transformer and flat panel display device including the same

Abstract

To provide a slim transformer which can be additionally slimmed, can secure wet inductance, and is excellent in heat dissipation performance while being slim, and to provide a flat panel display device using the same.SOLUTION: A transformer 100 according to an embodiment of the present invention includes a core part 110 including an upper core 111 and a lower core 112, a coil part partially disposed in the core part, and a bobbin part disposed between the core part and the coil part, wherein the coil part includes a primary coil and a secondary coil at least partially disposed on a side surface of the primary coil, the core part may include a first outer leg part, a second outer leg part, and a middle leg part disposed between the first outer leg part and the second outer leg part, and a shortest distance between the primary coil and the secondary coil may be 0.1 to 0.3 times a shortest distance from an outermost portion of the primary coil to one adjacent outer leg part of the first outer leg part and the second outer leg part.SELECTED DRAWING: Figure 1a

Description

[Technical Field]

[0001] The present invention relates to a transformer and a flat panel display device including the same. [Background technology]

[0002] 2. Description of the Related Art Generally, an electronic device requires a driving power source to operate, and a power supply device, for example, a power supply unit (PSU), is necessarily employed to supply the driving power to the electronic device.

[0003] In particular, display devices such as flat panel TVs are required to be slimmer as their display sizes increase, so there is a need to reduce the thickness while still meeting the increased power consumption of larger displays.

[0004] In a power supply unit (PSU), the transformer takes up a relatively large volume compared to other components, so slimming down the PSU typically involves eliminating elements that occupy a large thickness within the transformer or adjusting the quantity. For example, in the case of transformers that make up the power supply unit of a recent flat panel display device, the bobbin on which the primary and secondary coils are wound and fixed may be omitted, or multiple small-capacity slim transformers may be used.

[0005] In such PSUs, a certain range of frequencies is required due to the resonant tank design and frequency matching of the circuit. leak However, since a typical slim transformer has a structure in which the primary and secondary coils are stacked one above the other, there is a limit to how much the thickness can be reduced since both the primary and secondary coils contribute to the thickness. leak The problem is that the inductance becomes extremely low (for example, about 3 μH). leakThe inductance must be maintained at a certain level or higher for switching mode operation within the circuit.

[0006] Therefore, additional slimming is possible leak There is a demand for a transformer that can ensure inductance and a flat panel display device using the transformer. Summary of the Invention [Problem to be solved by the invention]

[0007] The technical problem that the present invention aims to achieve is to provide a device that can be further slimmed down while leak The present invention provides a slim transformer capable of ensuring inductance and a flat panel display device using the same.

[0008] Another object of the present invention is to provide a slim transformer that is slim yet has excellent heat dissipation performance, and a flat panel display device using the same.

[0009] The technical problems that the present invention aims to achieve are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which the present invention pertains from the following description. [Means for solving the problem]

[0010] According to one embodiment, a transformer includes a core portion including an upper core and a lower core, a coil portion partially disposed within the core portion, and a bobbin portion disposed between the core portion and the coil portion, wherein the coil portion includes a primary coil and a secondary coil at least partially disposed on a side of the primary coil, and the bobbin portion includes a first bobbin having a first receiving portion formed therein for receiving the primary coil, and a second bobbin having a second receiving portion formed therein for receiving the secondary coil, wherein the first bobbin includes a first extension portion extending from the first receiving portion toward the second bobbin, and the second receiving portion may be disposed on the first extension portion.

[0011] For example, the shortest distance from the lower surface of the lower core to the primary coil may be different from the shortest distance from the lower surface of the lower core to the secondary coil.

[0012] For example, it may include a first space formed between the first outer foot portion and the midfoot portion to accommodate a portion of the bobbin portion, and a second space formed between the second outer foot portion and the midfoot portion to accommodate another portion of the bobbin portion.

[0013] For example, the primary coil and the secondary coil may be at least partially overlapped in a first direction, which is a direction from the first outer leg portion to the second outer leg portion.

[0014] For example, the shortest distance between the primary coil and the secondary coil may be 0.1 to 0.3 times the shortest distance between the outermost periphery of the primary coil and an adjacent one of the first outer leg portion and the second outer leg portion.

[0015] For example, the ratio of a first distance, which is the shortest distance between the primary coil and the secondary coil outside the first space and the second space, to a second distance, which is the shortest distance between the primary coil and the secondary coil inside the first space or the second space, may be 1 to 1.3.

[0016] For example, the shortest distance from the lower surface of the lower core to the primary coil may be 0.3 to 0.7 times the shortest distance from the lower surface of the lower core to the secondary coil.

[0017] For example, the transformer may further include insulating portions disposed between the first outer leg portion and the bobbin portion in the first space and between the second outer leg portion and the bobbin portion in the second space.

[0018] 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 penetrated by the coil lead-out portion to expose the coil lead-out portion.

[0019] For example, the first bobbin may include a first top portion, a first bottom portion disposed below the top portion, and a first middle portion disposed between the top portion and the bottom portion, and the first extension portion may be disposed on the bottom portion.

[0020] 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, and the first bobbin may be at least partially received in a recess defined by a lower surface of the second top portion and an inner surface of the second middle portion.

[0021] For example, the first extension portion may face the lower surface of the second bottom portion.

[0022] In addition, according to one embodiment, a transformer includes a core portion including an upper core and a lower core, a coil portion partially disposed within the core portion, and a bobbin portion disposed between the core portion and the coil portion, wherein the coil portion includes a primary coil and a secondary coil partially disposed on a side of the primary coil, and the core portion includes a first outer leg portion, a second outer leg portion, and a middle leg portion disposed between the first outer leg portion and the second outer leg portion, and the shortest distance between the primary coil and the secondary coil may be 0.1 to 0.3 times the shortest distance from the outermost periphery of the primary coil to an adjacent one of the first outer leg portion and the second outer leg portion.

[0023] For example, the bobbin part may include a first bobbin having a first receiving portion formed therein for receiving the primary coil and a second bobbin having a second receiving portion formed therein for receiving the secondary coil, the first bobbin may include a first extension portion extending from the first receiving portion toward the second bobbin, and the second receiving portion may be disposed on the first extension portion.

[0024] For example, the shortest distance from the lower surface of the lower core to the primary coil may be different from the shortest distance from the lower surface of the lower core to the secondary coil.

[0025] For example, the shortest distance from the lower surface of the lower core to the primary coil may be shorter than the shortest distance from the lower surface of the lower core to the secondary coil.

[0026] For example, the second bobbin may include a second extension portion extending from the second receiving portion toward the first bobbin, and the first receiving portion may be disposed below the second extension portion.

[0027] For example, a portion of the second accommodating portion may be disposed between the primary coil and the secondary coil.

[0028] For example, the core portion may further include a first space formed between the first outer foot portion and the midfoot portion to accommodate a portion of the bobbin portion, and a second space formed between the second outer foot portion and the midfoot portion to accommodate another portion of the bobbin portion.

[0029] For example, the primary coil and the secondary coil may be at least partially overlapped in a first direction, which is a direction from the first outer leg portion to the second outer leg portion.

[0030] For example, the ratio of a first distance, which is the shortest distance between the primary coil and the secondary coil outside the first space and the second space, to a second distance, which is the shortest distance between the primary coil and the secondary coil inside the first space or the second space, may be 1 to 1.3.

[0031] For example, the shortest distance from the lower surface of the lower core to the primary coil may be 0.3 to 0.7 times the shortest distance from the lower surface of the lower core to the secondary coil.

[0032] For example, the coil may further include an insulating portion disposed between the first outer leg portion and the bobbin portion in the first space and between the second outer leg portion and the bobbin portion in the second space.

[0033] 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 penetrated by the coil lead-out portion to expose the coil lead-out portion.

[0034] For example, the first bobbin may include a first top portion, a first bottom portion disposed below the top portion, and a first middle portion disposed between the top portion and the bottom portion, and the first extension portion may be disposed on the bottom portion.

[0035] 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, and the first bobbin may be at least partially received in a recess defined by a lower surface of the second top portion and an inner surface of the second middle portion.

[0036] For example, the first extension portion may face a lower surface of the second bottom portion.

[0037] In addition, a flat panel display device according to one embodiment includes a power supply unit in which a transformer is disposed, the transformer including a core portion including an upper core and a lower core, a coil portion partially disposed within the core portion, and a bobbin portion disposed between the core portion and the coil portion, the coil portion including a primary coil and a secondary coil at least partially disposed on a side of the primary coil, the core portion including a first outer leg portion, a second outer leg portion, and a middle leg portion disposed between the first outer leg portion and the second outer leg, and the shortest distance between the primary coil and the secondary coil may be 0.1 to 0.3 times the shortest distance from the outermost periphery of the primary coil to an adjacent one of the first outer leg portion and the second outer leg portion.

[0038] In addition, a transformer according to another embodiment may include a core portion including an upper core and a lower core, a coil portion partially disposed within the core portion, a bobbin portion disposed between the core portion and the coil portion, and a plurality of coil fixing portions disposed to surround at least a portion of an upper portion and an outer portion of the coil portion, fixing the coil portion to the bobbin portion, and insulating it from the core portion.

[0039] For example, the coil portion may include a primary coil and a secondary coil arranged on a side of the primary coil, and the core portion may include a first outer leg portion, a second outer leg portion, and a middle leg portion arranged between the first outer leg portion and the second outer leg portion, each extending in a first direction on a plane and spaced apart from each other in a second direction intersecting the first direction.

[0040] For example, the bobbin part may include a first plate supporting the primary coil on an upper side and a first bobbin including a first sidewall disposed on an upper surface of the first plate and around which the primary coil is wound along an outer circumferential surface; and a second plate supporting the secondary coil on an upper side and a second bobbin disposed on an upper surface of the second plate and including a second sidewall disposed on the upper surface of the second plate and around which the secondary coil is wound along an outer circumferential surface, and the first bobbin may be disposed within a through hole defined by an inner circumferential surface of the second sidewall.

[0041] For example, at least some of the coil fixing portions may be disposed in portions of the upper and outer portions of the coil portion that overlap the core portion in a vertical direction.

[0042] For example, at least some of the multiple coil fixing portions may include a 1-1 coil fixing portion that extends along the first direction within a first accommodating space that is arranged between a first outer leg portion and the middle leg portion of the core portion and is arranged to surround the upper and outer surfaces of the primary coil, a 2-1 coil fixing portion that extends along the first direction within the first accommodating space and is arranged to surround the upper and outer surfaces of the secondary coil, a 1-2 coil fixing portion that extends along the first direction within a second accommodating space that is arranged between a second outer leg portion and the middle leg portion of the core portion and is arranged to surround the upper and outer surfaces of the primary coil, and a 2-2 coil fixing portion that extends along the first direction within the second accommodating space and is arranged to surround the upper and outer surfaces of the secondary coil.

[0043] For example, at least some of the multiple coil fixing portions may include a third coil fixing portion that extends along the first direction within a first accommodating space that is arranged between a first outer leg portion and the middle leg portion of the core portion and is arranged to surround the upper side of the primary coil and the upper and outer surfaces of the secondary coil, and a fourth coil fixing portion that extends along the first direction within a second accommodating space that is arranged between a second outer leg portion and the middle leg portion of the core portion and is arranged to surround the upper side of the primary coil and the upper and outer surfaces of the secondary coil.

[0044] For example, at least some of the coil fixing portions may extend from the core portion by 1 to 10 mm on both sides in the first direction.

[0045] For example, the coil fixing portions may include flexible insulating tape, and the insulating tape may include Kapton, ketone, or polyimide.

[0046] For example, the height of the bobbin portion may be set to 100% to 140% of the height of the coil portion.

[0047] For example, the thickness of each of the plurality of coil fixing portions may be within 90% of the thickness of the first plate or the second plate.

[0048] Furthermore, a flat panel display device according to another embodiment may include a power supply unit in which a transformer is disposed, and the transformer may include a core portion including an upper core and a lower core, a coil portion partially disposed within the core portion, a bobbin portion disposed between the core portion and the coil portion, and a plurality of coil fixing portions disposed to surround at least a portion of an upper and outer portion of the coil portion, fixing the coil portion to the bobbin portion and insulating it from the core portion. [Effects of the Invention]

[0049] The transformer and the flat panel display device including the same according to an embodiment of the present invention control the separation distance between the primary coil and the secondary coil, thereby leak Ensure inductance.

[0050] In addition, the coupling structure between the first and second bobbins ensures an insulating distance between the primary coil and the core. leak Inductance can be ensured.

[0051] In addition, in the transformer and flat panel display device including the same according to other embodiments, the upper part of the bobbin part is replaced with a thin-film type coil fixing part, so it can be made slimmer than a general bobbin including an upper plate.

[0052] Furthermore, not only is it not easy to dissipate heat through the portion above the bobbin where the coil fixing portion is not located, but even the portion where the coil fixing portion is located is more advantageous for heat dissipation than a typical bobbin that includes an upper plate.

[0053] The effects obtained by the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those having ordinary skill in the art to which the present invention pertains from the following description. [Brief explanation of the drawings]

[0054] [Figure 1a] FIG. 1 is a perspective view of a transformer according to one embodiment. [Figure 1b] FIG. 2 is a plan view of a transformer according to one embodiment. [Figure 2] FIG. 1 is an exploded perspective view of a transformer according to an embodiment. [Figure 3] FIG. 2 is an exploded perspective view of a bobbin portion according to an embodiment. [Figure 4a] 1B is a cross-sectional view of the transformer according to the embodiment taken along line BB' in FIG. 1B. [Figure 4b] FIG. 4(b) is a partially enlarged view of FIG. [Figure 5a] 1B is a cross-sectional view of the transformer according to the embodiment taken along line AA' in FIG. 1B. [Figure 5b] This is an enlarged view of part 'C' in FIG. 5a. [Figure 6] FIG. 2 is a diagram illustrating an example of a circuit configuration of a power supply unit of an electronic product. [Figure 7] FIG. 10 is a diagram illustrating a ratio of leakage inductance depending on a winding separation ratio of a transformer according to an embodiment. [Figure 8]FIG. 10 is a cross-sectional view of a transformer according to another aspect of an embodiment. [Figure 9] FIG. 10 is a perspective view of a transformer according to another embodiment. [Figure 10] FIG. 10 is an exploded perspective view of a transformer according to another embodiment. [Figure 11] FIG. 10 is a perspective view showing a state in which a core is removed from a transformer according to another embodiment. [Figure 12] FIG. 10 is a plan view of a transformer according to another embodiment. [Figure 13] 13 is a cross-sectional view of a transformer according to another embodiment taken along line DD' in FIG. 12. FIG. [Figure 14] 10A to 10C are diagrams illustrating an example of an assembly process for a transformer according to another embodiment. [Figure 15] 10A to 10C are diagrams showing an example of an assembly process for a transformer according to another aspect of another embodiment. [Figure 16] FIG. 10 is a cross-sectional view of a transformer according to another aspect of another embodiment. [Figure 17] FIG. 10 is a cross-sectional view of a transformer according to a comparative example. [Figure 18] FIG. 10 is a diagram showing the results of a heat generation test for a comparative example of a transformer according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0055] Although the present invention can be modified in various ways and can have various embodiments, specific embodiments will be described with reference to the drawings. However, it should be understood that this is not intended to limit the present invention to the specific embodiments, and that the present invention includes all modifications, equivalents, and alternatives that fall within the spirit and technical scope of the present invention.

[0056] Terms including ordinal numbers such as "first," "second," etc. may be used to describe various elements, but the elements are not limited by these terms. These terms are used solely to distinguish one element from another. For example, a second element may be referred to as a first element, and similarly, a first element may be referred to as a second element, without departing from the scope of the present invention. The term "and / or" includes a combination of multiple related listed items or any of multiple related listed items.

[0057] 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 be additional components in between. On the other hand, when a component is said to be "directly coupled" or "directly connected" to another component, it should be understood that there are no additional components in between.

[0058] In the description of the embodiments, when a layer (film), region, pattern, or structure is described as being "on" or "under" a substrate, layer (film), region, pad, or pattern, this includes those formed directly or with other layers interposed therebetween. The reference to "on" or "under" each layer is based on the drawings. In addition, the thickness and size of each layer (film), region, pattern, or structure in the drawings may be modified for clarity and convenience of description and do not necessarily reflect the actual size.

[0059] 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.

[0060] Unless otherwise defined, 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 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.

[0061] In the following detailed description of the embodiments with reference to the accompanying drawings, the same or corresponding components will be given the same reference numerals regardless of the drawing numbers, and redundant description thereof will be omitted. Furthermore, although the embodiments are described using a Cartesian coordinate system, it goes without saying that other coordinate systems can be used for the description. In the Cartesian coordinate system, the x-axis, y-axis, and z-axis shown in each drawing are orthogonal to each other, but the embodiments are not limited to this. The x-axis, y-axis, and z-axis can also intersect each other.

[0062] Furthermore, considering that the transformer according to the embodiment is implemented in a display device, the thickness (vertical height) of the transformer, which contributes to slimming down the display device, can be 14 mm or less, preferably 12 mm or less, and more preferably 10 mm or less.

[0063] The transformer according to this embodiment will be described in detail below with reference to the accompanying drawings.

[0064] Figure 1a shows a perspective view of a transformer according to an embodiment, Figure 1b shows a plan view of the transformer according to an embodiment, Figure 2 shows an exploded perspective view of the transformer according to an embodiment, and Figure 3 shows an exploded perspective view of a bobbin part according to an embodiment.

[0065] 1a to 3, a transformer 100 according to an embodiment includes a core portion 110, bobbin portions 120 and 130, and terminal portions TM1 and TM2. Each component will be described in detail below.

[0066] The core units 111 and 112 have magnetic circuit characteristics and can function as a magnetic flux path. The core units 111 and 112 may include an upper core 111 joined at the top and a lower core 112 joined at the bottom. The two cores 111 and 112 may be vertically symmetrical or asymmetrical to each other. However, for the sake of convenience, the following disclosure will be assumed to be vertically symmetrical.

[0067] Each of the upper core 111 and the lower core 112 may include a flat body portion and a plurality of leg portions OL1-1, OL1-2, OL2-1, OL2-2, CL1, and CL2 that protrude from the body portion in the thickness direction (i.e., the Z-axis direction) and extend along a predetermined direction. For example, the plurality of leg portions OL1-1, OL1-2, and CL1 of the upper core 111 may extend along one axis (here, the Y-axis) on a plane and include two outer legs OL1-1 and OL1-2 that are spaced apart from each other along the other axis (here, the X-axis), and one middle leg CL1 that is located between the two outer legs OL1-1 and OL1-2.

[0068] When the upper core 111 and the lower core 112 are joined together, the outer legs OL1-1, OL1-2 and the middle leg CL1 of the upper core 111 face the corresponding outer legs OL2-1, OL2-2 and the middle leg CL2 of the lower core 112. The outer leg pair OL1-1, OL2-1 on one side facing each other can be called a first outer leg portion, the outer leg pair OL1-2, OL2-2 on the other side can be called a second outer leg portion, and the middle leg pair CL1, CL2 can be called a middle leg portion.

[0069] A gap of a predetermined distance (for example, 10 to 200 μm, but not limited thereto) may be formed between at least some of the opposing outer leg pairs and middle leg pairs. The inductance of the core part 110 can be controlled by adjusting the size of the gap between one middle leg pair and two outer leg pairs, and heat generation can be controlled by adjusting the number of gaps.

[0070] Additionally, the core portion 110 may include a magnetic material such as, but not limited to, iron or ferrite.

[0071] Since the core portion 110 surrounds a portion of the outside of the bobbin portions 120 and 130, it can be seen that a portion of the primary coil (not shown) and secondary coil (not shown) housed in the bobbin portions 120 and 130 are disposed within the core portion 110.

[0072] The bobbin section 120, 130 may include a first bobbin 120 and a second bobbin 130.

[0073] The first bobbin 120 and the second bobbin 130 have a first through hole TH1 and a second through hole TH2, respectively, and may be aligned so that the middle leg portions CL1 and CL2 of the core portion 110 pass through the first through hole TH1 and the second through hole TH2.

[0074] The first bobbin 120 may be at least partially housed within the second bobbin 130 and may include a first top portion 121 , a first middle portion 123 , and a first bottom portion 122 .

[0075] The first top part 121 and the first bottom part 122 may each have a rectangular planar shape with rounded corners, but are not limited thereto. In addition, the first bottom part 122 may have a planar shape that extends outward from the first top part 121 in the direction in which the leg parts are spaced apart (i.e., the X-axis direction).

[0076] The first middle part 123 is disposed vertically between the first top part 121 and the first bottom part 122 and can insulate the conductive wire (not shown) constituting the primary coil from the mid-leg part. A space defined by the lower surface of the first top part 121, the outer surface of the first middle part 122, and a part of the upper surface of the first bottom part can function as an accommodation space for accommodating the conductive wire constituting the primary coil.

[0077] 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.

[0078] The second middle part 133 is disposed vertically between the second top part 131 and the second bottom part 132 and can insulate the conductive wire (not shown) constituting the secondary coil from the conductive wire (not shown) constituting the primary coil. A space defined by a portion of the lower surface of the second top part 131, the outer surface of the second middle part 132, and a portion of the upper surface of the second bottom part can function as an accommodation space for accommodating the conductive wire constituting the secondary coil.

[0079] In addition, the board support portions CBS1 and CBS2 spaced apart from each other in the longitudinal direction of the second bottom portion 132 can function to support the transformer 100 when mounted on a circuit board (not shown) of a device such as a PSU.

[0080] Terminal portions TM1 and TM2 may be disposed on both ends of the second top portion 132 in the longitudinal direction. The terminal portions TM1 and TM2 may function to fix the transformer 100 to a board (not shown) of a power supply unit (PSU) and to function as electrical connection paths between the primary coil and secondary coil (not shown) of the transformer 100 and the board (not shown) of the power supply unit (PSU).

[0081] More specifically, the first terminal portion TM1 may include a plurality of pins spaced apart from one another, at least some of which may be electrically connected to one of the ends of a conductive wire constituting the primary coil, and the second terminal portion TM2 may include a plurality of pins spaced apart from one another, at least some of which may be electrically connected to one of the ends of a conductive wire constituting the secondary coil.

[0082] When the transformer 100 is constructed, at least a portion of the first bobbin 120 may be received in a recess RC defined by the lower surface of the second top portion 131 and the inner surface of the second middle portion 133 of the second bobbin 130. When the first bobbin 120 and the second bobbin 130 are coupled together, the upper surface of the first top portion 121 faces the lower surface of the second top portion 131, and a portion of the upper surface of the first bottom portion 122 that does not vertically overlap with the first top portion 121 (i.e., the 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 be exposed upward through the third through-hole TH3 of the second top portion 131 in the coupled state. The coil lead-out portion 124 allows both ends of the conductive wire constituting the primary coil to be easily led out and fixed to the upper surface of the second top portion 131 and immediately connected to the first terminal portion TM1.

[0083] The respective accommodation states of the primary coil and the secondary coil according to the coupling structure of the bobbin parts 120 and 130 are as follows: Figure 4a 5b.

[0084] Figure 4a 1B is a cross-sectional view of the transformer according to the embodiment taken along line BB' in FIG. 1B. FIG. 4b is a partially enlarged view of FIG. 4(a).

[0085] Figure 4a, Figure 4b 1, the bobbin portions 120 and 130 are disposed between the core portion 110 and the coil portions 140 and 150.

[0086] More specifically, the coil units 140, 150 and the bobbin units 120, 130 are partially disposed across the first space SP1 and the second space SP2 within the core unit 110. The first space SP1 and the second space SP2 may be spaced apart from each other along the direction in which the leg units are spaced apart (i.e., the X-axis direction) across the midfoot units CL1, CL2, respectively, and have a rectangular cross-sectional shape extending along the Y-axis direction. The first space SP1 may be located between the midfoot units CL1, CL2 and the outer leg units OL1-1, OL2-1 of the core unit 110, and the second space SP2 may be located between the midfoot units CL1, CL2 and the outer leg units OL1-2, OL2-2 of the other side.

[0087] The first bobbin 120 may include a first receiving portion RP1 that receives the primary coil 140, and a first extension portion EP1 that extends from the first receiving portion RP1 toward the second bobbin 130. That is, the first receiving portion RP1 may correspond to the first top portion 121, the first middle portion 123, and the first bottom portion 122 excluding the first extension portion EP1.

[0088] The second bobbin 130 may include a second housing portion RP2 that houses the secondary coil 150, and a second extension portion EP2 that extends from the second housing portion RP2 toward the first bobbin 120. That is, the second housing portion RP2 may include a portion of the second top portion 131 excluding the second extension portion EP2, a second middle portion 133, and a second bottom portion 132.

[0089] Furthermore, the second housing portion RP2 is disposed on the first extension portion EP1, and the first housing portion RP1 is disposed below the second extension portion EP2. Therefore, 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 shorter 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 from the lower surface of the lower core 112 to the primary coil 140 may be 0.3 to 0.7 times the shortest distance h2 from the lower surface of the lower core 112 to the secondary coil 150.

[0090] Furthermore, due to the coupling structure of the bobbin parts 120 and 130, the primary coil 140 and the secondary coil 150 only partially overlap in the direction from one outer leg to the other, and the remaining portions do not overlap. In the vertical direction, the primary coil 140 and the secondary coil 150 may not overlap each other.

[0091] At least a part of the secondary coil 150 is disposed on the side of the primary coil 140, and a part of the second housing portion RP2, that is, the second middle portion 133, is disposed between the primary coil 140 and the secondary coil 150 in the horizontal direction.

[0092] Each of the primary coil 140 and the secondary coil 150 may be a multi-winding of a rigid conductor metal, such as a copper conductive wire, wound several times, but is not necessarily limited to this. 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 to this.

[0093] Meanwhile, insulating portions 161 and 162 may be disposed between the bobbin portions 120 and 130 and both outer legs, respectively. The insulating portions 161 and 162 may extend outward from the upper surface of the second receiving portion RP2, bend, further extend to surround the outer sides of the second receiving portion RP2 and the first extension portion EP1, and further be bent and extend toward the lower surface of the first extension portion EP1. This allows both the secondary coil 150 and the primary coil 140 to be insulated from the outer legs of the core portion 110. The insulating portions 161 and 162 may include, but are not limited to, a component with excellent insulating properties, such as ketone or polyimide.

[0094] The above-described structure significantly increases the insulation distance of primary coil 140 from core portion 110. For example, without second extension EP2, first insulation distance PATH1 to the upper side of primary coil 140 would immediately reach the bottom surface of the upper bobbin. However, the presence of second extension EP2 extends it by at least the length of the second extension in the x-axis direction. Also, second insulation distance PATH2 to the lower side of primary coil 140 can be extended by the length of first extension EP1 in the x-axis direction and the length of insulating portions 161 and 162 in the same direction.

[0095] Also, the distance β between the primary coil 140 and the secondary coil 150 is simply ensured. leak In addition to the inductance, the horizontal displacement of the first housing portion RP1 and the second housing portion RP2 causes an additional leak Inductance can be ensured.

[0096] Below, a cross section of the portion not surrounded by the core portion 110 will be described with reference to FIGS. 5a and 5b.

[0097] FIG. 5a is a cross-sectional view of a transformer according to an embodiment taken along line AA' in FIG. 1b, and FIG. 5b is an enlarged view of part 'C' in FIG. 5a.

[0098] 5a and 5b together, the first extension portion EP1 may not be disposed on the first bobbin 120 in a portion where the bobbin parts 120 and 130 are not surrounded by the core part 110. In addition, the shortest distance α between the primary coil 140 and the secondary coil 150 in a portion where the bobbin parts 120 and 130 are not surrounded by the core part 110, i.e., outside the first space SP1 and the second space SP2, may be the same as or different from the shortest distance β between the primary coil 140 and the secondary coil 150 in a portion where the bobbin parts 120 and 130 are surrounded by the core part 110.

[0099] Preferably, the ratio of the shortest distances (β / α) can be 1 to 1.3. If the ratio of the shortest distances (β / α) is less than 1, it will cause an increase in the overall size of the transformer 100, leak The change in inductance is not significant. Conversely, if the ratio of the shortest distances (β / α) exceeds 1.3, the energy conversion efficiency of the transformer 100 decreases. However, this range corresponds to when the A-A' and B-B' cross sections in FIG. 1b intersect at the center of the midfoot portion on a plane, and the ratio of the shortest distances (β / α) can vary depending on the radius of curvature of the first middle portion 123 and the second middle portion 133 in the winding direction.

[0100] The transformer 100 according to the embodiment will be described below with reference to FIG. 6 together with the circuit configuration in which the transformer 100 is implemented.

[0101] FIG. 6 shows an example of the circuit configuration of the power supply section of an electronic product. Referring to FIG. 6, the circuit configuration of a power supply unit (i.e., PSU) for an electronic product, such as a flat-panel TV, is shown, including a square wave generating unit 210, a resonating unit 220, and a rectifying unit 230. Flat-panel TVs generally support other operating modes, such as a low-power mode, in addition to a normal mode. Since high efficiency is required for each operating mode, the resonating unit 220 is implemented as an LLC resonant converter. The LLC resonant converter includes a first inductor (Lr) 221, a second inductor (Lm) 222, and a capacitor (Cr) 223. The inductance Lm of the second inductor 222 can be considered the inductance that operates the circuit. The resonant frequency varies depending on the operating frequency of the PSU. Factors that determine 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 are not set to appropriate values, the efficiency of the entire circuit may decrease or the circuit may not operate normally.

[0102] Transformer 100 according to the embodiment leak The value of inductance L of the inductance-integrated transformer corresponds to Lm in the resonating unit 220, leak The value of the inductance Lk corresponds to Lr.

[0103] The Lk / Lm ratio required for a typical flat panel TV PSU is at the 10-20% level, but conventional transformers have a very low Lk value, making it difficult to meet this requirement.

[0104] More specifically, the Transformers leak Inductance can be calculated using the following formula 1.

[0105]

number

[0106] In Equation 1, Lk is leakwhere k is the inductance, Lm is the inductance of the transformer, and k is the coupling coefficient. The coupling coefficient (k) can be determined experimentally. For example, it can be calculated using the following equation (2).

[0107]

number

[0108] In Equation 2, x is the winding spacing ratio, which means the ratio of the spacing between the primary coil and the secondary coil to the shortest distance between the outer legs adjacent to the outermost periphery of the primary coil, which defines the space in which the secondary coil can be wound (hereinafter referred to as the "winding space" for convenience).

[0109] More specifically, when both the first bobbin 120 and the second bobbin 130 are present, the shortest distance between the primary coil 140 and the secondary coil 150 (i.e., β in FIG. 4) corresponds to the distance between the outermost periphery of the primary coil 140 and the innermost periphery of the secondary coil 150. Also, assuming that only the first bobbin 120 is present, the maximum distance that the secondary coil 150 can form with the primary coil 140 within the winding space where it can exist is the shortest distance from the outermost periphery of the primary coil 140 to the adjacent outer leg (i.e., d1 in FIG. 4).

[0110] Transformers leak The inductance varies depending on the coupling coefficient, which is particularly affected by the shortest distance between the primary coil 140 and the secondary coil 150 inside the core portion 110 .

[0111] However, the shortest distance β between the primary coil 140 and the secondary coil 150 is determined by where the innermost periphery of the secondary coil 150 is located within the winding space. If only the increase in the shortest distance β is considered, when the winding space is fixed, the number of turns of the secondary coil 150 is limited, and in order to increase the winding space, the core part 110 must be enlarged, making it difficult to approach this from the perspective of expanding the winding space.

[0112] 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 periphery of the primary coil 140 to the adjacent outer leg is controlled, i.e., the winding gap ratio is controlled. leak Ensure inductance.

[0113] FIG. 7 and Table 1 below show the results of experiments using the shortest distance β between the primary coil 140 and the secondary coil 150 and the winding separation ratio. leak The change in inductance is shown. In the experiment, the primary coil 140 was a 0.1Ψ*40 double-layer winding, using a conductive wire with a thickness of 0.75 mm, and the secondary coil 150 was a 0.08Ψ*210 double-layer winding, using a conductive wire with a thickness of 1.4 mm.

[0114] [Table 1]

[0115] figure 8 The horizontal axis represents the gap ratio, and the vertical axis represents the self-inductance Lm of the transformer 100. leak Ratio of inductance LL (L L The ratios are shown in the figure. 8 1, the larger the gap ratio, the greater the self-inductance Lm of the transformer 100. leak Inductance L L It can be seen that the ratio of increases in the form of a logarithm (e.g., can be modeled as y=0.0556ln(x)+0.2693 with a 0.997 proximity).

[0116] However, it is preferable that the shortest distance β between the primary coil 140 and the secondary coil 150 is 0.1 to 0.3 times d1. This is because if the ratio is less than 0.1, the LLC matching of the circuit (e.g., PSU) board on which the transformer is mounted may be misaligned, causing the operating frequency to increase and making the board uncontrollable. If the ratio exceeds 0.3, the efficiency of the transformer 100 may decrease, causing oscillation on the board. However, this is an example assuming a general PSU, and the mounted circuit may not necessarily be limited to this.

[0117] Finally, referring to Equation 1 and Equation 2, leak The inductance is affected by the coupling coefficient (k), which is affected by the distance and overlap area between the primary coil and the secondary coil. leak In order to increase the inductance, the distance between the primary coil and the secondary coil is controlled to reduce the coupling coefficient, and the primary coil accommodation space and the secondary coil accommodation space are horizontally offset. leak Additional inductance was provided.

[0118] Therefore, the transformer according to the embodiment is slim and yet can secure a high Lk value due to the bobbin part coupling structure described above, and is therefore suitable for configuring a power supply part for a flat panel TV.

[0119] In the transformer 100 according to the embodiment described above, the second receiving portion RP2 is disposed above the first extension portion EP1 and the first receiving portion RP1 is disposed below the second extension portion EP2 in at least the portion surrounded by the core portion 110 due to the coupling structure of the bobbin portions 120 and 130. This means that the first receiving portion RP1 and the second receiving portion RP2 do not overlap at least partially in the horizontal direction. However, according to another aspect of the embodiment, the space in which the primary coil 140 is accommodated and the space in which the secondary coil 150 is accommodated may be parallel to each other. This will be described with reference to FIG. 8.

[0120] figure7 1 is a cross-sectional view of a transformer according to another aspect of an embodiment.

[0121] figure 7 1 shows a cross-sectional view of a portion of a transformer 100′ in which a primary coil 140, a secondary coil 150, a first bobbin 120′, and a second bobbin 130′ are surrounded by a core portion 110. 7 For clarity, the insulating portions 161 and 162 are not shown in the drawings. However, it goes without saying that the transformer 100 ′ according to other embodiments may also include the insulating portions 161 and 162 .

[0122] The first bobbin 120 ′ provides a first receiving space RS 1 for receiving the primary coil 140 , and the second bobbin 130 ′ provides a second receiving space RS 2 for receiving the secondary coil 150 .

[0123] The second bobbin 130' can be disposed outside the first bobbin 120' between the midfoot portions CL1, CL2 and the first outer foot portions OL1-1, OL1-2 and between the midfoot portions CL1, CL2 and the second outer foot portions OL2-1, OL2-2.

[0124] Furthermore, the first housing space RS1 and the second housing space RS2 may at least partially overlap in the direction from the first outer leg portions OL1-1, OL1-2 to the second outer leg portions OL2-1, OL2-2 of the core part 110. For example, the first housing space RS1 and the second housing space RS2 may be parallel to each other, but this is not necessarily limited to this.

[0125] The overlap of the accommodation spaces RS1 and RS2 allows at least a portion of the primary coil 140 and the secondary coil 150 to overlap in the direction from the first outer leg portions OL1-1 and OL1-2 to the second outer leg portions OL2-1 and OL2-2.

[0126] Preferably, in the transformer 100′ according to another embodiment, the winding spacing ratio, i.e., the ratio (β′ / d2) of the shortest distance β′ between the primary coil 140 and the secondary coil 150 to the shortest distance d2 from the outermost periphery of the primary coil 140 to the adjacent outer leg portion, can be 0.1 to 0.3.

[0127] Furthermore, similar to the transformer 100 of the embodiment, in the transformer 100′ according to another aspect, the shortest distance between the primary coil 140 and the secondary coil 150 in the portion of the bobbin portions 120′, 130′ that is not surrounded by the core portion 110 may be the same as or different from the shortest distance β′ between the primary coil 140 and the secondary coil 150 in the portion of the bobbin portions 120′, 130′ that is surrounded by the core portion 110. Preferably, the ratio of the shortest distances (β / α) may be 1 to 1.3.

[0128] Hereinafter, the transformers 300 and 300' according to other embodiments will be described in detail with reference to the accompanying drawings.

[0129] FIG. 9 is a perspective view of a transformer according to another embodiment, and FIG. 10 is an exploded perspective view of a transformer according to another embodiment.

[0130] 9 and 10 , a transformer 300 according to another embodiment may include a core unit 310, bobbin units 320 and 330, a primary coil 340, a secondary coil 350, primary coil fixing units 361, 362, 363 and 364, and secondary coil fixing units 371, 372, 373 and 374. Each component will be described in detail below.

[0131] The core units 311 and 312 have a similar configuration to the core units 111 and 112 described above in the first embodiment, and therefore a duplicated description will be omitted.

[0132] In another embodiment, when the upper core 311 and the lower core 312 are joined vertically, a first accommodating space may be arranged between the first outer foot part and the middle foot part, and a second accommodating space may be arranged between the second outer foot part and the middle foot part.

[0133] The bobbin section 320 , 330 may include a first bobbin 320 and a second bobbin 330 .

[0134] The first bobbin 320 and the second bobbin 330 each have a first through hole TH1 and a second through hole TH2, and the mid-leg portions CL1 and CL2 of the core portion 310 can be aligned so as to pass through the first through hole TH1 and the first bobbin 120 can be accommodated within the second through hole TH2.

[0135] Each of the first bobbin 320 and the second bobbin 330 may have a major axis extending in the direction in which the midfoot portion and the outer foot portion extend on a plane (i.e., the Y-axis direction), and a minor axis extending in the direction in which the midfoot portion and the outer foot portion move away from each other on a plane (i.e., the X-axis direction).

[0136] 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 .

[0137] The first side wall 321 may have a rectangular planar shape with rounded corners, and the first plate 322 may have a rectangular ring planar shape with rounded corners, but the shapes are not necessarily limited thereto.

[0138] The first side wall 321 may insulate the middle legs CL1 and CL2 from the primary coil 340. The inner circumferential surface of the first side wall 321 defines a first through hole TH1, and the primary coil 340 may be wound along the outer circumferential surface.

[0139] The first plate 322 can insulate the lower core 322 from the primary coil 340 and can support the primary coil 340 on the upper side.

[0140] 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 .

[0141] The second side wall 331 may have a rectangular planar shape with rounded corners, and the second plate 332 may have a rectangular ring planar shape with rounded corners, but the shapes are not necessarily limited thereto.

[0142] The second side wall 331 can insulate the primary coil 340 from the secondary coil 350 . In addition, the inner circumferential surface of the second side wall 331 defines a second through-hole TH2, and the outer circumferential surface thereof can have a secondary coil 350 wound therearound.

[0143] The second plate 332 can insulate the lower core 322 from the secondary coil 350 and can support the secondary coil 350 on its upper side.

[0144] Each of the primary coil 340 and the secondary coil 350 may be a multi-winding of a rigid conductor metal, such as a copper conductive wire, wound several times, but is not necessarily limited thereto. The thickness of the conductive wire constituting the secondary coil 350 may be 50% to 150% of the thickness of the conductive wire constituting the primary coil 340, but is not necessarily limited thereto. In the transformer 300 according to the embodiment, the primary coil 340 may correspond to the primary coil, and the secondary coil 150 may correspond to the secondary coil, but is not necessarily limited thereto. Both ends of the conductive wire constituting the primary coil 340 and both ends of the conductive wire constituting the secondary coil 350 may be drawn in directions opposite to each other, but this drawing direction is merely an example and is not necessarily limited thereto.

[0145] Meanwhile, coil fixing portions 361, 362, 363, 364, 371, 372, 373, and 374 may be disposed on at least a portion of the upper portion and outer circumferential surface of each of the primary coil 140 and the secondary coil 350. The coil fixing portions 361, 362, 363, 364, 371, 372, 373, and 374 may include a material having insulating properties and flexibility. For example, the coil fixing portions may include insulating tape made of Kapton, ketone, polyimide, and the like. As another example, the coil fixing portions may be made of polymer molding or adhesive bonding, such as epoxy. However, the present invention is not limited thereto as long as the coil fixing portions can fix the primary coil 340 and the secondary coil 350 and insulate them from at least the core portion 310.

[0146] The coil fixing portion may include primary coil fixing portions 361, 362, 363, and 364 and secondary coil fixing portions 371, 372, 373, and 374.

[0147] The primary coil fixing parts 361, 362, 363, and 364 are disposed on at least a part of the upper surface and outer circumferential surface (or upper and outer parts) of the primary coil 340, and can fix and insulate the primary coil 340.

[0148] In addition, the secondary coil fixing parts 371, 372, 373, and 374 are disposed on at least a part of the upper surface and outer circumferential surface (or upper and outer parts) of the secondary coil 350, thereby fixing and insulating the secondary coil 350.

[0149] The coil fixing portion will be described in more detail below with reference to Figures 11 to 13. Figure 11 is a perspective view showing a state in which the core has been removed from a transformer according to another embodiment.

[0150] Referring to FIG. 11, the primary coil fixing portions 361, 362, 363, and 364 may include a 1-1 coil fixing portion 361 and a 1-2 coil fixing portion 362 that extend along the major axis direction (i.e., the Y-axis direction) of the first bobbin 320 and face each other, and a 1-3 coil fixing portion 363 and a 1-4 coil fixing portion 364 that extend along the minor axis direction (i.e., the X-axis direction) of the first bobbin 320 and face each other.

[0151] In addition, the secondary coil fixing portions 371, 372, 373, and 374 may include a 2-1 coil fixing portion 371 and a 2-2 coil fixing portion 372 that extend along the long axis direction (i.e., the Y-axis direction) of the second bobbin 330 and face each other, and a 2-3 coil fixing portion 373 and a 2-4 coil fixing portion 374 that extend along the short axis direction (i.e., the X-axis direction) of the second bobbin 330 and face each other.

[0152] FIG. 12 is a plan view of a transformer according to another embodiment, and FIG. 13 is a cross-sectional view of the transformer according to another embodiment taken along line DD' in FIG.

[0153] For ease of understanding, the plan view shown in Fig. 12 illustrates a shape of a transformer 300 according to another embodiment with the upper core 311 removed. Referring to Fig. 12, in order to ensure insulation with respect to the core unit 310, it is preferable that each of the 1-1 coil fixing portion 361, the 2-1 coil fixing portion 371, the 1-2 coil fixing portion 362, and the 2-2 coil fixing portion 372 extend from the core unit 310 in the extension direction (i.e., the Y-axis) by a certain length d4. For example, d4 may be 1 mm to 10 mm, but is not necessarily limited thereto.

[0154] Meanwhile, the lengths of the coil fixing portions 363, 364, 373, and 374 in the extension direction (i.e., the X-axis direction) extending along the minor axis direction (i.e., the X-axis) of the first bobbin 320 and the second bobbin 330 may be determined depending on the width of the corresponding coil. For example, the length d5 ​​of the second-third coil fixing portion 373 in the extension direction may be 1 / 5 to 1 / 3 of the width d6 of the secondary coil 150 in the corresponding direction. This is because if the ratio of d5 / d6 is less than 1 / 5, the fixing of the coil becomes weak, and if it exceeds 1 / 3, the area covered by the coil fixing portion increases, hindering heat dissipation. However, it will be apparent to those skilled in the art that the above ratios are merely examples and may be changed within a range that ensures heat dissipation performance and fixation.

[0155] 11 and 12 are merely examples and are not necessarily limited thereto. For example, the first-third coil fixing portion 363, the second-third coil fixing portion 373, the first-fourth coil fixing portion 364, and the second-fourth coil fixing portion 374 are disposed at the center of the minor axis direction of each of the first bobbin 320 and the second bobbin 330, but at least some of the coil fixing portions 363, 364, 373, and 374 may be divided into two or more portions and disposed spaced apart from each other along the minor axis direction.

[0156] However, it is preferable that coil fixing parts be disposed at the portions of the primary coil 340 and secondary coil 350 that vertically overlap the core part 310 so that the primary coil 340 and secondary coil 350 can be insulated from the core part 110. This will be explained with reference to Fig. 13 .

[0157] Referring to Figure 13, it is preferable to always provide a 1-1 coil fixing portion 361 and a 2-1 coil fixing portion 371 arranged in the first storage space between the first outer leg portions OL1-1, OL2-1 and the middle leg portions CL1, CL2, and a 1-2 coil fixing portion 362 and a 2-2 coil fixing portion 372 arranged in the second storage space between the second outer leg portions OL1-2, OL2-2 and the middle leg portions CL1, CL2.

[0158] Meanwhile, the thickness of each of coil fixing portions 361, 362, 363, 364, 371, 372, 373, and 374 may be 90% or less of the thickness t of first plate 322 or second plate 332. Furthermore, height h3 of bobbin portions 320 and 330 may be the same as height h4 of primary coil 340 or secondary coil 350, or may be 140% or less of height h4. For example, if height h4 of coils 340 and 350 is 1.8 cm, the height of the bobbin may be 1.8 to 2.52 cm.

[0159] FIG. 14 shows an example of an assembly process for a transformer according to another embodiment.

[0160] 14 shows an arrangement of the 2-2 coil fixing part 372. Specifically, the 2-2 coil fixing part 372 may be attached from the upper surface of the second side wall 331 of the second bobbin 130, sequentially over the upper and outer surfaces of the secondary coil 350, and sequentially surrounding the side surface of the second plate 331. The attachment order may be different from that shown in FIG. 14, and for stronger fixation and insulation, the 2-2 coil fixing part 372 may extend from the upper surface of the second side wall 331 to at least a portion of the inner surface of the second side wall, or may extend from the side surface of the second plate 332 to at least a portion of the bottom surface.

[0161] According to another aspect of the other embodiment, one coil fixing portion can fix and insulate the primary coil 340 and the secondary coil 350 together, as will be explained with reference to FIGS.

[0162] FIG. 15 shows an example of an assembly process for a transformer according to another aspect of the other embodiment, and FIG. 16 is a cross-sectional view of a transformer 300' according to another aspect of the other embodiment.

[0163] 15 and 16 , when the bobbin parts 320, 330, primary coil 340, and secondary coil 350 are assembled, one coil fixing part 382 may be attached from the upper surface of the first side wall 321 of the second bobbin 330 to the upper surface of the primary coil 340, the upper surface of the second side wall 331, the upper surface of the secondary coil 350, and the outer peripheral surface of the secondary coil 350, in that order, to surround the side surface of the second plate 331. The attachment order may be different from that shown in FIG. 15 , and for stronger fixation and insulation, the coil fixing part 382 may extend from the upper surface of the first side wall 331 to at least a portion of the inner peripheral surface of the first side wall, or from the side surface of the second plate 332 to at least a portion of the bottom surface.

[0164] 15, the method of fixing the primary coil 340 and the secondary coil 350 together by one coil fixing part can be applied to the positions of the coil fixing part 382 and the bobbin parts 320 and 330 facing each other in the minor axis direction (i.e., positions 361 and 371), and to two major axis end positions facing each other in the major axis direction (i.e., positions 363, 373 and 364, 374) of the bobbin parts 320 and 330. For example, FIG. 16 shows an example in which one coil fixing part 381 is disposed at the positions of the coil fixing part 382 and the bobbin parts 320 and 330 facing each other in the minor axis direction (i.e., positions 361 and 371) shown in FIG.

[0165] Hereinafter, the effects of the transformers 300 and 300' according to other embodiments will be described in comparison with a transformer 300'' according to a comparative example with reference to FIGS. 17 and 18.

[0166] FIG. 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 other embodiments, at least a portion of the upper surfaces of the primary coil 340 and secondary coil 350 are fixed and insulated by coil fixing parts 361, 362, 363, 364, 371, 372, 373, 374, 381, and 382, ​​whereas in the transformer 300″ according to the comparative example, an upper plate 333″ is disposed on the bobbin parts 320″ and 330″, so that the primary coil 340 and secondary coil 350 are fixed and insulated.

[0167] In this case, assuming that the primary coil 340 and secondary coil 350 of the comparative example transformer 300″ have the same configuration and internal storage space as the transformer 300 according to the other embodiments, the size of the comparative example transformer 300″ will have to be larger.

[0168] For example, suppose the sizes of the space RS1 for accommodating the primary coil 340 and the space RS2 for accommodating the secondary coil 350 in FIG. 13 are the same as the sizes of the space RS1″ for accommodating the primary coil 340 and the space RS2″ for accommodating the secondary coil 350 in FIG. 17, respectively, and the thickness of the upper plate 333″ is the same as the thickness t of the first plate 322 and the second plate 332. In this case, in order to ensure the same sizes of accommodation spaces RS1 and RS2, in the transformer 300 according to another embodiment, a minimum height of the accommodation space within the core unit 310 corresponding to the sum of the height h3 of the bobbin units 320 and 330 and the thickness of the coil fixing unit in the vertical direction is required. On the other hand, in the transformer 300″ according to the comparative example, in order to ensure the same sizes of accommodation spaces RS1″ and RS″, a minimum height of the accommodation space within the core unit 310″ of only h3+t is required.

[0169] In other words, the height of the accommodation space required within core part 310 of transformer 300 according to the other embodiment is lower than the height of the accommodation space required within core part 310" of transformer 300" according to the comparative example by "t - thickness of core fixing part." Here, because the thickness of the core fixing part is less than 90% of t as described above, the height of transformer 300 according to the other embodiment can be reduced by at least 0.1t compared to the comparative example, allowing for further slimming.

[0170] Furthermore, the upper plates (eg, 333") of the bobbin parts 320" and 330" according to the comparative example are integrally formed with the remaining parts of the bobbin parts, and are therefore made of the same hard polymer resin. Therefore, since it is difficult to flexibly change the accommodation spaces RS1" and RS2" of the primary coil 340 and the secondary coil 350, the specifications of the primary coil 340 and the secondary coil 350 are strictly limited by the specifications of the bobbin parts 320" and 330".

[0171] Meanwhile, in the transformer 300 according to another embodiment, the coil fixing portion has flexibility, so that the primary coil 340 and the secondary coil 350 can be wound and fixed even if their specifications are slightly changed.

[0172] Furthermore, when current flows through the primary coil 340 and the secondary coil 350, heat is generated and resistance increases. However, in the transformer 300″ according to the comparative example, the entire upper surfaces of the primary coil 340 and the secondary coil 350 are covered by an upper plate (e.g., 333″) due to the bobbin parts 320″ and 330″, making it difficult to dissipate heat. As heat dissipation becomes more difficult, heat generation increases, and increased heat leads to increased resistance in the coils. Increased resistance causes increased loss and reduces efficiency.

[0173] Meanwhile, the transformers 300 and 300′ according to other embodiments are flexible but do not cover the entire upper surfaces of the primary coil 340 and secondary coil 350, which increases the heat transfer path in the accommodation space within the core part 310 and is also advantageous for heat dissipation.

[0174] The effect of excellent heat dissipation will be explained with reference to FIG.

[0175] Figure 18 shows the results of a heat generation test of a transformer according to another embodiment in comparison with a comparative example. For ease of understanding, (a), (c), and (e) of Figure 18 show the state in which the upper core 311 is removed, but it should be noted that the experiment was carried out with the upper core 311 still attached.

[0176] FIG. 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). FIG. 18(c) shows a modified comparative example in which only the upper plate of the first bobbin 320″ in the transformer according to the comparative example is replaced with a core fixing part, and FIG. 18(d) shows a thermal image of the transformer shown in FIG. 18(c). FIG. 18(e) shows a transformer 300 according to another embodiment, and FIG. 18(f) shows a thermal image of the transformer 300 according to another embodiment.

[0177] Table 2 below summarizes the experimental results for each case shown in FIG.

[0178] [Table 2]

[0179] 18 and Table 2, it can be seen that under the same operating conditions, the temperatures of both the core and primary coil decrease from the comparative example to the other examples. It can also be seen that the decrease in temperature reduces losses and increases the quality factor.

[0180] 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.

Claims

1. a core portion including an upper core and a lower core; a coil portion partially disposed within the core portion; a bobbin portion disposed between the core portion and the coil portion, The coil portion includes a primary coil and a coil portion at least partially disposed on a side surface of the primary coil. A secondary coil is included. The core portion includes a first outer leg portion, a second outer leg portion, and a portion between the first outer leg portion and the second outer leg portion. a midfoot portion disposed at The shortest distance between the primary coil and the secondary coil is 0.1 to 0.5 times the shortest distance to an adjacent one of the first outer leg portion and the second outer leg portion Transformers, which is 0.3 times larger.

2. The bobbin portion is a first bobbin having a first housing portion for housing the primary coil; a second bobbin having a second housing portion formed therein for housing the secondary coil, The first bobbin has a first extension portion extending from the first receiving portion toward the second bobbin. Including, The transformer according to claim 1 , wherein the second housing portion is disposed on the first extension portion. -.

3. The shortest distance from the bottom surface of the lower core to the primary coil and the shortest distance from the bottom surface of the lower core to the The transformer of claim 2 , wherein the distance is different from the shortest distance to the secondary coil.

4. The second bobbin has a second extension portion extending from the second receiving portion toward the first bobbin. Including, The transformer according to claim 3 , wherein the first housing portion is disposed below the second extension portion. Mah.

5. a part of the second housing portion is disposed between the primary coil and the secondary coil; 5. The transformer according to claim 4.

6. The core portion is a bobbin portion formed between the first outer leg portion and the middle leg portion to accommodate a portion of the bobbin portion; A first space; The other part of the bobbin part is formed between the second outer leg part and the middle leg part. The transformer of claim 1 , further comprising a second space.

7. The shortest distance between the primary coil and the secondary coil outside the first space and the second space The primary coil and the second coil are connected to each other within the first space or the second space at a first distance. The ratio of the second distance, which is the shortest distance between the secondary coil and the coil, is 1 to 1.

3. Transformers.

8. The shortest distance from the bottom surface of the lower core to the primary coil is 4. The transformer according to claim 3, wherein the distance is 0.3 to 0.7 times the shortest distance to the secondary coil. Mah.

9. The first bobbin is A first top portion; a first bottom portion disposed below the top portion; a first middle portion disposed between the top portion and the bottom portion, The transformer of claim 2 , wherein the first extension is disposed on the bottom portion.

10. The second bobbin is A second top portion; a second bottom portion disposed below the top portion; a second middle portion disposed between the second top portion and the second bottom portion, The first bobbin is defined by a lower surface of the second top portion and an inner surface of the second middle portion.

10. The transformer of claim 9, wherein the transformer is at least partially received in a recess defined by the at least one axially extending portion.

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