Transformer

Abstract

A transformer of an embodiment comprises: a core portion including an upper core and a lower core disposed in a first direction opposite to the upper core; a bobbin portion disposed at least partially within the core portion; and a coil portion including a primary coil and a secondary coil disposed at least partially on the bobbin portion, wherein the core portion forms a receiving space with the bobbin portion to receive the coil portion, and the primary coil and the secondary coil are disposed in a second direction intersecting the first direction in the receiving space and are disposed to overlap each other in the first direction on the outside of the receiving space.

Description

Transformers

[0001] The embodiment relates to a transformer.

[0002] The power supply of electronic devices is equipped with various coil components such as transformers and line filters.

[0003] Transformers can be incorporated into electronic devices for a variety of purposes. For example, they can be used to transfer energy from one circuit to another. They can also be used to change the voltage level, either by stepping up or stepping down. Furthermore, transformers, which only have inductive coupling between their primary and secondary windings and thus no direct DC path, can be used to block DC and pass AC, or to provide insulation between two circuits.

[0004] To ensure leakage inductance in these transformers, the primary and secondary coils must be arranged horizontally. However, in slim transformers, horizontally arranging the primary and secondary coils increases the overall area of ​​the transformer, requiring improvement. Furthermore, the leakage inductance of the transformer is not a net characteristic, and extremely low leakage inductance is required for high-frequency operation in LLC circuits.

[0005] The embodiment provides a transformer having reduced leakage inductance.

[0006] A transformer according to one embodiment includes a core portion including an upper core and a lower core arranged in a first direction opposite to the upper core; a bobbin portion at least partially arranged within the core portion; and a coil portion including a primary coil and a secondary coil at least partially arranged on the bobbin portion, wherein the core portion forms an accommodation space with the bobbin portion to accommodate the coil portion, and the primary coil and the secondary coil are arranged in a second direction intersecting the first direction in the accommodation space, and may be arranged to overlap in the first direction outside the accommodation space.

[0007] For example, the bobbin portion may include a core region overlapping the core portion in the first direction and defining the receiving space together with the upper core and the lower core; a first non-core region extending from the core region in a third direction intersecting the first direction and the second direction simultaneously; and a second non-core region formed by extending from the core region to face the first non-core region.

[0008] For example, the primary coil and the secondary coil may be arranged in the second direction in the core region and may be arranged in at least one of the first or second non-core regions so that at least a portion of the primary coil and the secondary coil may overlap each other in the first direction.

[0009] For example, the primary coil may include a first inner portion disposed in the core region; and a first outer portion disposed in the first non-core region; the secondary coil may include a second inner portion disposed in the core region; and a second outer portion disposed in the second non-core region and including an end of the secondary coil; and a plurality of third outer portions disposed in the first non-core region to connect the second inner portions.

[0010] For example, the plurality of third outer portions may include an upper third outer portion extending from one of the second inner portions and positioned above the first outer portion; and a lower third outer portion extending from the other of the second inner portions and positioned below the first outer portion, wherein the first outer portion may be positioned so that at least a portion overlaps with the upper third outer portion and the lower third outer portion in the first direction.

[0011] For example, the first non-core region of the bobbin portion may include a receiving groove in which the first outer portion of the primary coil is received; an upper receiving groove in which the upper third outer portion is received and positioned above the receiving groove; and a lower receiving groove in which the lower third outer portion is received and positioned below the receiving groove.

[0012] For example, the first height from the reference plane of the first non-core region to the uppermost surface of the upper third outer portion of the secondary coil may be less than or equal to the second height from the reference plane to the uppermost surface of the core portion.

[0013] For example, the first distance from the lowest surface of the lower third outer portion to the highest surface of the upper third outer portion may be less than or equal to the second distance from the lowest surface of the lower core to the highest surface of the upper core.

[0014] For example, the first non-core region may include a first guide groove protruding in the third direction from one side in contact with the core portion and spaced apart in the first direction to accommodate one end of the secondary coil; and a second guide groove protruding in the third direction from the other side in contact with the core portion and spaced apart in the first direction to accommodate the other end of the secondary coil.

[0015] For example, the first guide groove may have a shape that guides one end of one of the pair of secondary coils to extend to the upper mounting groove and guides one end of the other of the pair of secondary coils to extend to the lower mounting groove, and the second guide groove may have a shape that guides the other end of one of the secondary coils to extend to the upper mounting groove and guides the other end of the other of the secondary coils to extend to the lower mounting groove.

[0016] For example, the first direction and the second direction may be perpendicular to each other, and the second direction and the third direction may be perpendicular to each other.

[0017] The transformer according to the embodiment has a small horizontal size, reduced leakage inductance, and improved secondary coil imbalance and DCR.

[0018] The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present invention belongs from the description below.

[0019] Figure 1a is a top perspective view of a transformer according to an embodiment.

[0020] Figure 1b is a bottom perspective view of a transformer according to an embodiment.

[0021] Figure 2a shows a joint plan view of the transformer illustrated in Figures 1a and 1b.

[0022] Figure 2b shows a perspective view of the combined top of the transformer shown in Figures 1a and 1b.

[0023] Figure 2c is a combined bottom perspective view of the transformer shown in Figures 1a and 1b.

[0024] Figure 2d shows a front view of the combined transformer shown in Figures 1a and 1b.

[0025] Figure 2e is an enlarged view of the 'A' portion shown in Figure 2d.

[0026] Figure 3a shows a perspective view of the transformer illustrated in Figure 2c with the upper core removed.

[0027] Figure 3b shows a plan view of the transformer illustrated in Figure 3a.

[0028] Figure 3c shows a plan view of the coupling of only the coil section and the bobbin section in the transformer illustrated in Figure 3a.

[0029] Figure 3d shows a bottom view of the combined coil section and bobbin section of the transformer illustrated in Figure 3a.

[0030] Figure 4 shows a perspective view of Figure 3a with the primary coil removed.

[0031] Fig. 5a shows a cross-sectional view according to an embodiment taken along line I-I' in Fig. 3c.

[0032] Figure 5b shows a right side view of the transformer illustrated in Figure 3c viewed in the -x-axis direction.

[0033] The present invention is susceptible to various modifications and embodiments. Specific embodiments are illustrated and described in the drawings. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0034] Terms including ordinal numbers, such as "second," "first," etc., may be used to describe various components, but the components are not limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, a second component may be referred to as a "first component," and similarly, a first component may also be referred to as a "second component." The term "and / or" includes a combination of multiple related items described herein or any of multiple related items described herein.

[0035] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0036] In the description of the embodiments, the description that each layer (film), region, pattern or structure is formed "on" or "under" the substrate, each layer (film), region, pad or pattern includes both being formed directly or through the interposition of another layer. The reference to "on" or "under" each layer is explained based on the drawings. In addition, the thickness or size of each layer (film), region, pattern or structure in the drawings may be modified for clarity and convenience of explanation, and therefore does not entirely reflect the actual size.

[0037] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprise" or "have" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0038] 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 defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0039] Hereinafter, a transformer according to an embodiment will be described in detail with reference to the attached drawings. Regardless of the drawing reference numerals, identical or corresponding components will be given the same reference numerals, and redundant descriptions thereof will be omitted. In addition, although the transformer according to the embodiment will be described using the Cartesian coordinate system, it will be understood that the transformer may be described using another coordinate system. In the Cartesian coordinate system, the x-axis, the y-axis, and the z-axis illustrated in each drawing are orthogonal to each other, but the embodiment is not limited thereto. The x-axis, the y-axis, and the z-axis may also intersect each other. Hereinafter, for convenience of description, the z-axis direction will be referred to as the 'first direction', the y-axis direction will be referred to as the 'second direction', and the x-axis direction will be referred to as the 'third direction'.

[0040] Fig. 1a is a top perspective view of a transformer according to an embodiment, and Fig. 1b is a bottom perspective view of a transformer according to an embodiment, showing the transformer illustrated in Fig. 1a rotated 180°.

[0041] FIG. 2a shows a combined plan view of the transformers shown in FIGS. 1a and 1b, FIG. 2b shows a combined upper perspective view of the transformers shown in FIGS. 1a and 1b, FIG. 2c is a combined lower perspective view of the transformers shown in FIGS. 1a and 1b, showing the transformer shown in FIG. 2c rotated 180°, FIG. 2d shows a combined front view of the transformers shown in FIGS. 1a and 1b, and FIG. 2e is an enlarged view of part 'A' shown in FIG. 2d.

[0042] In addition, FIG. 3a shows a perspective view of the transformer shown in FIG. 2c with the upper core (110) removed, FIG. 3b shows a plan view of the transformer shown in FIG. 3a, FIG. 3c shows a plan view of the combination of only the coil part (200) and the bobbin part (300) in the transformer shown in FIG. 3a, and FIG. 3d shows a bottom view of the combination of only the coil part (200) and the bobbin part (300) in the transformer shown in FIG. 3a, which shows the transformer shown in FIG. 3c rotated 180°.

[0043] Figure 4 shows a perspective view of Figure 3a with the primary coil (210) removed.

[0044] For convenience of explanation, the illustration of the secondary coil (220) is omitted in Fig. 4.

[0045] A transformer according to an embodiment may include a core portion (100), a coil portion (200), and a bobbin portion (300).

[0046] The core part (100) has the characteristics of a magnetic circuit and can act as a path for magnetic flux. The core part (100) can include an upper core (110) and a lower core (120). The upper core (110) and the lower core (120) can be divided in a first direction, and when the upper core (110) and the lower core (120) are combined, one core part (100) can be formed. That is, the lower core (120) can be arranged to face the upper core (110) in the first direction. At this time, the upper core (110) can be defined as a core located farthest from the upper surface of the circuit board in the first direction, and the lower core (120) can be defined as a core located closest to the upper surface of the circuit board in the first direction. The upper core (110) and the lower core (120) can have shapes that are symmetrical with respect to each other in the vertical direction, i.e., in the z-axis direction, or can have asymmetric shapes. However, in the description below, for convenience of explanation, it is assumed that the shape is symmetrical vertically.

[0047] A first outer foot portion (111) protruding downwardly in the first direction and extending along a third direction may be arranged on one side of the upper core (110) in the second direction. In addition, a second outer foot portion (112) protruding downwardly in the first direction and extending along a third direction may be arranged on the other side of the upper core (110) in the second direction. In addition, a midfoot portion (113) protruding downwardly in the first direction and extending along the third direction may be arranged between the first outer foot portion (111) and the second outer foot portion (112). The first outer foot portion (111), the second outer foot portion (112), and the midfoot portion (113) may be arranged to be parallel to each other. In addition, the widths of the first outer foot portion (111), the second outer foot portion (112), and the midfoot portion (113) in the second direction may be the same or different.

[0048] Meanwhile, a first outer portion (121), a second outer portion (122), and a mid-foot portion (123) may be arranged opposite the upper core (110) on the lower core (120). For example, the mid-foot portions (113, 123) may have a rectangular or elliptical planar shape as illustrated, but the embodiment is not limited to a specific shape of the mid-foot portions (113, 123).

[0049] The core portion (100) may further include a first space (130) and a second space (140). The first space (130) is formed between the first outer portion (111, 121) and the middle portion (113, 123), and may accommodate a coil portion (200) and a part of the bobbin portion (300) to be described later. The second space (140) is formed between the second outer portion (112, 122) and the middle portion (113, 123), and may accommodate a part of the coil portion (200) and a part of the bobbin portion (300) to be described later, which are arranged on the opposite side of the y-axis. Accordingly, the first space (130) and the second space (140) can be formed to correspond to the thickness and spacing of a part and the other part of the coil part (200) and the bobbin part (300) accommodated therein (130, 140). By adjusting the size of the first space (130) and the second space (140), the inductance of the core part (100) can be controlled, and the heat generation of the transformer can be controlled depending on the number of the first space (130) and the second space (140). The core part (100) may include a magnetic material, for example, iron or ferrite, but is not necessarily limited thereto.

[0050] The coil section (200) may include a primary coil (210) and a secondary coil (220).

[0051] A portion of the primary coil (210) may be disposed within the core portion (100), and the other portion of the primary coil (210) may be disposed outside the core portion (100). The primary coil (210) may have a shape of a winding or a plane, but the embodiment is not limited to a specific shape of the primary coil (210). In this way, at least a portion of the primary coil (210) may be accommodated in the first space (130) and the second space (140).

[0052] The primary coil (210) can also secure the individual withstand voltage of the transformer by applying reinforced insulation wire. When developing magnetic components such as transformers, there are withstand voltages required for the individual components being developed. Generally, the withstand voltage requires a certain multiple of the operating voltage of the component. Accordingly, in the case of components wound using conventional UTSC wire, an insulation distance is created to secure the withstand voltage to satisfy the withstand voltage.

[0053] The primary coil (210) can be used by applying an insulated reinforced wire, i.e., coating the entirety of the plurality of primary coil windings with an insulating synthetic resin, for example, epoxy. In this way, the overall strength of the winding form can be increased through the application of an insulated reinforced wire, and based on this, the overall rigidity of the transformer can also be improved.

[0054] The secondary coil (220) is arranged along the outer circumference of the primary coil (210) in the winding direction of the primary coil (210), and at least a portion of the secondary coil (220) can be accommodated in the first space (130) and the second space (140) together with the primary coil (210). The secondary coil (220) can also be wound by arranging a plurality of secondary windings in a single layer or multiple layers.

[0055] Meanwhile, the bobbin section (300) is a section where the core section (100) and the coil section (200) are connected, and a first non-core region (NCA1) (or first end) is arranged on one side, a second non-core region (NCA2) (or second end) is arranged on the other side opposite to the one side in the third direction, and a core region (CA) may be arranged between the first non-core region (NCA1) and the second non-core region (NCA2).

[0056] At least a portion of the primary coil (210) and the secondary coil (220) can be placed on the bobbin part (300).

[0057] In the bobbin part (300), the core area (CA) is defined as an area that overlaps with the core part (100) in a first direction that is perpendicular to the core part (100). In this way, at least a portion of the bobbin part (300) can be disposed within the core part (100). That is, the core part (100) can be disposed in the core area (CA) of the bobbin part (300). The upper core (110) and the lower core (120) of the core part (100) can define an accommodation space together with the core area (CA) of the bobbin part (300). At least a portion of the coil part (200) can be accommodated in the accommodation space defined in this way.

[0058] In the bobbin section (300), the first and second non-core regions (NCA1, NCA2) do not overlap vertically with the core section (100), and, more specifically, extend in a third direction, which is one of the horizontal directions, from the core section (CA), and are defined as regions arranged on opposite sides in the third direction with the core section (CA) interposed therebetween. That is, the first non-core region (NCA1) is a region extending in the third direction from the core section (CA), and the second non-core region (NCA2) is a region extending from the core section (CA) to face the first non-core region (NCA1).

[0059] Accordingly, the remaining area of ​​the bobbin section (300) excluding the first non-core area (NCA1) and the second non-core area (NCA2) can be understood as the core area (CA).

[0060] The bobbin portion (300) may include terminal portions (OL1, OL2) arranged in each of the first non-core region (NCA1) and the second non-core region (NCA2). The first terminal portion (OL1) is a portion where the end of the primary coil (210) is arranged, and may have a groove shape that receives and holds the end of the primary coil (210). For example, the first terminal portion (OL1) may include three terminal portions (OL11, OL12, OL13), but the embodiment is not limited to a specific number or shape of the first terminal portion (OL1).

[0061] In addition, the second terminal portion (OL2) is a portion where the end of the secondary coil (220) is placed, and may have a groove shape that receives and holds the end of the secondary coil (220). For example, the second terminal portion (OL2) may include four terminal portions (OL21, OL22, OL23, OL24), but the embodiment is not limited to a specific number or shape of the second terminal portion (OL2).

[0062] The aforementioned primary coil (210) may include a first inner portion (IP1) and a first outer portion (OP1). The portion of the primary coil (210) disposed in the core region (CA) is referred to as the first inner portion (IP1), and the portion disposed in the first non-core region (NCA1) is referred to as the first outer portion (OP1).

[0063] The secondary coil (220) may include a second inner portion (IP2), and second and third outer portions (OP2, OP3). The portion of the secondary coil (220) disposed in the core region (CA) is referred to as the second inner portion (IP2), and the portion disposed in the second non-core region (NCA2) is referred to as the second outer portion (OP2). An end of the secondary coil (220) belongs to the second outer portion (OP2). In addition, the portion of the secondary coil (220) disposed in the first non-core region (NCA1) is referred to as the third outer portion (OP3). The third outer portion (OP3) serves to connect the second inner portions (IP2) that are spaced apart from each other with the first inner portion (IP1) therebetween.

[0064] The secondary coil (220) may be formed as a pair (222, 224). In this case, one end and the other end of one (222) of the pair of secondary coils (220) are respectively disposed at the second and fourth second terminal portions (OL22, OL24) and have a planar shape that surrounds the outer surface of the primary coil (210). One end and the other end of the other (224) of the pair of secondary coils (220) are respectively disposed at the first and third second terminal portions (OL21, OL23) and have a planar shape that surrounds the outer surface of the primary coil (210).

[0065] According to an embodiment, the primary coil (210) and the secondary coil (220) are arranged in a horizontal direction, i.e., a second direction, within the receiving space formed by the bobbin portion (300) and the core portion (100), and do not overlap in the first direction, which is a vertical direction, but may be arranged to overlap in the first direction, which is a vertical direction, outside the receiving space. For example, the embodiment is specifically described as follows with reference to FIGS. 1A to 4, but is not limited thereto.

[0066] That is, in the transformer according to the embodiment, if the primary coil (210) and the secondary coil (220) are arranged horizontally in the core area (CA) of the bobbin portion (300) and do not overlap in the first direction, which is the vertical direction, but the primary coil (210) and the secondary coil (220) can be arranged to overlap in the first direction, which is the vertical direction, in at least one of the first and second non-core areas (NCA1, NCA2), the transformer according to the embodiment can also be applied to a transformer having a configuration different from the configuration illustrated in FIGS. 1A to 4.

[0067] Fig. 5a shows a cross-sectional view according to an embodiment cut along the line I-I' in Fig. 3c, and Fig. 5b shows a right side view of the transformer illustrated in Fig. 3c viewed in the -x-axis direction.

[0068] Referring to FIG. 5A, the primary coil (210) and the secondary coil (220: 222, 224) are arranged horizontally in the core area (CA) and do not overlap in the first direction, which is the vertical direction. On the other hand, the primary coil (210) and the secondary coil (220: 222, 224) may be arranged in at least one of the first or second non-core areas (NCA1, NCA2), for example, the first non-core area (NCA1), and may be arranged to overlap in the first direction, which is the vertical direction.

[0069] That is, the third outer side (OP3) of the secondary coil (224), which is one of a pair of secondary coils (220: 222, 224), extends from the second inner side (IP2) and is positioned above the first outer side (OP1) of the primary coil (210), and is therefore hereinafter referred to as an 'upper third outer side', and the third outer side (OP3) of the secondary coil (222), which is the other of a pair of secondary coils (220: 222, 224), extends from the second inner side (IP2) and is positioned below the first outer side (OP1) of the primary coil (210), and is therefore hereinafter referred to as a 'lower third outer side'. In this way, according to the embodiment, the first outer portion (OP1) of the primary coil (210) can be arranged so that at least a portion overlaps with the upper third outer portion and the lower third outer portion in a first direction that is perpendicular to each other.

[0070] In order for the secondary coil (220) to be vertically stacked above and below the primary coil (210) in the first non-core area (NCA1), referring to FIG. 2d, the first non-core area (NCA1) of the bobbin part (300) may include a receiving groove (RH), an upper mounting groove (RHU), and a lower mounting groove (RHL). Here, the receiving groove (RH) is not visible, but is indicated by a dotted line to aid understanding.

[0071] The receiving groove (RH) is a groove in which the first outer part (OL1) of the primary coil (210) is received, the upper mounting groove (RHU) is a groove in which the upper third outer part (OL3) is received and is positioned above the receiving groove (RH), and the lower mounting groove (RHL) is a groove in which the lower third outer part (OL3) is received and can be positioned below the receiving groove (RH).

[0072] Additionally, the bobbin section (300) may include a first non-core area (NCA1) and first and second guide grooves (GH1, GH2).

[0073] The first guide groove (GH1) protrudes in a third direction, i.e., in the x-axis direction, from one side of the first non-core area (NCA1) of the bobbin part (300) that is in contact with the core part (100) and is spaced apart in the vertical z-axis direction to accommodate one end of the secondary coil (220: 222, 224). The second guide groove (GH2) protrudes in a third direction from the other side of the first non-core area (NCA1) of the bobbin part (300) that is in contact with the core part (100) and is spaced apart in the vertical z-axis direction to accommodate the other end of the secondary coil (220: 222, 224).

[0074] The first guide groove (GH1) has a shape that guides one end of the secondary coil (224), which is one of a pair of secondary coils (222, 224), to extend to the upper mounting groove (RHU), and guides one end of the secondary coil (222), which is the other of a pair of secondary coils (222, 224), to extend to the lower mounting groove (RHL).

[0075] The second guide groove (GH2) has a shape that guides the other end of the secondary coil (224), which is one of a pair of secondary coils (222, 224), to extend to the upper mounting groove (RHU), and guides the other end of the secondary coil (222), which is one of a pair of secondary coils (222, 224), to extend to the lower mounting groove (RHL).

[0076] In this way, a pair of secondary coils (222, 224) can be wound by turning them over once by the first and second guide grooves (GH1, GH2), but the embodiment is not limited thereto.

[0077] Additionally, the first and second guide grooves (GH1, GH2) can also serve to support the secondary coil (224) and the secondary coil (222).

[0078] According to an embodiment, as illustrated in FIG. 5b, a first height (H1) from the reference plane (RS) of the first non-core region (NCA1) to the uppermost surface of the upper third outer portion of the secondary coil (224) may be less than or equal to a second height (H2) from the reference plane (RS) to the uppermost surface (100T) of the core portion (100).

[0079] For example, the reference surface (RS) may be the top surface (300T) of the bobbin portion (300) in the first non-core region (NCA1) as illustrated.

[0080] Alternatively, the first distance (D1) from the lowest surface (222BS) of the lower third outer portion (222) to the highest surface (224TS) of the upper third outer portion (224) may be less than or equal to the second distance (T5) from the lowest surface (120BS) of the lower core (120) to the highest surface (100T) of the upper core (110).

[0081] For example, the sum of the thickness (T1) of the first outer portion (OP1) of the first coil (210), the thickness (T2) of the upper third outer portion (OP3) of the second coil (224), the thickness (T3) of the lower third outer portion (OP3) of the second coil (222), and the thickness (T4) of the first non-core area (NCA1) of the bobbin portion (300) may be less than or equal to the thickness (T5) of the core portion (100).

[0082] Below, the transformers of the comparative examples and the examples are compared as follows.

[0083] Unlike the embodiment, in the transformer according to the comparative example, both the primary coil (210) and the secondary coil (220) are arranged horizontally in the core area (CA) and the first non-core area (NCA1) of the bobbin portion (300) and do not overlap in the vertical direction. As a result, the horizontal size of the transformer according to the comparative example increases, the separation distance between the secondary coil (220) arranged in the first non-core area (NCA1) and the core portion (100) increases, and the separation distance between the primary coil (210) and the secondary coil (220) arranged in the first non-core area (NCA1) may increase. As a result, the leakage inductance may increase.

[0084] On the other hand, according to the embodiment, the secondary coils (224, 222) are vertically overlapped and arranged above and below the primary coil (210) in the first non-core area (NCA1) of the bobbin part (300). Therefore, the horizontal size of the transformer according to the embodiment can be reduced compared to the comparative example. In addition, the separation distance in the third direction between the secondary coil (220) arranged in the first non-core area (NCA1) and the core part (100) can be reduced compared to the comparative example, and the separation distance between the primary coil (210) and the secondary coil (220) arranged in the first non-core area (NCA1) can be reduced compared to the comparative example, so that the leakage inductance can be reduced.

[0085] As an experimental example, in each of the comparative example and the exemplary embodiment, it is assumed that the length of the primary coil (210) protruding in the third direction from the core part (100) is 0.6 mm, the winding width of the primary coil (210) is 8.4 mm, and the turns ratio of the transformer and the shape of the core part (100) are fixed. At this time, in the case of the transformer according to the comparative example, when the distance in the third direction from the core part (100) to the outermost part of the secondary coil (220) is 18 mm and in the case of the transformer according to the exemplary embodiment, when the distance in the third direction from the core part (100) to the outermost part of the secondary coil (220: 222, 224) is 2.9 mm, the leakage inductance (Lk) of the comparative example and the exemplary embodiment can be obtained as follows.

[0086] Gap (mm) Comparative Example Example LLkLLk200206.444.5209.839.6250171.141.4173.737.2300146.539.2148.835.2350128.537.2130.633.5400114.835.4116.632.0

[0087] Here, the gap represents the separation distance in the first direction between the intermediate legs (113, 123), and L represents the inductance.

[0088] Referring to Table 1 above, it can be seen that the leakage inductance (Lk) is reduced by approximately 10% in the embodiment compared to the comparative example.

[0089] In addition, in the case of the embodiment, as illustrated in FIG. 5b, the sum of the thicknesses (T1 to T4) is less than or equal to the thickness (T5) of the core portion (100). Therefore, even if the primary coil (210) and the secondary coils (222, 224) are vertically stacked in the first non-core region (NCA1), the thickness of the transformer does not increase. In addition, the imbalance of the secondary coils (222, 224) and the coil resistance value, i.e., the direct current resistance (DCR), can be improved.

[0090] Although the above has been described focusing on embodiments, these are merely examples and do not limit the present invention. Those skilled in the art to which the present invention pertains will appreciate that various modifications and applications not exemplified above are possible without departing from the essential characteristics of the present embodiment. For example, each component specifically shown in the embodiments can be modified and implemented. In addition, differences related to such modifications and applications should be interpreted as being included within the scope of the present invention defined in the appended claims.

[0091] The mode for carrying out the invention has been sufficiently described in the above-mentioned “Best mode for carrying out the invention.”

[0092] The transformer according to the embodiment can be used in a power supply device of an electronic device, etc.

Claims

1. A core section including an upper core and a lower core arranged in a first direction opposite to the upper core; A bobbin portion at least partially disposed within the core portion; and A coil section including a primary coil and a secondary coil, at least part of which is disposed on the bobbin section, The core portion forms a receiving space with the bobbin portion to receive the coil portion, The above primary coil and the above secondary coil, In the above-mentioned receiving space, it is arranged in a second direction intersecting with the first direction, A transformer arranged to overlap in the first direction outside the above-mentioned receiving space.

2. In paragraph 1, The above bobbin part, A core region overlapping the core portion and the first direction and defining the receiving space together with the upper core and the lower core; and A transformer comprising a first non-core region extending from the core region in a third direction intersecting the first direction and the second direction simultaneously, and a second non-core region formed by extending from the core region so as to face the first non-core region.

3. In the second paragraph, the primary coil and the secondary coil is arranged in the second direction in the above core area, A transformer disposed in at least one of the first or second non-core regions and at least partially overlapping each other in the first direction.

4. In paragraph 3, The above primary coil a first inner portion disposed in the core region; and comprising a first outer portion disposed in the first non-core region; The above secondary coil a second inner portion disposed in the core region; and a second outer portion disposed in the second non-core region and including an end of the secondary coil; and A transformer comprising a plurality of third outer sections arranged in the first non-core region to connect the second inner sections.

5. In paragraph 4, The third outer portion of the plurality of above an upper third outer portion extending from one of the second inner portions and positioned above the first outer portion; and The second inner portion includes a lower third outer portion extending from another one of the above and positioned below the first outer portion, A transformer in which the first outer portion is arranged so that at least a portion thereof overlaps with the upper third outer portion and the lower third outer portion in the first direction.

6. In paragraph 5, The first non-core region of the above bobbin part A receiving groove in which the first outer portion of the first coil is received; An upper mounting groove in which the upper third outer portion is mounted and which is positioned above the receiving groove; and A transformer comprising a lower mounting groove disposed below the receiving groove and on which the lower third outer portion is mounted.

7. In paragraph 5, A transformer in which a first height from the reference plane of the first non-core region to the uppermost surface of the upper third outer portion of the secondary coil is less than or equal to a second height from the reference plane to the uppermost surface of the core portion.

8. In paragraph 5, A transformer in which a first distance from the lowest surface of the lower third outer portion to the highest surface of the upper third outer portion is less than or equal to a second distance from the lowest surface of the lower core to the highest surface of the upper core.

9. In paragraph 6, The above first non-core region is A first guide groove protruding in the third direction from one side in contact with the core portion and spaced apart in the first direction to accommodate one end of the secondary coil; and A transformer including a second guide groove protruding in the third direction from the other side in contact with the core portion and spaced apart in the first direction to accommodate the other end of the secondary coil.

10. In paragraph 9, The above first guide home One end of one of the pair of secondary coils is guided to extend into the upper mounting groove, and the other end of the pair of secondary coils is guided to extend into the lower mounting groove. The above second guide home A transformer having a shape that guides the other end of one of the secondary coils to extend into the upper mounting groove, and guides the other end of the other one of the secondary coils to extend into the lower mounting groove.

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