Transformer

Abstract

The present invention relates to a transformer comprising: a core unit having an upper core and a lower core disposed to face the upper core in a first direction; a coil unit comprising a primary coil and a secondary coil disposed to be insulated from the primary coil; and a bobbin which supports the coil unit in the core unit, wherein the bobbin may comprise: a pair of support units extending in a second direction intersecting a first direction, with a through-hole interposed therebetween, to support the coil unit in the core unit, the through-hole having open portions facing the bottom surface of the upper core and the top surface of the lower core in the first direction; a primary coil accommodation unit which is disposed on one side of each of the support units and to which a terminal pin is coupled to electrically connect the primary coil to a circuit board; and a secondary coil accommodation unit disposed on the other side of each of the support units to electrically connect the secondary coil to the circuit board, whereby, the transformer may have a structure that stably supports the coils while being reduced in thickness, and may be securely fixed due to an increased bonding area with the printed circuit board.

Description

Transformers

[0001] The present invention relates to a transformer.

[0002] The power supply of electronic devices is equipped with various magnetic coupling devices, such as transformers and line filters, and magnetic elements.

[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 have only 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] A typical slim transformer employs a structure in which the primary and secondary coils are stacked vertically. This stacking of the primary and secondary coils both contributes to the thickness, limiting the reduction in thickness. Furthermore, this results in a significantly lower leakage inductance. Leakage inductance must be maintained above a certain level for switching mode operation within the circuit.

[0005] Therefore, a transformer that can secure leakage inductance while being slimmer is required.

[0006] The purpose of the present invention is to provide a transformer having a structure capable of stably supporting a coil while reducing thickness.

[0007] Another object of the present invention is to provide a transformer that can be stably fixed by increasing the bonding area with a printed circuit board.

[0008] In order to achieve the above object, a transformer according to the present invention is characterized by comprising: a core portion having an upper core and a lower core arranged to face the upper core in a first direction; a coil portion including a primary coil and a secondary coil arranged to be insulated from the primary coil; and a bobbin supporting the coil portion within the core portion, wherein the bobbin includes a pair of support portions extending in a second direction intersecting the first direction, each of which is centered on a through hole having an open portion facing a lower surface of the upper core and an upper surface of the lower core in the first direction, to support the coil portion within the core portion; a primary coil receiving portion arranged on one side of the support portion and having a terminal pin coupled thereto for electrically connecting the primary coil to a circuit board; and a secondary coil receiving portion arranged on the other side of the support portion for electrically connecting the secondary coil to the circuit board.

[0009] In the transformer according to the present invention, the upper core includes an upper midfoot protruding in the first direction, and a pair of upper outer legs protruding parallel to the upper midfoot so as to be symmetrical about the upper midfoot, the lower core includes a lower midfoot protruding opposite the upper midfoot, and a pair of lower outer legs protruding parallel to the lower midfoot so as to be symmetrical about the lower midfoot, and the pair of support members may be configured such that each side is in contact with the inner surface of the pair of upper outer legs and the pair of lower outer legs.

[0010] In the transformer according to the present invention, the width of the upper intermediate leg may be greater than the width of the upper outer leg, and the width of the lower intermediate leg may be greater than the width of the lower outer leg.

[0011] In the transformer according to the present invention, the length of the upper intermediate leg and the lower intermediate leg in the second direction may be shorter than the length of the upper outer leg and the lower outer leg.

[0012] In the transformer according to the present invention, the support portion may have a width of 3 mm to 5 mm.

[0013] In the transformer according to the present invention, the support may have a height of 3 mm to 5 mm.

[0014] In the transformer according to the present invention, the terminal pin of the primary coil receiving portion can be inserted into and fixed to the circuit board.

[0015] In the transformer according to the present invention, the terminal pin of the primary coil receiving portion can be inserted and fixed to 55% to 80% of the thickness of the circuit board.

[0016] In the transformer according to the present invention, the terminal pin of the primary coil receiving portion may have a cross-sectional shape in the first direction that is a “T” shape.

[0017] In the transformer according to the present invention, the terminal pin of the primary coil receiving portion may have a cross-sectional shape in the second direction in the shape of the letter “ㅁ”.

[0018] In the transformer according to the present invention, the bottom surface of the lower core and the bottom surface of the circuit board can be arranged on the same line in the second direction.

[0019] In the transformer according to the present invention, the secondary coil may be arranged above and below the primary coil in the first direction.

[0020] The transformer according to the present invention has a thin thickness and can firmly fix the coil inside.

[0021] The area to be bonded to the printed circuit board according to the present invention is large, so it can be stably fixed.

[0022] Figure 1 is a perspective view of a transformer according to the present invention.

[0023] Figure 2 is an exploded perspective view of a transformer according to the present invention.

[0024] Figure 3 is a plan view of the lower bobbin in the transformer according to the present invention.

[0025] Figure 4 is a side view of the lower bobbin in the transformer according to the present invention.

[0026] Figure 5 is a plan view of the upper bobbin in the transformer according to the present invention.

[0027] Fig. 6 is an example diagram for combining a transformer according to the present invention, and is an example diagram of placing a lower core on a lower bobbin.

[0028] Fig. 7 is an example diagram for combining a transformer according to the present invention, and is an example diagram in which a coil is arranged in the state of Fig. 6.

[0029] Fig. 8 is an example diagram for combining a transformer according to the present invention, and is an example diagram of arranging the upper bobbin in the state of Fig. 7.

[0030] Fig. 9 is an example diagram for combining a transformer according to the present invention, and is an example diagram in which the upper core is placed in the state of Fig. 8.

[0031] Figure 10 is a left side view of a transformer according to the present invention.

[0032] Fig. 11 is an exemplary drawing showing the shape of a terminal pin inserted into a primary coil receiving portion in a transformer according to the present invention.

[0033] Figure 12 is an exemplary diagram showing a state in which a transformer according to the present invention is mounted on a printed circuit board.

[0034] Fig. 13 is a cross-sectional view taken along line A-A' of Fig. 9.

[0035] With respect to the embodiments of the present invention disclosed in the text, specific structural and functional descriptions are merely illustrative for the purpose of explaining the embodiments of the present invention, and the embodiments of the present invention may be implemented in various forms and should not be construed as being limited to the embodiments described in the text.

[0036] The present invention is susceptible to various modifications and takes various forms. Specific embodiments are illustrated in the drawings and described in detail herein. However, this is not intended to limit the present invention to specific disclosed forms, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0037] While terms like "first" and "second" may be used to describe various components, these 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 first component could be referred to as a "second component," and similarly, a second component could also be referred to as a "first component."

[0038] 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 there may also be other components in between. Conversely, when a component is referred to as being "directly connected" or "directly connected" to another component, it should be understood that there are no other components in between. Other expressions that describe the relationship between components, such as "between" and "directly between" or "adjacent to" and "directly adjacent to", should be interpreted similarly. Similarly, "disposed on" can mean disposed directly on the surface of another component or disposed above the surface by a distance.

[0039] 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 "comprises" or "has" indicate the presence of a disclosed feature, number, step, operation, component, part, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0040] 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 to have a meaning consistent with their meaning in the context of the relevant technology, and shall not be construed in an idealized or overly formal sense unless explicitly defined herein.

[0041] Meanwhile, if a particular embodiment can be implemented differently, the functions or operations specified within a particular block may occur in a different order than specified in the flowchart. For example, two consecutive blocks may actually be performed substantially simultaneously, or, depending on the related functions or operations, the blocks may be performed in reverse order.

[0042] Hereinafter, a transformer according to the present invention will be described with reference to the attached drawings. For convenience, the transformer will be described using the Cartesian coordinate system (x-axis, y-axis, z-axis), but it is obvious that the transformer can also be described using other coordinate systems. In addition, according to the Cartesian coordinate system, the x-axis, y-axis, and z-axis are orthogonal to each other, but the embodiment is not limited thereto. That is, the x-axis, y-axis, and z-axis may also intersect each other.

[0043] Fig. 1 is a perspective view of a transformer according to the present invention, and Fig. 2 is an exploded perspective view of the transformer illustrated in Fig. 1 according to the present invention.

[0044] A transformer (1000) according to the present invention comprises a bobbin (200) that supports a coil (illustrated in the drawing below) within a core portion (100).

[0045] The core portion (100) may include an upper core (110) and a lower core (120). The upper core (110) may include a first upper core (110A) and a second upper core (110B) that are connected to each other, and the lower core (120) may include a first lower core (120A) and a second lower core (120B) that are connected to each other. The first upper core (110A) and the second upper core (110B) may be defined as a first core, and the first lower core (120A) and the second lower core (120B) may be defined as a second core. The upper core (110) and the lower core (120) may be divided in the z-axis direction (the first direction or the height direction), and the upper core (110) and the lower core (120) may be combined to form one core portion (100).

[0046] At this time, the upper core (110) is a core located farthest from the upper surface of the printed circuit board to be described later in the first direction (height direction), and the lower core (120) can be defined as a core located closest to the upper surface of the printed circuit board in the first direction (height direction). The upper core (110) and the lower core (120) may have shapes that are symmetrical with respect to each other in the upper and lower directions, that is, in the first direction (height direction), or may have asymmetric shapes. However, in the following description, it is assumed that they have shapes that are symmetrical with respect to each other in the upper and lower directions for convenience of explanation. This shows one embodiment, and the technical features of the present invention can be equally applied to the upper core and the lower core configured as one body, and it will go without saying that such a configuration does not limit the configuration of the present invention.

[0047] The upper core (110) and the lower core (120) can each be divided into a plurality of segment cores. That is, as shown in the drawings below, the upper core (110) can be divided into segments as a first core in the y-axis direction (the second direction or longitudinal direction), and the lower core (120) can be divided into segments as a second core in the y-axis direction (the second direction or longitudinal direction). At this time, the lengths of the first core and the second core in the y-axis direction can be the same. Here, the concept of the y-axis length of each core being 'the same' is considered, and in consideration of the tolerance occurring in the process of forming, processing, etc. of each core, when the deviation of the y-axis length between each core is less than 1%, they can be considered to be included in the same category. Accordingly, the lengths of the first upper core (110A), the second upper core (110B), the first lower core (120A), and the second lower core (120B) in the y-axis direction are the same, and at this time, the allowable deviations of the y-axis direction lengths may be less than 1% from each other.

[0048] The first upper core (110A) is symmetrical with the first lower core (120A) in the z-axis direction, and the second upper core (110B) is symmetrical with the second lower core (120B) in the z-axis direction. For example, the first upper core (110A) may include a first upper midfoot (110CL) protruding from a flat body toward the first lower core (120A), and a pair of first upper outer feet (110OL1, 110OL2) protruding toward the first lower core (120A) in parallel with the first upper midfoot (110CL) so as to be symmetrical with respect to the first upper midfoot (110CL). The first lower core (120A) has a first lower intermediate leg (120CL) protruding upward from a flat body where the first upper core (110A) is located, and a pair of first lower outer legs (120OL1, 120OL2) protruding toward the first upper core (110A) in parallel with the second upper intermediate leg (120CL) so as to be symmetrical about the second lower intermediate leg (120CL). Each intermediate leg of the upper core and the lower core may be formed in a shape having a wider width and shorter length than the pair of upper outer legs and the pair of lower outer legs on either side. Although not specifically illustrated, the second upper core (110B) may have the same shape as the first upper core (110A), and the second lower core (120B) may have the same shape as the first lower core (120A), so that a detailed description thereof will be omitted. FIGS. 3 to 5 are exemplary views showing a bobbin in a transformer according to the present invention. FIG. 3 is a plan view of a lower bobbin in a transformer according to the present invention, FIG. 4 is a side view of a lower bobbin in a transformer according to the present invention, and FIG. 5 is a plan view of an upper bobbin in a transformer according to the present invention.

[0049] Figures 6 to 9 are exemplary diagrams showing the coupling process of a transformer according to the present invention.

[0050] The bobbin (200) comprises a lower bobbin (200A) illustrated in FIGS. 3 and 4 and first and second upper bobbins (200B, 200C) illustrated in FIG. 5. That is, a first cover (210B) of a first upper bobbin (200B) is arranged on the upper portion of a primary coil receiving portion (210A) of the lower bobbin (200A) and is coupled with the primary coil receiving portion (210A). In addition, a second cover (220B) of a second upper bobbin (200C) is arranged on the upper portion of a secondary coil receiving portion (220A) of the lower bobbin (200A) and is coupled with the secondary coil receiving portion (220A).

[0051] The lower bobbin (200A) comprises a primary coil receiving portion (210A) arranged on one side of a pair of supporting portions (230A, 230B) forming the supporting portion (230) and a secondary coil receiving portion (220A) arranged at a position symmetrical to the primary coil receiving portion (210A) with the supporting portions (230A, 230B) as the center. The supporting portions (230A, 230B) may have a width of 3 mm to 5 mm and a height of 3 mm to 5 mm. This is one embodiment, and the size may be changed to correspond to the size of the core and bobbin, which change according to the capacity of the transformer, and the two supporting portions may have different width and height values.

[0052] The support portions (230A, 230B) extend in the y-axis direction intersecting the z-axis direction, centered on the through-holes in which the lower surface of the upper core (110) and the upper surface of the lower core (120) are open in the z-axis direction, and serve to support the coil portions (310, 320) within the core portion (100).

[0053] The primary coil receiving portion (210A) is arranged on one side of the support portion (230) to receive the primary coil (310), and has a 1-2 terminal pin (211B) electrically connected to the starting end (310s) of the primary coil and a 1-1 terminal pin (211A) electrically connected to the ending end (310e) of the primary coil.

[0054] The secondary coil receiving portion (220A) is positioned symmetrically to the primary coil receiving portion (210A) to receive the secondary coil (321, 322) and has a plurality of connection terminals (221, 222, 223, 224) formed on one side for electrical connection to the circuit board.

[0055] The first upper bobbin (200B) illustrated in FIG. 5 is positioned above the primary coil receiving portion (210A) in the z-axis direction, i.e., in the height direction, so as to firmly fix the primary coil (310). It can be coupled to the primary coil receiving portion (210A) in various ways, such as by fitting. The second upper bobbin (200C) illustrated in FIG. 5 can also be coupled to the upper portion of the secondary coil receiving portion (220A) in the z-axis direction, i.e., in the height direction, so as to firmly fix the primary coil (310).

[0056] As illustrated in Fig. 6, the lower bobbin (200A) is positioned above the lower core (120). At this time, each support member (230A, 230B) is arranged in such a manner that it is in close contact with the inner surface of each outer leg (120OL1, 120OL2) of the first and second lower cores (120A, 120B). Specifically, the outer surface of the support member (230A) may be arranged in such a manner that it is in close contact with the inner surface of the outer leg (120OL1), and the outer surface of the support member (230B) may be arranged in such a manner that it is in close contact with the inner surface of the outer leg (120OL2).

[0057] In this state, the coil part (300) is connected as shown in Fig. 7. First, the lower secondary coil (321) among the secondary coils (320) is placed. The lower secondary coil (321) is connected at its starting point (321S) to the rightmost connection terminal (224) of the secondary coil receiving part (220A) in the y-axis direction from the starting point (321S) while contacting the right support part (230B) of the lower bobbin (200A), moves in the x-axis direction until it passes the middle foot (120CL) of the lower core (120), and then extends in the y-axis direction again after passing the middle foot (120CL). Accordingly, the end part (321E) of the lower secondary coil (321) is connected to the middle connection terminal (222) of the secondary coil receiving part (220A).

[0058] The primary coil (310) is arranged above the lower secondary coil (321), i.e., above in the z-axis direction. That is, at least a portion of the primary coil (310) can vertically overlap at least a portion of the lower secondary coil (321). The starting end (310s) of the primary coil (310) is electrically connected to the 1-2 terminal pin (211B). Then, after wrapping around the middle leg (120CL) of the lower core (120) several times, the terminal end (310e) of the primary coil is arranged to be electrically connected to the 1-1 terminal pin (211A).

[0059] The upper secondary coil (322) is arranged above the primary coil (310). That is, at least a portion of the upper secondary coil (322) can vertically overlap at least a portion of the primary coil (310). The starting portion (322S) of the upper secondary coil (322) is connected to the connection terminal (223) of the secondary coil receiving portion (220A). The upper secondary coil (322) extends from the starting portion (322S) in the y-axis direction through the middle foot (120CL) of the lower core (120) to the primary coil receiving portion (210A), and then extends in the y-axis direction while contacting the left support portion (230A) of the lower bobbin (200A). Accordingly, the terminal portion (322E) of the upper secondary coil (322) is connected to the leftmost connection terminal (221) of the secondary coil receiving portion (220A). In this state, as shown in FIG. 8, the first cover (210B) of the first upper bobbin (200B) is placed and coupled to the upper portion of the primary coil receiving portion (210A), and the second cover (220B) of the second upper bobbin (200C) is placed and coupled to the upper portion of the secondary coil receiving portion (220A). In this state, as shown in FIG. 9, the upper core (110), that is, the first upper core (110A) and the second upper core (110B), are coupled to the lower core (120).

[0060] Fig. 10 is a left side view of a transformer according to the present invention, Fig. 11 is an exemplary view showing the shape of a terminal pin inserted into a primary coil receiving portion in a transformer according to the present invention, and Fig. 12 is an exemplary view showing a state in which a transformer according to the present invention is mounted on a printed circuit board.

[0061] It can be seen that the upper cores (110A, 110B) are coupled to the upper portion of the lower cores (120A, 120B), the first cover (210B) of the first upper bobbin (200B) is coupled to the upper portion of the primary coil receiving portion (210A), and the second cover (220B) of the second upper bobbin (200C) is coupled to the upper portion of the secondary coil receiving portion (220A). Terminal pins (211B, 211A) electrically connected to the starting end (310s) and the ending end (310e) of the primary coil (310) are respectively arranged on both sides of the primary coil receiving portion (210A). The secondary coil receiving portion (220A) is provided with a plurality of connection terminals (221, 222, 223, 224) for electrically connecting the starting portion (321S, 322S) and the ending portion (321E, 322E) of the secondary coil, and a plurality of terminal pins (212) are arranged in each connection terminal (221, 222, 223, 224) and are inserted into a printed circuit board (2000) and electrically connected to the connection terminal (221, 222, 223, 224) and predetermined components of the circuit board.

[0062] The transformer (1000) is connected to the printed circuit board (2000) by arranging the back surface of the lower core (120) in the same line parallel to the y-axis direction in correspondence with the upper surface of the printed circuit board (2000).

[0063] The terminal pins (211A, 211B) arranged in the primary coil receiving portion (210A) and the terminal pins (212) arranged in the secondary coil receiving portion (220A) are inserted into and fixed to the printed circuit board (2000). At this time, the length at which the terminal pins (211A, 211B, 212) are inserted into the printed circuit board (2000) may be a thickness (T2) of about 55% to 80% of the thickness (T1) of the printed circuit board (2000), and the terminal pins (211A, 211B, 212) may be inserted into and fixed to the printed circuit board (2000).

[0064] Meanwhile, each terminal pin (211A, 211B) of the primary coil receiving portion (210A) is composed of a horizontal portion (211-S) extending in the x-axis direction of the transformer, i.e., the width direction, and a vertical portion (211-V) extending downward in the z-axis direction, i.e., the height direction of the transformer, from the horizontal portion (211-S), and the cross-section in the z-axis direction may have a "T" shape, and the cross-section in the y-axis direction may have a square "ㅁ" shape. Due to this shape, the contact area with the printed circuit board can be widened, thereby increasing the bonding strength.

[0065] Fig. 13 is a cross-sectional view taken along line A-A' of Fig. 9. As shown, the upper core (110) is placed on the lower core (120), and the two supporting portions (230A, 230B) of the lower bobbin (200A) are placed in close contact with one outer leg (110OL1, 120OL1) and the other outer leg (110OL2, 120OL2) of each core. That is, the first supporting portion (230A) is placed in close contact with the inner surface (111) of the first outer leg (110OL1) of the first upper core (110A) and the inner surface (121) of the first outer leg (120OL1) of the first lower core (120A). The second support member (230B) is arranged in close contact with the inner surface (112) of the second outer leg (110OL2) of the first upper core (110A) and the inner surface (122) of the second outer leg (120OL2) of the first lower core (120A). At this time, it can be seen that the lower secondary coil (321) is arranged at the bottom, the first coil (310) is arranged thereon, and the upper secondary coil (322) is arranged thereon sequentially. At this time, the first support member (230A) is arranged in contact with the coil (322) close to the end of the lower secondary coil (321), the coil close to the end of the primary coil (310), the inner surface (111) of the first outer leg (110OL1) of the upper core, and the inner surface (121) of the first outer leg (120OL1) of the lower core. The second support member (230B) is arranged to be in contact with the coil (321) close to the beginning of the lower secondary coil (321), the coil close to the beginning of the primary coil (310), the inner surface (112) of the second outer leg (110OL2) of the upper core, and the inner surface (122) of the second outer leg (120OL2) of the lower core. Accordingly, the primary coil (310) and the secondary coil (320) can be firmly fixed to the core member (100) by the first support member (230A) and the second support member (230B) having a thickness of, for example, 3 mm to 8 mm, as in "T".

[0066] Each of the first support portion (230A) and the second support portion (230B) may include a first region (A1), a second region (A2), and a third region (A3) which are divided along the z-axis direction, as illustrated in FIG. 13. The first region (A1), the second region (A2), and the third region (A3) may be arranged in a space formed between the upper core (110) and the lower core (120). The first region (A1) may overlap the upper secondary coil (322) in the x-axis direction (the third direction or the width direction). In some embodiments, the first region (A1) may not overlap the primary coil (310) and the lower secondary coil (321) in the x-axis direction. The second region (A2) may overlap the primary coil (310) in the x-axis direction. And according to an embodiment, the second region (A2) may not overlap with the upper secondary coil (322) and the lower secondary coil (321) in the x-axis direction. The third region (A3) may overlap with the lower secondary coil (321) in the x-axis direction. And according to an embodiment, the third region (A3) may not overlap with the upper secondary coil (322) and the primary coil (310) in the x-axis direction.

[0067] Although the present invention has been described above with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

[0068] The mode for carrying out the invention has been sufficiently described in the above-mentioned “Best mode for carrying out the invention.”

[0069] The transformer according to the embodiment can be used in a power supply device of an electronic device, etc.

Claims

1. A core section having an upper core and a lower core arranged opposite to the upper core in a first direction; A coil section including a primary coil and a secondary coil arranged in an insulated manner from the primary coil: and Including a bobbin that supports the coil section within the core section, The above bobbin, A pair of support parts extending in a second direction intersecting the first direction, each of which is centered on a through hole having an open portion facing the lower surface of the upper core and the upper surface of the lower core in the first direction, and which support the coil part within the core part; A primary coil receiving portion having a terminal pin coupled thereto, which is arranged on one side of the support portion and electrically connects the primary coil to a circuit board; and A transformer including a secondary coil receiving portion arranged on the other side of the support portion and electrically connecting the secondary coil to the circuit board.

2. In paragraph 1, The upper core includes an upper midfoot protruding in the first direction and a pair of upper outer feet protruding parallel to the upper midfoot so as to be symmetrical about the upper midfoot, The lower core includes a lower midfoot protruding to face the upper midfoot, and a pair of lower outer legs protruding parallel to the lower midfoot so as to be symmetrical about the lower midfoot, A transformer in which each of the pair of supports is in contact with the inner surface of each of the pair of upper outer legs and the pair of lower outer legs.

3. A transformer in the second paragraph, wherein the width of the upper intermediate leg is greater than the width of the upper outer leg, and the width of the lower intermediate leg is greater than the width of the lower outer leg.

4. In the second paragraph, a transformer in which the length of the upper intermediate leg and the lower intermediate leg in the second direction is shorter than the length of the upper outer leg and the lower outer leg.

5. A transformer in the first paragraph, wherein the support has a width of 3 mm to 5 mm.

6. In the fifth paragraph, a transformer having a height of 3 mm to 5 mm.

7. A transformer in which the terminal pin of the primary coil receiving portion in the first paragraph is inserted and fixed to the circuit board.

8. A transformer in which, in the 7th paragraph, the terminal pin of the primary coil receiving portion is inserted and fixed by 55% to 80% of the thickness of the circuit board.

9. In the 8th paragraph, a transformer in which the terminal pin of the primary coil receiving portion has a cross-sectional shape in the first direction that has a “T” shape.

10. In the 9th paragraph, the terminal pin of the primary coil receiving portion is a transformer having a cross-sectional shape in the second direction in the shape of the letter “ㅁ”.

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