KR20230002189A - Magnetic component and circuit board having the same - Google Patents

Abstract

A transformer according to one embodiment of the present invention comprises: a core part; and a first coil part and a second coil part having at least one part accommodated in the core part, wherein at least one among the first coil part and the second coil part enables a plurality of conductive lines to cross each other in a specific area to reduce an inductance deviation between the conductive lines. Therefore, the present invention is capable of minimizing a difference in length of the conductive line.

Description

Magnetic element and circuit board including the same {MAGNETIC COMPONENT AND CIRCUIT BOARD HAVING THE SAME}

The present invention relates to a magnetic element capable of reducing heat generation due to an inductance variation according to a configuration of a coil and a circuit board including the magnetic element.

Various coil parts such as transformers and line filters are mounted in power supplies of electronic devices.

Transformers (transformers) may be included in electronic devices for various purposes. For example, a transformer can be used to perform the function of transferring energy from one circuit to another. In addition, the transformer may be used to perform a step-up or step-down function that changes the size of the voltage. In addition, since only inductive coupling (coupling) is made between the primary and secondary windings, the transformer, which has the feature that no DC path is directly formed, may be used for the purpose of blocking DC and passing AC, or for isolating between two circuits. .

1 is an exploded perspective view showing an example of a typical transformer configuration.

Referring to FIG. 1, a general slim transformer 10 includes a core portion including an upper core 11 and a lower core 12, and a secondary coil 13 and a primary coil (between 11 and 12) 14). The secondary coil 13 is composed of a plurality of conductive metal plates, and the primary coil 14 usually has a form in which a conductive wire is wound. Depending on the configuration, a bobbin (not shown) may be disposed between the upper core 11 and the lower core 12 .

In the transformer shown in FIG. 1, the primary coil and the secondary coil are overlapped in the vertical direction. When a conductive wire is applied to the secondary coil instead of a conductive metal plate, the primary coil and the secondary coil overlap each other in the horizontal direction. can be placed.

By the way, when applying a conductive wire to the secondary coil, since they must be arranged side by side on a plane for slimming, in forming a turn around the midfoot of the core part, the inner conductive wire closest to the midfoot has the shortest length, and the farthest outer The length of the conductive line is the longest, resulting in inductance deviation. This inductance deviation causes current drift, and the current drift causes severe heat generation again.

A technical problem to be achieved by the present invention is to provide a slim transformer capable of reducing heat generation and a circuit board using the same.

In particular, the present invention is to provide a transformer capable of preventing heat generation due to inductance variation due to a difference in length of coils composed of conductive wires, and a circuit board using the same.

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

A transformer according to an embodiment includes a core portion including an upper core and a lower core; and a bobbin at least partially disposed between the upper core and the lower core. and a first coil part and a second coil part, at least partially disposed on the bobbin, wherein the bobbin includes: a through hole formed in a central portion; a first part disposed on one side of the bobbin in a first direction from the through hole; and a second part disposed on the other side of the through hole opposite to the first part, wherein at least one of the first coil part and the second coil part includes a plurality of conductive wires disposed around the through hole. Including, one side of the plurality of conductive lines extends to be disposed on the second portion, the other side of the plurality of conductive lines extends to have both ends disposed on the first portion, and the first of the plurality of conductive lines The first conductive line and the second conductive line may include an overlapping portion at least partially overlapping the second portion, and the bobbin may have an opening formed in the second portion to expose at least a portion of the overlapping portion.

For example, the bobbin may include an upper plate; lower plate; and a sidewall portion disposed between the upper plate and the lower plate, and the opening may be formed in at least one of the upper plate and the lower plate.

For example, the opening may have a planar shape of any one of a semicircular shape, a circular shape, a track shape, and a polygonal shape.

For example, the overlapping portion may include a plurality of regions corresponding to each overlapping combination pair among the plurality of conductive lines, and the opening may expose at least a portion of the plurality of regions.

For example, the planar area of the opening may correspond to 50% to 90% of the sum of the planar areas of the plurality of regions.

For example, the first conductive line and the second conductive line among the plurality of conductive lines may extend parallel to each other along the first direction in the central portion.

For example, the first conductive line and the second conductive line may not overlap each other in the central portion.

For example, the first conductive line and the second conductive line may have a symmetrical shape along the first direction with respect to the through hole.

For example, the plurality of conductive lines may include a third conductive line forming a turn outward of the first conductive line on a plane; and a fourth conductive line forming a turn outside the second conductive line on a plane.

For example, the third conductive line may form a turn parallel to the first conductive line, and the fourth conductive line may form a turn parallel to the second conductive line.

For example, at least one of the first coil unit and the second coil unit further includes a plurality of terminal pins disposed side by side in the first part along a second direction, and among the plurality of terminal pins, a ground It may further include a shorting unit for shorting a plurality of corresponding terminal pins to each other.

A circuit board according to an embodiment includes a substrate; and a transformer disposed on the substrate, wherein the transformer includes: a core portion including an upper core and a lower core; and a bobbin at least partially disposed between the upper core and the lower core. and a first coil part and a second coil part, at least partially disposed on the bobbin, wherein the bobbin includes: a through hole formed in a central portion; a first part disposed on one side of the bobbin in a first direction from the through hole; and a second part disposed on the other side of the through hole opposite to the first part, wherein at least one of the first coil part and the second coil part includes a plurality of conductive wires disposed around the through hole. Including, one side of the plurality of conductive lines extends to be disposed on the second portion, the other side of the plurality of conductive lines extends to have both ends disposed on the first portion, and the first of the plurality of conductive lines The first conductive line and the second conductive line may include an overlapping portion at least partially overlapping the second portion, and the bobbin may have an opening formed in the second portion to expose at least a portion of the overlapping portion.

In the transformer according to the embodiment, a plurality of conductive lines constituting a coil may cross each other in one area to minimize a difference in length of the conductive lines.

In addition, inductance deviation between conductive lines constituting the same turn in parallel is improved through shorting of terminal pins, thereby reducing heat generation.

In addition, slimming is possible because the bobbin has an opening in the region where the intersection between the conductive lines occurs.

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

1 is an exploded perspective view showing an example of a configuration of a general slim type transformer.
2A is a plan view of a transformer according to an exemplary embodiment.
2B is a plan view illustrating a form in which a core portion is removed from a transformer according to an exemplary embodiment.
FIG. 2C is a cross-sectional view of a transformer according to an exemplary embodiment taken along the line AA′ of FIG. 2A.
3 is a plan view illustrating an example of a configuration of a second coil unit according to an exemplary embodiment.
4A shows a pin map of a second coil unit according to an embodiment, and FIG. 4B is a circuit diagram of a transformer according to an embodiment.
5 is a plan view illustrating an example of a configuration of a second coil unit according to a comparative example.
6 shows current deviations of a transformer according to an embodiment and a transformer according to a comparative example.
7 shows an example of a heat distribution form of a transformer according to an embodiment and a transformer according to a comparative example.
8 is a plan view illustrating an example of a configuration of a second coil unit according to another embodiment.
9 shows an example of a heat distribution form of a transformer according to one embodiment and a transformer according to another embodiment.
10 is a view for explaining a form in which conductive lines overlap in a second part of a second coil part according to an exemplary embodiment.
11A is an example of a plan view of the second coil unit according to another embodiment, FIG. 11B is a side view of the second coil unit shown in FIG. 11A, and FIG. 11C is another plan view of the second coil unit according to another embodiment. An example is shown respectively.

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

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

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

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

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

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

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

FIG. 2A is a plan view of a transformer according to an embodiment, FIG. 2B is a plan view showing a form in which a core is removed from a transformer according to an embodiment, and FIG. 2C is a plan view of a transformer according to an embodiment taken along line A-A' of FIG. 2A. It is a cross-sectional view showing a cross section cut along.

Referring to FIGS. 2A to 2C , the transformer 100 according to an exemplary embodiment may include core parts 111 and 112 , a first coil part 120 and a second coil part 130 . Hereinafter, each component will be described in detail.

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

Each of the upper core 111 and the lower core 112 may include a flat body portion and a plurality of leg portions protruding from the body portion in a thickness direction (ie, three-axis direction) and extending along a predetermined direction. The plurality of leg parts extend along one axis (here, axis 1) on a plane and are spaced apart from each other along the direction of the other axis (here, axis 2), and one midfoot (CL) disposed between the two outer legs. ) may be included.

When the upper core 111 and the lower core 112 are coupled up and down, each of the outer and midfoot of the upper core 111 faces the outer or midfoot corresponding to each other of the lower core 112 . At this time, a gap of a predetermined distance (eg, 10 to 100 um, but is not necessarily limited thereto) may be formed between at least some of the outer or midfoot pairs facing each other.

In addition, the core parts 111 and 112 may include a magnetic material such as iron or ferrite, but are not necessarily limited thereto.

The first coil unit 120 is wound so as to form a plurality of turns around the first bobbin B1 having the first through hole CH1 in the center and the first through hole CH1 in the accommodating space of the first bobbin. A first coil C1 may be included.

The second coil unit 130 is centered around the second bobbin B2 having the second through hole (CH2 in FIG. 3) at the center and the second through hole CH2 in the accommodating space of the second bobbin B2. A second coil C2 arranged to form a turn may be included. Here, at least a part of the first coil unit 120 may be disposed in the second through hole CH2. Accordingly, at least a portion of the first coil unit 120 and the second coil unit 130 may overlap along the first axial direction and the second axial direction. Also, the accommodating space of the second bobbin B2 may be defined by the upper plate TP, the lower plate BP, and the side wall portion SW disposed between the upper plate TP and the lower plate BP.

The first coil C1 and the second coil C2 may be multiple windings in which a rigid conductor metal, for example, a copper conductive wire is wound several times in a spiral or planar spiral, but is not necessarily limited thereto. For example, the first coil C1 may be an enamel wire wrapped with fiber yarn (USTC wire), a Litz wire, a triple insulated wire (TIW), or the like.

Depending on the embodiment, the first coil unit 120 may correspond to the primary coil of the transformer 100, and the second coil unit 130 may correspond to the secondary coil of the transformer 100, but must be It is not limited to this.

In addition, the diameter of the second coil (C2) may be 0.7 to 0.9 times the height of the second bobbin (B2) in the 3-axis direction, but is not necessarily limited thereto.

A more detailed configuration of the second coil unit will be described with reference to FIG. 3 .

3 is a plan view illustrating an example of a configuration of a second coil unit according to an exemplary embodiment.

In FIG. 3 , the upper plate TP of the second bobbin B2 is removed for convenience of description.

The second coil unit 130A shown in FIG. 3 includes a second bobbin B2, a second coil C2, and a plurality of terminal pins T1, T2, T3, T4, T5, T6, T7, and T8. can do.

The second bobbin B2 includes a first part 1P located at one side of the central part CP, the central part CP or the second through hole CH2 in the axial direction, and the central part CP or the second through hole. (CH2) may include a second portion (2P) located on the other side opposite to the first portion (1P) in one axis direction.

A second through hole CH2 may be disposed in the central portion CP, and a plurality of terminal pins T1, T2, T3, T4, T5, T6, T7, and T8 along the 2-axis direction may be disposed in the first portion 1P. ) can be placed side by side.

The second coil C2 may include a plurality of conductive lines L1, L2, L3, and L4.

Both ends of the plurality of conductive lines (L1, L2, L3, L4) are electrically connected to one of the plurality of terminal pins (T1, T2, T3, T4, T5, T6, T7, T8), respectively, Each turn may be formed around the second through hole CH2. Therefore, the efficiency of the transformer can be increased by lowering the resistance to the applied current, and the heat generated by the transformer can be suppressed by lowering the heat generated by the resistance.

For example, both ends of the first conductive line L1 are connected to the second terminal pin T2 and the fifth terminal pin T5, and both ends of the third conductive line L3 are connected to the first terminal pin ( T1) and the sixth terminal pin T6 respectively. In addition, both ends of the second conductive line L2 are connected to the fourth terminal pin T4 and the seventh terminal pin T7, respectively, and both ends of the fourth conductive line L4 are connected to the third terminal pin T3. ) and the eighth terminal pin T8, respectively.

Meanwhile, at least a part of the first conductive line L1 and the third conductive line L3 is along the three-axis direction in the second conductive line L2 and the fourth conductive line L4 and the second portion 2P. They can intersect so that they overlap. In addition, the plurality of conductive lines L1 , L2 , L3 , and L4 may be disposed parallel to each other along two axial directions in the central portion CP and extend along one axial direction. In FIG. 3 , the plurality of conductive lines L1 , L2 , L3 , and L4 are shown as not overlapping each other along the 3-axis direction in the central portion CP, but a portion in the 3-axis direction in a region adjacent to the second portion 2P. Overlapping may occur. That is, one side of each of the plurality of conductive lines L1, L2, L3, and L4 may extend to be disposed on the second portion 2P, and the other side may extend to have both ends disposed on the first portion 1P. there is.

Due to the configuration of the second coil unit 130 described above, there is a portion (ie, an overlapping portion) in which the conductive wires constituting the second coil C2 overlap in the second portion 2P, etc., but from the viewpoint of the individual conductive wires Since only one turn is achieved in , the second coil C2 can be regarded as being wound in one layer.

The terminal pin connection state and the crossing in the second part 2P are for inductance matching between parts making the same turn from a circuit point of view. This will be described with reference to FIGS. 4A and 4B.

4A shows a pin map of a second coil unit according to an embodiment, and FIG. 4B is a circuit diagram of a transformer according to an embodiment.

4A and 4B, the first conductive line L1 and the third conductive line L3 are connected in parallel to form a first turn NS2 for the first signal of the secondary coil of the transformer, The second conductive line L2 and the fourth conductive line L4 constitute the second turn portion NS3 for the second signal of the secondary coil. In this case, the first terminal pin T1 and the second terminal pin T2 correspond to input terminals for the first signal, and the fifth terminal pin T5 and the sixth terminal pin T6 correspond to the first signal. Corresponds to the ground. In addition, the seventh terminal pin T7 and the eighth terminal pin T8 correspond to input terminals for the second signal, and the fourth terminal pin T4 and the fifth terminal pin T5 correspond to the second signal. corresponds to the ground. Here, grounds of each signal may be electrically connected to each other to form a so-called Center Tap (CT) structure.

Returning to FIG. 3 again, due to the above-described connection between the conductive wire and the terminal pins, the first conductive line L1 and the third conductive line L3 constituting the first turn portion NS2 are formed in parallel with the second turn portion. The second and fourth conductive lines L2 and L4 constituting NS3 and the second through hole CH2 form a mirror image (symmetrical) shape on a plane along one axis direction. Therefore, since the first turn part NS2 and the second turn part NS3 have substantially the same conductive line configuration, the inductance deviation due to the length difference of the conductive lines is minimized, and through this, heat generation due to current concentration can be reduced. .

Effects of the configuration of the above-described second coil unit 130A will be described in more detail through comparison with comparative examples with reference to FIGS. 5 to 7 .

5 is a plan view illustrating an example of a configuration of a second coil unit according to a comparative example.

Referring to FIG. 5, the second coil unit 130' according to the comparative example has the same configuration of the second bobbin B2 as in the first embodiment, but the plurality of conductive lines L1, L2, L3, and L4 are connected to each other. They are parallel and do not intersect each other so that at least a part overlaps with each other in three axial directions even in the second part 2P. In this case, the first conductive line L1' has the shortest length because it forms the innermost turn, and the fourth conductive line L4' has the longest length because it forms the outermost turn.

6 shows current deviations of a transformer according to an embodiment and a transformer according to a comparative example.

Referring to FIG. 6, graphs are shown at the top and bottom respectively, and in each graph, the vertical axis represents current and the horizontal axis represents time. In addition, the upper graph shows the effective (rms) current of each turn unit in the second coil unit 130A according to an embodiment, and the lower graph shows the rms current (rms) of each turn unit in the second coil unit 130' according to the comparative example. rms) represents the current.

First, as shown in the upper graph, since the second coil unit 130A according to an exemplary embodiment has substantially the same conductive line configuration between turns, the current difference between the first turn unit NS2 and the second turn unit NS3 is It is only 0.39A.

Unlike this, as shown in the upper graph, the second coil unit 130' according to the comparative example has a different conductive wire configuration between the turns, so that the difference in current between the first turn unit NS2 and the second turn unit NS3 is It reached 1.56A.

This current bias causes a difference in heat generation. This will be described with reference to FIG. 7 .

7 shows an example of a heat distribution form of a transformer according to an embodiment and a transformer according to a comparative example.

Referring to FIG. 7 , an upper image is a thermal imaging camera image captured during operation of a transformer to which a second coil unit 130A according to an embodiment is applied, and a temperature in a region 610 corresponding to the first portion 1P. It can be seen that is relatively uniform, and the maximum temperature was measured at about 68 degrees.

The lower image is a transformer to which the second coil unit 130' according to the comparative example is applied, and current is concentrated in a specific area 620, so heat is concentrated, and the maximum temperature is 70.7 degrees, which is higher than that of one embodiment.

The transformer according to the embodiment described so far has an effect of reducing inductance deviation because each of the conductive lines constituting the second coil C2 of the second coil unit 130 has a symmetrical shape for each signal. However, as shown in FIG. 3, even if the turns corresponding to the same signal, the lengths of each conductive line connected in parallel are different. For example, in the case of the first conductive line L1 and the third conductive line L3 constituting the first turn portion NS2, the first conductive line L1 is positioned inside the third conductive line L3. Therefore, it is relatively short in length. Therefore, in order to minimize such a conductive wire deviation, another embodiment of the present invention proposes to short the terminal pins to each other to reduce the input inductance deviation generated from the terminal pins in the transformer. The configuration of the second coil unit for this will be described with reference to FIG. 8 .

8 is a plan view illustrating an example of a configuration of a second coil unit according to another embodiment.

Since the configuration of the second coil unit 130B according to another embodiment shown in FIG. 8 is the same as the configuration of the second coil unit 130A according to the embodiment except for the short circuit parts SP1, SPC, and SP2, Redundant descriptions will be omitted.

Referring to FIG. 8 , the first terminal pin T1 and the second terminal pin T2 corresponding to input terminals of the first signal may be short-circuited through the first short circuit SP1. In addition, the seventh terminal pin T7 and the eighth terminal pin T8 corresponding to input terminals of the second signal may be short-circuited through the second short circuit SP2. In addition, the third to sixth terminal pins T3 , T4 , T5 , and T6 corresponding to the ground of the center tap configuration may be short-circuited through the center short circuit SPC.

Here, each of the short-circuit parts SP1, SP2, and SPC may be implemented through soldering, but this is illustrative and not necessarily limited thereto, and is not limited to any method as long as short-circuiting between terminal pins is possible. For example, each of the shorting parts SP1, SP2, and SPC may be implemented through a conductor clip, a conductor pin, or a combination thereof and soldering.

In FIG. 8, the center short-circuit (SPC) is integrally configured to short-circuit all of the third to sixth terminal pins (T3, T4, T5, and T6), but according to another aspect, the center short-circuit (SPC) is A first center short-circuit (not shown) short-circuits the third terminal pin T3 and the fourth terminal pin T4, and a second center short-circuit short-circuits the fifth terminal pin T5 and the sixth terminal pin T6. It may also consist of a part (not shown). In this case, the first center short-circuit (not shown) and the second center short-circuit (not shown) may not be electrically connected within the transformer.

Effects of the second coil unit 130B according to another embodiment will be described with reference to FIG. 9 .

9 shows an example of a heat distribution form of a transformer according to one embodiment and a transformer according to another embodiment.

Referring to FIG. 9 , an upper image is a thermal imaging camera image captured during operation of a transformer to which a second coil unit 130A according to an embodiment is applied, and each terminal corresponding to the center tap is not shorted, so that the vicinity of the center tap ( 910), it can be seen that the heat is relatively concentrated.

The lower image is a transformer to which the second coil unit 130B according to another embodiment is applied, and it can be seen that heat generation is improved even in the vicinity 920 of the center tap. In particular, in the temperature, it is measured at a maximum of 69 degrees in the upper image, but in the lower image, it can be seen that the fever is reduced by about 5.5 degrees to a maximum of 63.5 degrees.

The experimental results for inductance are shown in Table 1 below.

division in part 2 cross in part 2 no intersection conductive line 2nd Ls [uH] conductive line 2nd Ls [uH] paragraph
doesn't exist L3 2.78 L3 2.81 L1 2.71 L1 2.62 △ 0.07 △ 0.19 L4 2.78 L4 2.74 L2 2.71 L2 2.6 △ 0.07 △ 0.14 1st center section &
2nd center section L3 2.71 L3 2.65 L1 2.7 L1 2.62 △ 0.01 △ 0.03 L4 2.71 L4 2.66 L2 2.71 L2 2.64 △ 0 △ 0.02 Integral center short L3 2.71 L3 2.64 L1 2.7 L1 2.62 △ 0.01 △ 0.02 L4 2.71 L4 2.66 L2 2.71 L2 2.65 △ 0 △ 0.01

The experiment, the results of which are shown in Table 1, was conducted in a total of six cases depending on whether there was an intersection between conductive lines in the second part (2P) of the second bobbin (B2) and the configuration of the short circuit, and the measured values were measured for each conductive line ( The inductance of L1 to L4) was measured.

That is, in the classification of Table 1, “intersection in the second part” means a configuration in which the intersection between the conductive lines occurs in the second part 2P of the second bobbin B2 as shown in FIG. 3 or FIG. 8, and “the second part “No intersection in the section” may mean a configuration as shown in FIG. 5 .

In addition, “no short circuit” means a configuration without a short circuit as shown in FIG. 3 or 5, and “integral center short circuit” means a short circuit configuration as shown in FIG. 8 . In addition, "first center short-circuit & second center short-circuit" short-circuits the third terminal pin T3 and the fourth terminal pin T4, which are not integrated with the center short-circuit in the configuration of FIG. 8 . It refers to a configuration separated into a first center short-circuiting part (not shown) and a second center short-circuiting part (not shown) shorting the fifth terminal pin T5 and the sixth terminal pin T6.

Referring to Table 1, irrespective of the presence or absence of short circuits, the "intersection in the second part" cases showed a smaller inductance deviation compared to the "no crossing in the second part" cases, through the crossing between the conductive lines in the second part. It can be seen that reducing the length deviation between the conductive lines is effective in resolving the inductance deviation.

In addition, when the short circuit is present, the inductance deviation is significantly lower than when the short circuit is not present, and in the case of the center short circuit, the integrated case shows slightly better performance than the configuration having the first / second center short circuit separately. can

On the other hand, as the intersection between the conductive lines occurs in the second portion 2P of the second bobbin B2, overlapping occurs between the conductive lines in the three-axis direction, so that the height of the sidewall portion SW of the second bobbin B2 increases. Deformation of the second bobbin (B2) in the second part (2P) can be prevented only when the thickness of the conductive wire is secured at least twice. However, due to the securing of the height of the side wall portion SW, the second bobbin B2 becomes thick as a whole, which can increase the overall thickness of the transformer. This will be described with reference to FIG. 10 .

10 is a diagram for explaining a form in which conductive lines overlap in a second part of a second coil part according to an exemplary embodiment. In FIG. 10, for better understanding, the conductive lines L1, L2, L3, and L4 are expressed as solid lines regardless of overlapping.

Referring to FIG. 10 , the second portion 2P of the second coil unit has a plurality of overlapping regions according to overlapping combination pairs between a plurality of conductive lines. For example, in the second portion 2P, a first region A1 in which the third conductive line L3 and the fourth conductive line overlap on a plane, and the first conductive line L1 and the fourth conductive line L4 are formed. The second area A2 overlaps on the plane, the third area A3 overlaps the second conductive line L2 and the third conductive line L3 on the plane, and the first and second conductive lines overlap on the plane. An overlapping fourth area A4 occurs.

In these areas A1, A2, A3, and A4, a larger accommodating space is required in the three-axis direction than the other areas.

Therefore, in another embodiment of the present invention, an opening is formed in at least one of the upper plate (TP) and the lower plate (BP) in the region corresponding to the second portion (2P) of the second bobbin (B2) to open the second bobbin. It is suggested to prevent the thickness increase.

11A is an example of a plan view of a second coil unit according to another embodiment, FIG. 11B is a side view of the second coil unit shown in FIG. 11A as viewed in the direction of the arrow at the top of FIG. 11A, and FIG. Another example of a plan view of the second coil unit according to FIG.

Referring to FIGS. 11A and 11B together, in the second coil unit 130C according to another embodiment, an opening OP1_T having a semicircular planar shape is formed in each of the upper plate TP_A and the lower plate BP_A of the second bobbin. , OP1_B) is formed to expose at least a part of the overlapping portion. Due to having such openings OP1_T and OP1_B, as shown in FIG. 11B, even if the height h2 of the accommodating space (ie, the height of the side wall SW) is smaller than twice the diameter D of the conductive wire, the bobbin A space for the conductive lines to cross can be secured without deformation of . Thus, an increase in the thickness of the second bobbin can be prevented.

Meanwhile, the maximum length h1 of the openings OP1_T and OP1_B in the uniaxial direction is preferably greater than twice (2*D) the diameter of each conductive line, as shown in FIG. 10 . In addition, it is preferable that the positions of the openings OP1_T and OP1_B include at least a portion of each of the four regions A1, A2, A3, and A4 in FIG. 10 where the conductive lines overlap each other. In addition, the planar area of the openings OP1_T and OP1_B is preferably 50% to 90% of the sum of the areas of the four regions A1, A2, A3, and A4 where overlapping between conductive lines occurs, but is not necessarily limited thereto.

In addition, the planar shape of the openings OP1_T and OP1_B is shown as a semicircle in FIG. 11A, but this is exemplary and may include at least a portion of each of the four regions A1, A2, A3, and A4 where overlapping between conductive lines occurs. If there is, it is not limited to its shape, such as circular, track-shaped, polygonal, etc. For example, as shown in FIG. 11C , the openings OP2_T and OP2_B of the second coil unit 130D may have a triangular planar shape.

The transformer according to the embodiments described so far has been described on the assumption that the second coil units 130, 130A, 130B, 130C, and 130D correspond to the secondary side coils of the transformer, but the second coil units 130, 130A, 130B, The configuration for reducing the inductance deviation applied to 130C and 130D) may be applied to the first coil unit 120 or both the first and second coil units.

In addition, as described above, the transformer 100 according to the embodiment may form a circuit board (not shown) constituting a power supply unit (PSU) together with other magnetic elements (eg, inductors).

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

100: transformer 111, 112: core part
120: first coil
130, 130A, 130B, 130C, 130D: second coil

Claims (1)

a core portion including an upper core and a lower core; and a bobbin at least partially disposed between the upper core and the lower core. and
A first coil part and a second coil part, at least partially disposed on the bobbin,
The bobbin,
A through hole formed in the central portion;
a first part disposed on one side of the bobbin in a first direction from the through hole;
A second part disposed on the other side facing the first part from the through hole; includes,
At least one of the first coil part and the second coil part,
Including a plurality of conductive lines disposed around the through hole,
One side of the plurality of conductive lines extends to be disposed on the second portion,
The other sides of the plurality of conductive wires extend so that both ends are disposed on the first portion,
A first conductive line and a second conductive line among the plurality of conductive lines include an overlapping portion in which at least a part overlaps on the second portion.

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