Transformer and flat panel display device including the same

Abstract

A transformer according to one embodiment includes a core portion having an upper core and a lower core, and a coil portion disposed in the core portion, wherein: the coil portion includes a first coil wound in a first direction, a second coil wound in a second direction opposite to the first direction, and a third coil having a flat plate shape; the lower core includes a body portion, a first leg portion and a second leg portion protruding from the body portion, and a spaced portion formed between the first leg portion and the second leg portion; the first leg portion includes two first outer legs and a first center leg disposed between the two first outer legs; the second leg portion includes two second outer legs and a second center leg disposed between the two second outer legs; the first coil can be disposed to encircle the first center leg, and the second coil can be disposed to encircle the second center leg.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a transformer and a flat panel display device including the same. BACKGROUND

[0002] Generally, driving power is required in order to drive an electronic device, and a power supply device such as a power supply unit (PSU) is basically used to supply the driving power to the electronic device.

[0003] In particular, a display device such as a flat panel television needs to be slim, and is continuously implemented in a larger size. Therefore, there is a need to reduce the thickness thereof while satisfying the increased power requirement of such a large display.

[0004] A transformer occupies a larger volume than other elements in a power supply unit (PSU). Therefore, one of the most important problems of a thin-type device is to reduce the thickness of the transformer.

[0005] Figure 1 FIG. 1 is an exploded perspective view showing an example of a configuration of a general thin-type transformer.

[0006] Referring to Figure 1 , a general thin-type transformer 10 includes a secondary coil 13 and a primary coil 14 disposed between an upper core 11 and a lower core 12. Generally, the secondary coil 13 is composed of a plurality of conductive metal plates, and the primary coil 14 is in the form of a wire wound. In another configuration, a bobbin (not shown) can be disposed between the upper core 11 and the lower core 12.

[0007] However, when the thickness of the transformer is reduced to a certain value (e.g., 11 mm) or less, there is a problem in that the performance is significantly deteriorated due to the characteristics of leakage inductance and parasitic capacitance. This will be described with reference to Figure 2a and Figure 2b

[0008] Figure 2a shows the relationship between the height variation of a thin-type transformer and leakage inductance, Figure 2b shows the relationship between the distance variation between a primary coil and a secondary coil and parasitic capacitance.

[0009] First, referring to Figure 2a ​Although there is a slight difference according to the relative size of a gap formed between the contact portions (generally, center legs) of the upper core 11 and the lower core 12, when the height of the transformer, for example, the distance from the upper surface of the upper core 11 to the lower surface of the lower core 12, is 13 mm or less, the leakage inductance becomes very low. The low leakage inductance is not preferable because the performance greatly fluctuates according to the load. The reason is that the LC resonance circuit composed of the transformer in the power supply unit (PSU) operates in a relatively narrow operating frequency band, and thus, the gain greatly varies according to the amount of power used. In order to secure sufficient leakage inductance to prevent problems caused by the low leakage inductance, a method of additionally providing a separate inductor including a core and a coil can be proposed. The reason is that the LC resonance circuit is transformed into an LLC resonance circuit in which the gain variation with respect to the operating frequency is less than the gain variation in the LC resonance circuit. However, the problem with the additional provision of the inductor is that a separate space in the power supply unit (PSU) is required to install the inductor.

[0010] Further, referring to Figure 2b When the vertical distance between the primary coil 14 and the secondary coil 13 is reduced, the parasitic capacitance sharply increases. For example, when the distance between the primary coil 14 and the secondary coil 13 is 200 μm or less, the size of the parasitic capacitance is 100 pF or more. In a general thin-type transformer, when the size of the parasitic capacitance is 100 pF or more, the performance is deteriorated due to the electric coupling, for example, the voltage increases at low power, the insulation is damaged, and the electromagnetic interference (EMI) characteristics are deteriorated.

[0011] In order to reduce the parasitic capacitance, the configuration of the secondary coil 13 can be modified from the conductive metal plate type to the conductive wire type. However, when the secondary coil is formed in the conductive wire type, a greater space is required inside the cores 11 and 12 to accommodate the secondary coil, resulting in an increase in the height of the transformer. Alternatively, in the case where the thickness of the cores 11 and 12 is reduced in order to secure a space for accommodating the secondary coil while maintaining the height of the transformer, the magnetic flux density in the cores increases, resulting in the generation of a greater amount of heat. SUMMARY

[0012] TECHNICAL PROBLEM

[0013] The technical task of the present disclosure is to provide a thin-type transformer capable of further miniaturization and a flat panel display device using the same.

[0014] Particularly, the technical task of the present disclosure is to provide a thin-type transformer capable of miniaturization while securing leakage inductance and a flat panel display device using the same.

[0015] Further, the technical task of the present disclosure is to provide a thin transformer capable of being miniaturized while reducing a parasitic capacitance and a flat panel display device using the same.

[0016] The technical task of the present disclosure is not limited to the above technical tasks, and other technical tasks not mentioned herein will be more clearly understood by those skilled in the art from the following description.

[0017] Technical Solution

[0018] A transformer according to one embodiment can include a core unit having an upper core and a lower core, and a coil unit disposed in the core unit. The coil unit can include a first coil wound in a first direction, a second coil wound in a second direction opposite to the first direction, and a third coil having a flat plate shape. The lower core can include a body portion, first and second leg portions protruding from the body portion, and a spaced portion formed between the first and second leg portions. The first leg portion can include two first outer legs and a first center leg disposed between the two first outer legs, and the second leg portion can include two second outer legs and a second center leg disposed between the two second outer legs. The first coil can be disposed to encircle the first center leg, and the second coil can be disposed to encircle the second center leg.

[0019] In one example, the second coil can be disposed on the first coil such that a portion of the second coil overlaps the first coil in a thickness direction.

[0020] In one example, the third coil can be disposed to encircle the first center leg.

[0021] In one example, the first coil and the second coil can have end portions drawn toward a first side, and the third coil can have an end portion drawn toward a second side opposite to the first side.

[0022] In one example, at least one of the first coil to the third coil can have a portion protruding outward beyond the core unit.

[0023] In one example, the two first outer legs and the two second outer legs can be disposed parallel to each other on a plane, and the first center leg and the second center leg can be disposed parallel to each other on the plane.

[0024] In one example, a total planar area of the first leg portion can be greater than a total planar area of the second leg portion.

[0025] In one example, a ratio of a planar area of the two first outer legs to a planar area of the first center leg or a ratio of a planar area of the two second outer legs to a planar area of the second center leg can be 0.65 to 0.8.

[0026] In one example, a ratio of a planar area of the second leg to a planar area of the core unit can be 0.04 to 0.08.

[0027] In one example, an insulation layer can be further disposed between the first coil and the second coil.

[0028] In one example, an insulation layer can be further disposed between the first coil and the third coil.

[0029] In one example, the transformer can further include a bobbin disposed in the core unit.

[0030] In one example, at least one of the upper core or the lower core can have a recess formed between the first central leg and the second central leg.

[0031] In one example, the transformer can further include a core short unit configured to electrically short the upper core and the lower core.

[0032] Further, a circuit board according to an embodiment can include a substrate, a circuit part formed on the substrate, and a transformer electrically connected to the circuit part. The transformer can include a core unit having an upper core and a lower core, and a coil unit disposed in the core unit. The coil unit can include a first coil wound in a first direction, a second coil wound in a second direction opposite to the first direction, and a third coil having a flat plate shape. The upper core can include a body part, first and second leg parts protruding from the body part, and a spacing part formed between the first leg part and the second leg part. The first leg part can include two first outer legs and a first central leg disposed between the two first outer legs, and the second leg part can include two second outer legs and a second central leg disposed between the two second outer legs. The first coil can be disposed to encircle the first central leg, and the second coil can be disposed to encircle the second central leg.

[0033] Advantageous Effects

[0034] The transformer according to an embodiment is provided with an inductor for ensuring leakage inductance by core sharing, and thus can reduce a size. Accordingly, a flat panel display device including the transformer can also be slimmed.

[0035] Further, according to the disclosure, due to the core short unit for shorting one core and another core, a parasitic capacitance can be reduced, such that performance deterioration due to electrical coupling can be prevented.

[0036] Effects that can be achieved through the disclosure are not limited to the above-mentioned effects, and other effects not mentioned herein will be clearly understood by those skilled in the art from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1is an exploded perspective view showing an example of a configuration of a general thin transformer.

[0038] Figure 2a shows a relationship between a height variation of a thin transformer and a leakage inductance, Figure 2b shows a relationship between a distance variation between a primary coil and a secondary coil and a parasitic capacitance.

[0039] Figure 3 is an exploded perspective view showing an example of a configuration of a transformer according to an embodiment.

[0040] Figure 4 shows an example of a configuration of a core according to an embodiment.

[0041] Figure 5 shows an example of a shape of a skeleton according to an embodiment.

[0042] Figure 6a is a view for explaining a winding direction of a transformer according to an embodiment.

[0043] Figure 6b is a view of an effect of a winding direction of a transformer according to an embodiment.

[0044] Figure 7 is a view for explaining a heat dissipation unit of a transformer according to an embodiment. DETAILED DESCRIPTION

[0045] BEST MODE

[0046] The present disclosure will now be described more fully with reference to the accompanying drawings, in which various embodiments are shown. The examples may, however, be embodied in many different forms and should not be construed as limiting. It should be understood that the present disclosure covers all modifications, equivalents, and alternatives falling within the idea and scope of the present disclosure.

[0047] Although including "second", "first", and the like ordinal numbers can be used to describe various components, they are not intended to limit the components. The expressions are used only to distinguish one component from another component. For example, a second element can be named a first element without departing from the scope of the present disclosure, and similarly, a first element can be named a second element. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0048] It should be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements can be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

[0049] In the description of embodiments, it will be understood that when an element such as a layer (film), a region, a pattern, or a structure is referred to as being "on" or "under" another element, the term "on" or "under" means that the element is "directly" formed on or under the other element, or "indirectly" formed on or under the other element with an intervening element therebetween such that the intervening element is also present. It will also be understood that the standard of on or under is based on the drawing. In addition, the thickness or size of the layer (film), region, pad, pattern, or structure shown in the drawings can be exaggerated, omitted, or schematically drawn for the purpose of explanation or convenience. And it can not accurately reflect the actual size.

[0050] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

[0051] 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. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined in the specification.

[0052] Hereinafter, a transformer according to one embodiment will be described in detail with reference to the accompanying drawings.

[0053] Figure 3 is an exploded perspective view showing an example of the configuration of a transformer according to one embodiment, and Figure 4 shows an example of the configuration of a core according to one embodiment.

[0054] For ease of explanation, the view of the skeleton is omitted from Figure 3 and an example of the configuration of the skeleton will be described later with reference to Figure 5

[0055] Reference will be made to Figure 3 and Figure 4 ​The transformer 100 according to one embodiment can include cores 111 and 112 and coils 120, 130, and 140. The coils 120, 130, and 140 can include a primary coil 120, a secondary coil unit 130, and an inductor coil 140. Hereinafter, the respective components will be described in detail.

[0056] The cores 111 and 112 can have a function of a magnetic path and can serve as a path of magnetic flux. The cores 111 and 112 can include an upper core 111 disposed at an upper position and a lower core 112 disposed at a lower position. The two cores 111 and 112 can be formed to be symmetrical or asymmetrical to each other in a vertical direction. However, for convenience of explanation, the following description will be made under the assumption that the two cores are formed to be vertically symmetrical to each other, and thus only one of the two cores, for example, the upper core 111, is illustrated in Figure 4

[0057] At least one of the upper core 111 or the lower core 112 constituting the cores 111 and 112 can include a body having a flat plate shape and a plurality of leg portions protruding from the body in a thickness direction and extending in a predetermined direction. The plurality of leg portions can include a first leg portion including two first outer legs TOL1 and TOL2 extending in one axial direction (for example, a y-axis direction) on a flat plane and spaced apart from each other in another axial direction (for example, an x-axis direction) thereon, and a first center leg TCL disposed between the two first outer legs TOL1 and TOL2, and a second leg portion including two second outer legs IOL1 and IOL2 extending in one axial direction (for example, a y-axis direction) and spaced apart from each other in another axial direction (for example, an x-axis direction), and a second center leg ICL disposed between the two second outer legs. In this case, the first leg portion and the second leg portion can be spaced apart from each other, and thus a gap, i.e., a spaced portion, can be formed therebetween.

[0058] Here, the first leg portion TOL1, TCL, and TOL2 mainly serve as a core of a transformer, and the second leg portion IOL1, ICL, and IOL2 mainly serve as a core of an inductor for securing leakage inductance. In other words, although each of the cores 111 and 112 according to one embodiment is implemented to have a single body (i.e., an integrated) structure, it performs the function of a core of two magnetic elements (i.e., a transformer and an inductor). The above structure facilitates miniaturization of the transformer compared to a structure in which a core for only a transformer and a core for only an inductor are disposed apart from each other.

[0059] ​The four outer legs TOL1, TOL2, IOL1, and IOL2 may have the same width a1, but this disclosure is not limited thereto. In one example, the widths of the first outer legs TOL1 and TOL2, which are mainly used as transformers, may be equal to each other, but may differ from the widths of the second outer legs IOL1 and IOL2, which are mainly used as inductors. Furthermore, the two center legs TCL and ICL may have the same width a2, but this disclosure is not limited thereto. In one example, the two center legs TCL and ICL may have different widths.

[0060] The first legs TOL1, TCL and TOL2, which are mainly used as the core of the transformer, and the second legs IOL1, ICL and IOL2, which are mainly used as the core of the inductor, can be spaced apart from each other by a predetermined distance b2 in one direction (y-axis direction). Therefore, gaps can be formed between the two first outer legs TOL1 and TOL2 and the two second outer legs IOL1 and IOL2, as well as between the first center leg TCL and the second center leg ICL.

[0061] In this case, the spacer portion can be used as a boundary to prevent the center leg and outer leg from extending along the y-axis and to isolate the part of the core that is mainly used as an inductor from the part of the core that is mainly used as a transformer.

[0062] Within the spacer portion, in the spacer portion formed between the first center leg TCL and the second center leg ICL, such as Figure 6a As shown, at least a portion of the primary coil 120 and at least a portion of the inductor coil 140 may overlap each other in the thickness direction (i.e., the z-axis direction). The structure where the two coils 120 and 140 overlap can be a structure requiring more space in the thickness direction within the center leg spacer, and can also generate a greater amount of heat due to the added heat generated from the overlapping coils 120 and 140. Therefore, to ensure coil space and promote heat dissipation, at least one of the upper core 111 or the lower core 112 may have a recess RC formed in the middle of its center leg spacer portion. Due to the formation of the recess RC, the thickness of the corresponding portion of the core is reduced, thus ensuring space for the coils to be disposed therein. Furthermore, the path along which heat is transferred upwards in the upper core 111 and the path along which heat is transferred downwards in the lower core 112 are shortened, thereby improving heat dissipation performance. Although in Figure 4 The recess RC formed in the upper core 111 is shown as being recessed along the z-axis and having a rectangular planar shape, but this disclosure is not limited thereto. Furthermore, it will be apparent to those skilled in the art that the recess can have any different dimensions.

[0063] On the other hand, in the case of one of the cores 111 and 112, for example, Figure 4The ratio of the sum of the planar areas of the four outer legs TOL1, TOL2, IOL1, IOL2 and the two two center legs TCL, ICL to the entire planar area of the upper core (i.e., a*b) can be 0.15 to 0.30. Thus, the ratio of the planar area of the remaining region where no outer leg or center leg is provided (hereinafter referred to as an "open region" or a "recess portion" for convenience of explanation) to the total planar area of the upper core can be 0.7 to 0.85.

[0064] When the ratio of the planar areas of the outer legs and the center legs to the total planar area increases, the series inductance increases, and the magnetizing inductance of the transformer decreases. Conversely, when the ratio of the planar area of the open region to the total planar area increases, the series inductance decreases, and the magnetizing inductance of the transformer increases.

[0065] The ratio of the area of the outer legs to the area of the center legs corresponds to a2:2*a1, which can be 0.65 to 0.8, but the present disclosure is not limited thereto. The reason for this is that the magnetic path formed by winding the wire is mainly formed around the center legs.

[0066] Further, the total planar area of the first legs TCL, TOL1, and TOL2 can be greater than the total planar area of the second legs ICL, IOL1, and IOL2.

[0067] Further, the ratio of the planar area of the inductor portion mainly used as an inductor to the total planar area of the core (i.e., b:b3) can be 0.04 to 0.08, but the present disclosure is not limited thereto. When this area ratio increases, the series inductance increases.

[0068] The above area ratio is a value obtained assuming that the number of turns between the primary coil 120 and the inductor coil 140 is 1:1. However, it will be apparent to those skilled in the art that the number of turns between the coils can be appropriately changed.

[0069] When the upper core 111 and the lower core 112 are vertically coupled to each other, each of the four outer legs TOL1, TOL2, IOL1, and IOL2 and the two center legs TCL and ICL of the upper core 111 face a corresponding one of the outer legs and the center legs of the lower core 112. In this case, a gap having a predetermined distance (for example, 10 to 100 µm, but not limited thereto) can be formed between at least one of the pairs of outer legs and the pairs of center legs facing each other. In other words, when the upper core 111 and the lower core 112 are coupled to each other, two pairs of center legs and four pairs of outer legs can be formed, and thus a maximum of six gaps can be formed. Accordingly, there is an advantage in that any one of various specifications can be implemented by controlling the positions at which the gaps are formed and the number of gaps. In one example, when the gaps are formed at a total of four points, specifically, the gaps are formed between a pair of center legs TCL mainly used as a transformer, between a pair of center legs ICL mainly used as an inductor, between a pair of outer legs IOL1, and between a pair of outer legs IOL2, it can be advantageous for maintaining inductance variation. In another example, when all six gaps are formed, it can be advantageous in terms of a heating characteristic since a heating portion is most distributed. Each gap can be formed in such a manner that a spacer having a predetermined thickness and being insulated is inserted between the center legs or the outer legs facing each other, but the disclosure is not limited thereto.

[0070] Meanwhile, each of the cores 111 and 112 can include a magnetic material, for example, iron or ferrite, but the disclosure is not limited thereto.

[0071] The primary coil 120 can be wound around the center leg TCL mainly used as a transformer, and the inductor coil 140 can be wound around the center leg ICL mainly used as an inductor. An insulating layer (not shown) can be provided on and under each of the coils 120 and 140 so that the coils 120 and 140 are insulated from the cores 111 and 112 and other coils 120, 130, and 140 adjacent thereto. The insulating layer can include at least one of ketone, polyimide-based material, polyethylene terephthalate (PET), silicone, or epoxy-based material, but the disclosure is not limited thereto.

[0072] Each of the primary coil 120 and the inductor coil 140 can be a multi-turn winding in which a rigid metal conductor, for example, a copper conductor, is wound multiple times in a spiral or planar spiral shape, but the disclosure is not limited thereto. For example, an enameled wire (USTC wire) wound by a fiber yarn, a stranded wire, a tri-insulated wire (TIW), or the like can be used for each of the coils 120 and 140.

[0073] The four end portions of the two conductor wires can be led out in the same direction, each end portion constituting a corresponding one of the primary coil 120 and the inductor coil 140.

[0074] The secondary coil unit 130 can include a first plate 131 and a second plate 132, each of which has a flat plate shape. Each of the first plate 131 and the second plate 132 can include an electrically conductive metal (e.g., copper or aluminum), and can have a planar shape symmetrical with both sides of the other one of the first plate 131 and the second plate 132, but the present disclosure is not limited thereto. Each of the first plate 131 and the second plate 132 can be turned once around the center leg TCL mainly used as a transformer. Preferably, the first plate 131 and the second plate 132 can be stacked with the aforementioned insulating layer interposed therebetween. The end portions of the plates 131 and 132 can be led out in the same direction. In this case, the direction in which the end portions of the plates 131 and 132 are led out can preferably be opposite to the direction in which the four end portions of the two conductive wires constituting the respective one of the primary coil 120 and the inductor coil 140 are led out, but the present disclosure is not limited thereto.

[0075] Meanwhile, a portion of at least one of the above-described coils 120, 130, and 140 can protrude outward beyond the cores 111 and 112.

[0076] Figure 5 An example of the shape of the skeleton according to one embodiment is illustrated. Unlike FIG. 2, the illustration of the primary coil 120, the secondary coil unit 130, and the inductor coil 140 is omitted in FIG. 3, and the skeleton 150 is additionally illustrated in FIG. 3. Figure 5 Figure 5 The skeleton 150 can be disposed between the upper core 111 and the lower core 112. The skeleton 150 can include an upper plate 151, a lower plate 152, a first hole 153, a second hole 154, a first terminal T1, and a second terminal T2.

[0077] Referring to Figure 5 , the skeleton 150 can be disposed between the upper core 111 and the lower core 112. The skeleton 150 can include an upper plate 151, a lower plate 152, a first hole 153, a second hole 154, a first terminal T1, and a second terminal T2.

[0078] The upper plate 151 and the lower plate 152 can be spaced apart from each other by a predetermined distance in a thickness direction (i.e., a z-axis direction), and the primary coil 120 and the inductor coil 140 can be wound and accommodated in the space. As described above, when the end portions of the conductive wires (the end portions of each of the conductive wires constitute the respective one of the primary coil 120 and the inductor coil 140) are led out in the same direction, each of the led-out end portions can be electrically conductively connected to a respective one of the plurality of individual terminals constituting the first terminal T1. Here, the lower plate 152 can be provided with an inclined portion 155 disposed adjacent to the first hole 152 and forming a passage inclined at a predetermined angle, so as to guide the end portions of the conductive wires constituting the primary coil 120 and the inductor coil 140 to the first terminal T1. Due to the inclined portion 155, the end portions of the conductive wires led out toward the first terminal T1 do not turn in the thickness direction without occupying the space between the upper plate 151 and the lower plate 152, thereby the number of windings can be increased.​

[0079] The secondary coil unit 130 can be disposed on a bottom surface of the lower plate 152, and end portions of the first plate 131 and the second plate 132 constituting the secondary coil unit 130 can be electrically connected to the second terminal T2. That is, due to the lower plate 152, the secondary coil unit 130 is spaced apart from the primary coil 120 and the inductor coil 140 by a distance at least equal to the thickness of the lower plate 152, thereby securing a sufficient distance for insulation.

[0080] Each of the plurality of individual terminals constituting the first terminal T1 and the second terminal T2 can have a flange type structure in which the plurality of individual terminals extend to a predetermined height in a direction away from the center of the skeleton 150 at a predetermined slope, and then are bent in a vertical direction. Due to this flange type structure, the transformer 100 can be mounted in a hole formed in a substrate of a power supply unit (PSU), thereby reducing the effect of the height of the transformer 100 in the power supply unit (PSU), thus further contributing to the manufacture of a thinner device. Here, the power supply unit (PSU) can include a circuit board including a substrate and a circuit portion formed on the substrate, and the transformer 100 can be electrically connected to the circuit portion on the circuit board.

[0081] Meanwhile, a center leg ICL of the inductor mainly serving as the cores 111 and 112 can pass through the first hole 153, and a center leg TCL of the transformer mainly serving as the cores 111 and 112 can pass through the second hole 154.

[0082] Hereinafter, the winding directions of the primary coil 120 and the inductor coil 140 will be described with reference to Figure 6a and Figure 6b

[0083] Figure 6a is a view for explaining the winding directions of the transformer according to one embodiment, and Figure 6b is a view of the effect of the winding directions of the transformer according to one embodiment.

[0084] First, referring to Figure 6a , the primary coil 120 and the inductor coil 140 according to the embodiment can be wound in opposite directions. In one example, the primary coil 120 can be wound in a clockwise direction, and the inductor coil 140 can be wound in a counterclockwise direction. Of course, this is illustrative. The primary coil 120 can be wound in a counterclockwise direction, and the inductor coil 140 can be wound in a clockwise direction. The reason why the winding directions of the primary coil 120 and the inductor coil 140 are opposite to each other will be described with reference to Figure 6b

[0085] First, referring to Figure 6b ​​the uppermost drawing in FIG. 10, when the primary coil 120 is wound in the clockwise direction and the inductor coil 140 is wound in the counterclockwise direction, the directions of the magnetic flux generated by the primary coil 120 and the magnetic flux generated by the inductor coil 140 are the same in each of the center legs, thus causing the magnetic flux to reinforce. On the other hand, the directions of the magnetic flux generated by the primary coil 120 and the magnetic flux generated by the inductor coil 140 are opposite to each other in each of the outer legs, thus causing the magnetic flux to cancel. According to experiments performed under the above conditions, an inductance of 4100 μH is generated when each of the primary coil 120 and the inductor coil 140 is wound thirteen times, and an inductance of 3610 μH is generated when each of the primary coil 120 and the inductor coil 140 is wound twelve times.

[0086] On the other hand, referring to Figure 6b the middle drawing in FIG. 10, when the winding direction of the primary coil 120 and the winding direction of the inductor coil 140 are the same, unlike the case in Figure 6a , magnetic flux cancellation occurs in each of the center legs, and magnetic flux reinforcement occurs in each of the outer legs. According to experiments performed under the above conditions, an inductance of 1946 μH is generated when each of the primary coil 120 and the inductor coil 140 is wound thirteen times, and an inductance of 1706 μH is generated when each of the primary coil 120 and the inductor coil 140 is wound twelve times. That is, compared to the case in which the winding directions are opposite to each other in Figure 6a , the inductance is significantly reduced. Thus, it can be seen that it is preferable that the winding direction of the primary coil 120 and the winding direction of the inductor coil 140 be opposite to each other in order to obtain a high leakage inductance value.

[0087] Meanwhile, referring to Figure 6b the lowermost drawing in FIG. 10, when the outer legs are formed in one body, although the winding direction of the primary coil 120 and the winding direction of the inductor coil 140 are opposite to each other, the magnetic flux cancellation that occurs in each of the outer legs has an effect on each of the center legs, thus reducing the reinforcement characteristics in each of the center legs. This case not only results in a reduction in the leakage inductance value, but also results in an increase in the generated heat. Thus, it is preferable that a spacing portion be formed to avoid the integration of the outer legs.

[0088] According to one embodiment of the present disclosure, a heat dissipation unit can be provided on each of the cores 111 and 112 in order to improve the heat dissipation performance. This will be described with reference to Figure 7 .

[0089] Figure 7 is a view for explaining a heat dissipation unit of a transformer according to one embodiment.

[0090] Referring to Figure 7The heat dissipation unit 160 can be disposed in an open area of at least one of the upper core 111 or the lower core 112 constituting the cores 111 and 112, for example, in an open area of a lower surface of the upper core 111 and / or an open area of an upper surface of the lower core 112. The heat dissipation unit 160 can be formed in the shape of a film including a material having excellent heat resistance and thermal conductivity, for example, at least one of graphite or a sheet of polyimide (PI) (Kapton) tape, but the present disclosure is not limited thereto. The heat dissipation unit 160 can extend to the outside of each of the cores 111 and 112 to be in contact with a housing or a heat sink of a power supply unit (PSU), thereby helping to quickly dissipate heat generated inside the transformer 100.

[0091] On the other hand, according to another embodiment, the transformer can further include a core short unit (not shown) to control a parasitic capacitance that increases as a vertical distance between the primary coil 120 and the secondary coil unit 130 decreases. The core short unit can be disposed on one or both of the surfaces of the cores 111 and 112 facing each other and can serve to electrically short the upper core 111 and the lower core 112. To achieve the shorting, at least a portion of the core short unit can be in contact with (that is, electrically connected with) the upper core 111, and at least a portion of a remaining portion thereof other than the portion in contact with the upper core 111 can be in contact with the lower core 112. Further, the core short unit can include an electrically conductive material to short the upper core 111 and the lower core 112 and can take the form of a thin film to slim down the transformer, but the present disclosure is not limited thereto. In one example, the core short unit can be a copper foil or can take the form of a wire having a circular or polygonal cross-section. In another example, the core short unit can take the form of a thin film having a planar shape that is a polygon other than a rectangle or a circle.

[0092] Although the present disclosure has been particularly shown and described with reference to exemplary embodiments thereof, these embodiments are presented by way of illustration only, and are not intended to limit the present disclosure in any manner, and it will be apparent to those skilled in the art that various changes in form and details can be made therein without departing from the essential characteristics of the embodiments described herein. For example, the respective configurations described in the embodiments can be modified and applied. Furthermore, differences from such modifications and applications should be interpreted as falling within the scope of the present disclosure defined by the appended claims.

Claims

1. A transformer, comprising: The core unit has an upper core and a lower core; A frame is disposed in the core unit, and the frame includes a first terminal and a second terminal; as well as A coil unit is disposed in the core unit. The coil unit includes: The first coil is wound in the first direction; The second coil is wound in a second direction opposite to the first direction; The third coil has a flat plate shape; and An insulating layer is disposed between the first coil and the second coil. The upper core includes: Main body part; The first leg and the second leg protrude from the body portion; and A spacer portion is formed between the first leg and the second leg. The first leg includes two outer legs and a central leg disposed between the two outer legs. The second leg includes two outer legs and a second central leg disposed between the two outer legs. The first coil is configured to surround the first central leg. The second coil is configured to surround the second central leg. The second coil is disposed on the first coil such that a portion of the second coil overlaps with the first coil in the thickness direction. Wherein, the first terminal is connected to the ends of the first coil and the second coil, and the second terminal is connected to the end of the third coil, and Each of the plurality of individual terminals constituting the first terminal and the second terminal has a flange structure.

2. The transformer according to claim 1, wherein, The third coil is configured to surround the first central leg.

3. The transformer according to claim 2, further comprising: An insulating layer is disposed between the first coil and the third coil.

4. The transformer according to claim 3, wherein, The planar area of ​​the first central leg is greater than the planar area of ​​the second central leg.

5. The transformer according to claim 1, wherein, The first coil and the second coil have ends extending toward the first side, and The third coil has an end extending toward a second side, which is opposite to the first side.

6. The transformer according to claim 1, wherein, At least one of the first to the third coils has a portion that protrudes outward beyond the core unit.

7. The transformer according to claim 1, wherein, The two first outer legs and the two second outer legs are arranged parallel to each other on a plane, and The first central leg and the second central leg are arranged parallel to each other on a plane.

8. The transformer according to claim 1, wherein, The total planar area of ​​the first leg is greater than the total planar area of ​​the second leg.

9. The transformer according to claim 7, wherein, The ratio of the planar area of ​​the two first outer legs to the planar area of ​​the first central leg, or the ratio of the planar area of ​​the two second outer legs to the planar area of ​​the second central leg, is between 0.65 and 0.

8.

10. The transformer according to claim 1, wherein, The ratio of the planar area of ​​the second leg to the planar area of ​​the core unit is 0.04 to 0.

08.

11. The transformer according to claim 1, wherein, At least one of the upper core or the lower core has a recess formed between the first center leg and the second center leg.

12. The transformer according to claim 1, further comprising: The skeleton is disposed in the core unit.

13. The transformer according to claim 1, further comprising: The core short-circuit unit is configured to electrically short-circuit the upper core and the lower core.

14. The transformer according to claim 1, wherein, The lower core is formed to be symmetrical to the upper core in the vertical direction, and When the upper core and the lower core are coupled to each other, a gap is formed between at least one of the two pairs of central legs facing each other and the four pairs of external legs facing each other.

15. The transformer according to claim 1, wherein, The third coil comprises multiple conductive metal plates stacked on top of each other.

16. The transformer according to claim 15, wherein, Each of the plurality of conductive metal plates comprises copper or aluminum.

17. The transformer according to claim 16, wherein, The plurality of conductive metal plates have a planar shape that is symmetrical about each other.

18. The transformer according to claim 17, wherein, Each of the plurality of conductive metal plates has a central end that is shortened in a central tap structure.

19. The transformer according to claim 1, further comprising: A heat dissipation unit is disposed in an open area of ​​at least one of the upper core or the lower core.

20. The transformer according to claim 19, wherein, The heat dissipation unit is in the form of a membrane, which includes at least one of graphite or polyimide Kapton tape.

21. The transformer according to claim 19, wherein, The heat dissipation unit extends to the outside of the core unit.

22. A circuit board, comprising: substrate; The circuit portion is formed on the substrate; as well as A transformer is electrically connected to the circuit section. The transformer includes: Core unit, having upper and lower cores; and A coil unit is disposed in the core unit. A frame, disposed in the core unit, the frame including a first terminal and a second terminal; and The coil unit includes: The first coil is wound in the first direction; The second coil is wound in a second direction opposite to the first direction; The third coil has a flat plate shape; and An insulating layer is disposed between the first coil and the second coil. The upper core includes: Main body part; The first leg and the second leg protrude from the body portion; and A spacer portion is formed between the first leg and the second leg. The first leg includes two outer legs and a central leg disposed between the two outer legs. The second leg includes two outer legs and a second central leg disposed between the two outer legs. The first coil is configured to surround the first central leg. The second coil is configured to surround the second central leg. The second coil is disposed on the first coil such that a portion of the second coil overlaps with the first coil in the thickness direction. Wherein, the first terminal is connected to the ends of the first coil and the second coil, and the second terminal is connected to the end of the third coil, and Each of the plurality of individual terminals constituting the first terminal and the second terminal has a flange structure.

Images