Inductance component

Abstract

To avoid an adverse influence such as an increase of a surge voltage, improve performance of a power supply device, etc., and further improve stability and reliability by effectively reducing leakage inductance.SOLUTION: When configuring an inductance component 1 comprising one or two or more sheet coils C2 ... configured in one or two or more turns and a pair of connection terminals 3a and 3b provided in a pair of coil ends C2a ..., C2b ..., in each sheet coil C2 ... to be connected to an external circuit, a pair of opposite parts 4a and 4b, which can be opposed mutually, each including a predetermined area is connected between the connection terminals 3a and 3b corresponding to the coil ends C2a ... and C2b ... and a leakage magnetic flux cancellation function section 6 is provided in which the opposite arts 4a and 4b are oppositely coupled via an insulation sheet 5 having a predetermined thickness Lc.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an inductance component suitable for use in a planar transformer or the like using a sheet coil.

Background Art

[0002] Conventionally, as planar transformers configured using sheet coils (flat rectangular conductors), the "planar transformer" described in Patent Document 1 and the "planar coil component" described in Patent Document 2 are known.

[0003] The planar transformer of Patent Document 1 does not require a mold or the like for forming the coil, facilitates prototyping and coil turn changes in the design and development stage, shortens the development time, reduces the development cost, lowers the product unit price, and aims to reduce the capacitance distributed between coils. Specifically, a plurality of unit wire coils are formed by winding a wire in a spiral shape a plurality of times and overlapping adjacent wires so that they contact each other, and then connecting a plurality of the unit wire coils to form a wire coil in a flat plate ring shape. It also includes a conductive plate coil formed by connecting a plurality of unit conductive plate coils with the conductive plate in a flat plate ring shape, and has a configuration in which the surfaces of the unit wire coil and the unit conductive plate coil face each other and are alternately stacked. In particular, the tip of the unit wire coil is extended as it is to form an external terminal.

[0004] Also, the planar coil component of Patent Document 2 aims to enhance the heat dissipation of the wiring layer and suppress the shape change of the insulating layer. Specifically, it includes a plurality of wiring layers and a plurality of ceramic layers alternately laminated with the plurality of wiring layers. For at least one of the plurality of ceramic layers, a first metallized layer is formed on the upper surface in the lamination direction where the plurality of wiring layers and the plurality of ceramic layers are laminated, and a second metallized layer is formed on the lower surface in the lamination direction, separated from the first metallized layer. At least one of the first metallized layer and the second metallized layer is joined to the opposing wiring layer. In particular, the protruding portion of the planar coil is configured as a connection terminal.

Prior Art Documents

Patent Document

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the conventional inductance components such as planar transformers and planar coil components had the following problems.

[0007] That is, with the practical application of next-generation compound semiconductor devices represented by SiC (silicon carbide) and GaN (gallium nitride), in power supply devices using planar transformers, the switching frequency tends to become higher, and accordingly, non-negligible adverse effects such as an increase in surge voltage due to leakage inductance occur. Therefore, more than ever, reducing leakage inductance has become important.

[0008] Conventionally, in inductance components such as planar transformers, when reducing leakage inductance, measures have been taken to increase the number of layers of the primary winding and the secondary winding and improve the magnetic coupling between the primary winding and the secondary winding. For example, in the planar transformer exemplified in the present embodiment described later, according to the simulation when one layer is added to the secondary winding and a general connection terminal is adopted, the leakage inductance of the transformer body part (the overlapping part of the primary winding and the secondary winding) can be almost halved. On the other hand, although the leakage inductance of the transformer body part can be greatly reduced, the leakage inductance on the connection terminal side is not reduced. Therefore, the effect of reducing the leakage inductance of the entire transformer cannot be sufficiently obtained, and an effective reduction measure for the leakage inductance on the connection terminal side has been demanded more than before.

[0009] The object of the present invention is to provide an inductance component that solves the problems existing in such background art.

Means for Solving the Problems

[0010] In order to solve the above-described problems, the present invention provides an inductance component 1 including at least one or more sheet coils C2... configured with one or two or more turns and a pair of connection terminals 3a, 3b provided at a pair of coil end portions C2a..., C2b... in each sheet coil C2... for connecting to an external circuit. When configuring the inductance component 1, a pair of facing portions 4a, 4b having a predetermined area capable of facing each other are respectively connected between each coil end portion C2a..., C2b... and the corresponding connection terminal 3a, 3b, and a leakage flux cancellation function portion 6 is provided in which the facing portions 4a and 4b are face-coupled via an insulating sheet 5 having a predetermined thickness Lc.

[0011] In this case, according to a preferred embodiment of the invention, it is desirable to apply the sheet coil C2... to a sheet coil for a planar transformer. Further, the facing portions 4a, 4b may be integrally formed with the coil end portions C2a..., C2b... or may be integrally formed with the connection terminals 3a, 3b. At this time, a coil coupling portion 6a, 6b having one or two or more coupled portions 6aj..., 6bj... respectively coupled to the coil end portions C2a..., C2b... in each sheet coil C2... can be integrally provided on the facing portions 4a, 4b. On the other hand, the insulating sheet 5 can be provided with adhesive surfaces 5j, 5j for the facing portions 4a, 4b on both sides.

Effects of the Invention

[0012] According to the inductance component 1 according to the present invention having such a configuration, the following remarkable effects can be obtained.

[0013] (1) The inductance component 1 connects a pair of opposing surfaces 4a and 4b, each having a predetermined area that can face each other, between the coil end portions C2a..., C2b... and the connection terminals 3a, 3b, respectively, and provides a leakage flux cancellation function portion 6 in which the opposing surfaces 4a and 4b are face-coupled via an insulating sheet 5 having a predetermined thickness Lc. Therefore, even when the switching frequency in a power supply device or the like increases, the leakage inductance can be effectively reduced by the leakage flux cancellation function of the leakage flux cancellation function portion 6. As a result, adverse effects such as an increase in surge voltage due to the leakage inductance can be avoided, and the performance of the power supply device or the like can be improved, and further, the stability and reliability can be enhanced.

[0014] (2) According to a preferred embodiment, if the sheet coil C2... is applied to a sheet coil for a planar transformer, it can be applied to a planar transformer in which the adverse effect of the leakage inductance is likely to be relatively large, so that it can be implemented as an optimal form from the viewpoint of ensuring an effective effect.

[0015] (3) According to a preferred embodiment, if the opposing surfaces 4a and 4b are integrally formed with the coil end portions C2a..., C2b..., the coil end portions C2a..., C2b... can be directly used, which contributes to cost reduction and miniaturization by reducing the number of parts, and can enhance the diversity in implementation.

[0016] (4) According to a preferred embodiment, if the opposing surfaces 4a and 4b are integrally formed with the connection terminals 3a, 3b, the connection terminals 3a, 3b and the opposing surfaces 4a, 4b can be used in common, which contributes to cost reduction and miniaturization by reducing the number of parts.

[0017] (5) According to a preferred embodiment, if a coil coupling portion 6a, 6b having one or more coupled portions 6aj..., 6bj... that are respectively coupled to the coil end portions C2a..., C2b... in each sheet coil C2... is integrally provided on the opposing surfaces 4a, 4b, the respective functional portions of each of the sheet coils C2..., the opposing surfaces 4a, 4b, and the coil coupling portion 6a, 6b can be rationally arranged. Therefore, the effect can be ensured, and it can be implemented as an optimal form from the viewpoint of achieving overall miniaturization.

[0018] (6) In a preferred embodiment, when configuring the insulating sheet 5, by providing adhesive surfaces 5j, 5j on both sides for the opposing portions 4a, 4b, the additional leakage magnetic flux cancellation functional portion 6 can be easily assembled, and commercially available double-sided tapes and the like can also be used, so that it can be implemented at low cost.

Brief Description of the Drawings

[0019]

Figure 1

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Figure 13

Embodiments for Carrying Out the Invention

[0020] Next, preferred embodiments according to the present invention will be given and described in detail with reference to the drawings.

[0021] First, the configuration of the inductance component 1 according to the present embodiment will be described mainly with reference to FIGS. 1 to 8.

[0022] Note that the embodiment exemplifies the case where it is applied to the planar transformer 10 as the inductance component 1. Thereby, since it can be applied to a planar transformer in which the adverse effect of leakage inductance tends to be relatively large, it can be implemented as an optimal form from the viewpoint of ensuring an effective effect.

[0023] FIG. 1 shows the external configuration of the planar transformer 10 used in a power supply device such as a DC-DC converter. The exemplified planar transformer 10 includes a 6-turn primary winding M1 and a 1-turn secondary winding M2, and a low voltage (exemplified as DC12 [V]) / large current is output from the connection terminals (output terminals) 3a and 3b of the secondary winding M2. In this case, the secondary winding M2 arranges the secondary-side sheet coils C2 shown in FIG. 3 in three layers as shown in FIG. 2, and the respective sheet coils C2, C2, and C2 are connected in parallel. On the other hand, the primary winding M1 arranges the sheet coil C1 shown in FIG. 4 in two layers as shown in FIG. 2, and the sheet coils C1 and C1 are connected in series.

[0024] First, the principle of reducing the leakage inductance in the planar transformer 10 according to the present embodiment will be described with reference to FIG. 1.

[0025] The virtual lines shown in FIG. 3 indicate the conventional general coil ends C2ar and C2br in the sheet coil C2. Note that 3ar and 3br indicate connection terminals. As is clear from the figure, the respective currents flowing through the pair of coil ends C2ar and C2br are in opposite directions, and the leakage magnetic fluxes generated from the coil ends C2ar and C2br cancel each other out. Therefore, from the viewpoint of canceling the generated leakage magnetic flux, the layout of the coil ends C2ar and C2br was optimized and verified.

[0026] That is, FIG. 1 shows the planar transformer 10 according to the present embodiment. A pair of opposing portions 4a and 4b having a predetermined area capable of facing each other are respectively connected between each coil end C2a..., C2b... and each connection terminal 3a, 3b, and a leakage flux cancellation functional portion 6 is provided in which the opposing portions 4a and 4b are face-to-face coupled via an insulating sheet 5 having a predetermined thickness Lc. As a result, the leakage inductance could be reduced without being greatly affected by the size of the predetermined area where the opposing portions 4a and 4b can face each other and the size of the predetermined thickness Lc.

[0027] FIG. 8 shows the measured values of the leakage inductance according to the present embodiment (this example) and the leakage inductance according to the conventional example. In this case, the configurations and shapes on the main body side of the sheet coils C2... in the conventional example and the present example are the same. As a result, the leakage inductance of the conventional example was 580 [nH] as described above, but the leakage inductance of the present example was approximately half, 270 [nH], confirming the effectiveness of the present invention.

[0028] Next, a method for manufacturing the planar transformer 10 according to the present embodiment will be described with reference to FIGS. 1-8 and FIGS. 10-13 according to the flowchart shown in FIG. 9.

[0029] First, punching materials for each component are obtained by punching a copper plate having a predetermined thickness (step S1).

[0030] The upper part of FIG. 6 shows an L-shaped opposing plate material 11p which is one of the punching materials. Two of these opposing plate materials 11p are prepared (step S2). One of the opposing plate materials 11p has a rectangular portion located in the middle as the opposing portion 4a, and one of the extending portions is bent at a right angle along a folding line K1 to form the connection terminal 3a, and the other is bent at a right angle along a folding line K2 to form the portion to be coupled 6a. In this case, as shown in FIG. 5, three coupling hole portions 6aj... for coupling the coil ends C2a... of the three sheet coils C2... constituting the secondary winding M2 described later are formed in the portion to be coupled 6a. As a result, one of the bent opposing members 12a shown in the lower part of FIG. 6 is obtained (step S3).

[0031] On the other hand, for the other facing plate member 11p, a rectangular portion located in the middle is used as the facing portion 4b. One of the extending portions is bent at a right angle to the opposite side with respect to the facing member 12a along the broken line K1 to form the connection terminal 3b, and the other is bent at a right angle to the opposite side with respect to the facing member 12a along the broken line K2 to form the portion to be coupled 6b. Similar to the above-described facing member 12a, three coupling hole portions 6bj... for coupling the other coil end portions C2b... in the three sheet coils C2... are formed in the portion to be coupled 6b. As a result, the bent other facing member 12b shown in the lower part of FIG. 6 is obtained (step S4).

[0032] In this way, if the facing portions 4a and 4b are integrally formed with the connection terminals 3a and 3b, the connection terminals 3a and 3b can also be used as the facing portions 4a and 4b, contributing to cost reduction and miniaturization by reducing the number of parts. Further, if the facing portions 4a and 4b are integrally provided with the portions to be coupled 6a and 6b having the coupling hole portions 6aj... and 6bj... for connecting to the coil end portions C2a... and C2b... in the respective sheet coils C2..., the respective functional portions of the respective sheet coils C2..., the facing portions 4a and 4b, and the coil coupling portions 6a and 6b can be rationally arranged, ensuring the effects and implementing in an optimal form from the viewpoint of overall miniaturization.

[0033] In the embodiment, an example in which the opposing surfaces 4a and 4b are integrally formed with the connection terminals 3a and 3b has been shown. However, as another configuration, the opposing surfaces 4a and 4b may be integrally formed with the coil end portions C2a and C2b. That is, since the sheet coil C2 and the opposing surfaces 4a and 4b can be punched out from the same copper plate, the integration of the opposing surfaces 4a and 4b and the coil end portions C2a and C2b is also easy by the shape of the coil end portions C2a and C2b and some bending processes. In this case, the coil end portions C2a and C2b forming the opposing surfaces 4a and 4b are formed on the coil end portions C2a and C2b of a selected single sheet coil C2, and the coil end portions C2a... and C2b... of other sheet coils C2... may be connected in parallel by overlapping and joining the whole. Also in this case, since the coil end portions C2a... and C2b... can be directly used, it can contribute to cost reduction and miniaturization by reducing the number of parts. Furthermore, it is also possible to integrally configure the three members of the coil end portion C2a... (the same applies to the coil end portion C2b... side), the opposing surface 4a, and the connection terminal 3a by continuously forming them.

[0034] And when a pair of opposing surface members 12a and 12b are obtained, as shown in the lower part of FIG. 6, the opposing surfaces 4a and 4b are opposed and joined via an insulating sheet 5 having a predetermined thickness Lc. Thereby, the leakage magnetic flux canceling function portion 6 is configured (step S5). When configuring the insulating sheet 5, adhesive surfaces 5j and 5j for the opposing surfaces 4a and 4b are provided on both surfaces. With such a configuration, the leakage magnetic flux canceling function portion 6 can be easily assembled. In particular, the voltage of the secondary winding M2 on the output side becomes a low voltage of about 12 [V], and when selecting the thickness Lc, since the withstand voltage is not required so much, a commercially available double-sided tape or the like can also be used, and it can be implemented at low cost. As another means, a resin plate formed to a predetermined thickness Lc may be prepared and pasted by applying a necessary adhesive or the like, and it can be easily replaced by various means having the same insulating function.

[0035] On the other hand, the punched material obtained by the above-described punching process includes the primary side sheet coil C1 shown in FIG. 4 used for the primary winding M1 and the secondary side sheet coil C2 shown in FIG. 3 used for the secondary winding M2.

[0036] The primary-side sheet coil C1 is formed in a rectangular spiral shape with a total of 3 turns. In this case, two sheet coils C1 are prepared. One sheet coil C1 is used in the upper stage, and the other sheet coil C1 is used in the lower stage.

[0037] As shown by the solid line in FIG. 4, for one sheet coil C1, the outer end portion located on the outer side is formed at one input terminal (connection terminal) C1a of the primary winding M1, and the inner end portion located on the inner side is formed at the intermediate connection portion C1am. At this time, as shown in FIG. 13, the intermediate connection portion C1am is bent and formed in a crank shape downward. Also, the other sheet coil C1 is used with the top and bottom reversed. Thereby, as shown by the virtual line in FIG. 4, the outer end portion located on the outer side is formed at the other input terminal (connection terminal) C1b of the primary winding M1, and the inner end portion located on the inner side is formed at the intermediate connection portion C1bm. At this time, as shown in FIG. 13, the intermediate connection portion C1bm is bent and formed in a crank shape upward (step S6).

[0038] As shown in FIG. 3, the secondary-side sheet coil C2 is formed in a rectangular shape with a total of 1 turn, and a pair of coil end portions C2a, C2b adjacent to one of the pair of short side portions are formed. In this case, coupling convex portions C2aj, C2bj are respectively formed at the tips of the coil end portions C2a, C2b. These coupling convex portions C2aj, C2bj are respectively inserted into the aforementioned coupling hole portions 6aj, coupling hole portions 6bj. Three sheet coils C2 are prepared (step S7).

[0039] Thus, in order to obtain the required main components, namely, the primary-side sheet coil C1…, the secondary-side sheet coil C2…, and the leakage flux canceling function portion 6, the assembling process of the planar transformer 10 is performed.

[0040] First, as shown in FIG. 10, at the lowermost position, the secondary-side sheet coil C2 is set, and a rectangular frame-shaped insulating plate 21 integrally formed with an insulating resin or the like having a predetermined thickness is placed on the upper surface of this sheet coil C2. Further, the primary-side sheet coil C1 used on the lower stage is placed on the upper surface of this insulating plate 21 (step S8). Next, the insulating plate 21 is placed on the upper surface of this primary-side sheet coil C1, and the secondary-side sheet coil C2 is placed on the upper surface of this insulating plate 21 (step S9). These stacking steps are sequentially and alternately performed until the primary-side sheet coil C1... and the secondary-side sheet coil C2... disappear. Thereby, a laminate U1 shown in FIG. 11 is obtained (steps S10, S8...).

[0041] In this laminate U1, in the exemplary case, from the lowermost secondary-side sheet coil C2 to the uppermost secondary-side sheet coil C2, it is stacked in the order of "secondary-side sheet coil C2" + "insulating plate 21" + "primary-side sheet coil C1" + "insulating plate 21" + "secondary-side sheet coil C2" + "insulating plate 21" + "primary-side sheet coil C1" + "insulating plate 21" + "secondary-side sheet coil C2". In such stacking, it is desirable to consider preventing displacement, such as by temporary fixing or positioning.

[0042] When the stacking process is completed, as shown in FIG. 13, the lower surface of the intermediate connection portion C1am of the sheet coil C1 located on the upper stage side in the laminate U1 and the upper surface of the intermediate connection portion C1bm of the primary-side sheet coil C1 located on the lower stage side are joined by welding or soldering (step S11). Next, the laminate U1 is set in a molding machine, and insert molding is performed to cover the periphery of the laminate U1 with an insulating resin 22 (step S12). FIGS. 12 and 13 show an intermediate assembly U2 in which the periphery of the laminate U1 is covered with the insulating resin 22. The intermediate assembly U2 covers the periphery of the laminate U1 excluding the pair of coil end portions C2a and C2b and the pair of input terminals (connection terminals) C1a and C1b with the insulating resin 22, and an insertion hole portion U2s for inserting a core is provided in the middle to form the whole in a rectangular frame shape.

[0043] Next, as shown in FIG. 12, coupling convex portions C2aj..., C2bj... formed at each coil end C2a..., C2b... in the secondary-side sheet coil C2... are inserted into respective coupling hole portions 6aj..., 6bj... of the coupled portions 6a..., 6b... in the leakage flux canceling function portion 6, and fixed by welding or soldering or the like (step S13). Further, as shown in FIG. 13, a pair of core halves 23u, 23d are attached to the intermediate assembly U2 from above and below (step S14). After that, as shown in FIG. 1, taping 24 is applied to the outer peripheral surfaces of the attached core halves 23u, 23d, and if finishing processing is performed as necessary, the target planar transformer 10 shown in FIGS. 1 and 7 can be obtained (step S15).

[0044] Therefore, according to such a planar transformer 10 (inductor component 1) according to this embodiment, as a basic configuration, a pair of facing portions 4a, 4b having a predetermined area capable of facing each other are respectively connected between each coil end C2a..., C2b... and the corresponding connection terminals 3a, 3b, and between the facing portions 4a and 4b, a leakage flux canceling function portion 6 is provided which is face-coupled via an insulating sheet 5 having a predetermined thickness Lc. Thus, for example, even when the switching frequency in a power supply device or the like becomes high, the leakage inductance can be effectively reduced by the leakage flux canceling function of the leakage flux canceling function portion 6. Thereby, adverse effects such as an increase in surge voltage due to the leakage inductance can be avoided, and the performance of the power supply device or the like can be improved, and furthermore, the stability and reliability can be enhanced.

[0045] Although the preferred embodiments have been described in detail above, the present invention is not limited to such embodiments, and can be arbitrarily changed, added, or deleted in terms of the detailed configuration, shape, material, quantity, numerical value, etc., without departing from the gist of the present invention.

[0046] For example, the one-turn sheet coil C2 on the secondary side and the six-turn sheet coil C1 on the primary side were exemplified, but the number of turns of these is arbitrary. Also, although the leakage flux canceling function unit 6 was shown as being provided in the sheet coil C2, it may be provided in the sheet coil C1 if necessary. Further, although the sheet coils C2..., C1... were manufactured by punching a copper plate, they may be formed by directly etching the sheet material provided on the upper surface of the insulating plate 21. Note that the copper plate is an example, and various conductive materials can be used. The opposing portions 4a, 4b of the leakage flux canceling function unit 6 were shown as being integrally formed with the coil end portions C2a..., C2b... and also integrally formed with the connection terminals 3a, 3b. However, a leakage flux canceling function unit 6 constituted only by the opposing portions 4a, 4b and the insulating sheet 5 may be configured, and the coil end portions C2a..., C2b... may be connected to this leakage flux canceling function unit 6, or separate connection terminals 3a, 3b may be connected. Furthermore, the insulating sheet is, so to speak, a means for preventing contact. Therefore, any sheet-like material that can prevent contact is sufficient, for example, an air layer (air sheet) or the like may be used.

Industrial Applicability

[0047] The inductance component according to the present invention can be used for various inductance components such as planar transformers and choke coils using sheet coils.

Explanation of Signs

[0048] 1: Inductance component, 3a: Connection terminal, 3b: Connection terminal, 4a: Opposing portion, 4b: Opposing portion, 5: Insulating sheet, 5j: Adhesive surface, 6: Leakage flux canceling function unit, 6a: Coil coupling portion, 6b: Coil coupling portion, 6aj...: Portion to be coupled, 6bj...: Portion to be coupled, C2...: Sheet coil (secondary side sheet coil), C2a...: Coil end portion, C2b...: Coil end portion, Lc: Predetermined thickness

Claims

1. An inductance component comprising at least one or more sheet coils formed in one or two or more turns, and a pair of connection terminals provided at a pair of coil ends in each sheet coil for connection to an external circuit, wherein a pair of opposing surfaces having a predetermined area capable of facing each other are respectively connected between each coil end and the corresponding connection terminal, and a leakage magnetic flux canceling function part in which the opposing surfaces are face-coupled via an insulating sheet having a predetermined thickness is provided.

2. The inductance component according to claim 1, wherein the sheet coil is applied to a sheet coil for a planar transformer.

3. The inductance component according to claim 1, wherein the opposing surface is integrally formed at the coil end.

4. The inductance component according to claim 1, wherein the opposing surface is integrally formed at the connection terminal.

5. The inductance component according to claim 4, wherein the opposing surface integrally includes a coil coupling part having one or more parts to be coupled respectively coupled to the coil ends in each sheet coil.

6. The inductance component according to claim 1, wherein the insulating sheet has an adhesive surface for the opposing surface on both sides.

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