JPH07249528A - Planar magnetic parts - Google Patents

Abstract

PURPOSE:To provide such planar magnetic parts that the copper loss caused by the high coupling between a primary side and secondary side and a skin effect can be reduced and the parts can be inexpensively constituted and easily assembled keeping such features as high reliability and improved safety. CONSTITUTION:A coil is formed by printing spiral or U-shaped copper foil on the surfaces of multiple layers including one surface, both surfaces, or internal surface of a printed coil substrate 31 and clip leads 32 are fitted to the end faces of the substrate 31 in the width direction. Then the substrate 31 is put between an upper ferrite core 34 and lower ferrite core 35 and electrically connected to the circuit pattern of a mounting substrate 36 through the clip leads 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar type magnetic component, and more particularly to a planar type magnetic component used for a switching power source or the like and using a coil formed by printing a copper foil on a substrate.

[0002]

2. Description of the Related Art Planar type magnetic parts having a structure suitable for recent demands for higher frequency, smaller size and lower profile such as switching power supplies have been attracting attention. The planar type magnetic component is formed by printing a spiral or U-shaped conductor on a substrate instead of forming a coil by a wire such as an enameled wire as in the conventional case, and it is a high-order primary-secondary component. Bonding is feasible, increase in copper loss due to the skin effect can be suppressed to a minimum, and features such as improved quality reliability and stability are provided.

FIG. 6 is a diagram showing a conventional planar type magnetic component. For example, Japanese Utility Model Laid-Open Nos. 5-79914, 5-62008, 4-105512 and 4-11708. And JP-A-5-25
1250 and the like. In addition, FIG.
(A) shows an exploded perspective view, (b) shows a side sectional view.

In FIG. 6, a terminal block 1 has a plurality of terminals 2
And a plurality of sheet coils 3 each having a coil pattern 5 made of a conductor foil formed on at least one of the front and back of the insulating sheet 4 are laminated on the terminal block 1. At the end of each sheet coil 3, a terminal groove 3C having an opening on the end face is formed, and from the conductor foil, the terminal groove is electrically connected to the coil pattern 5 and the terminal groove not connected to the terminal groove is formed from a conductive foil. The land portion 6 is formed. The plurality of sheet coils 3 are stacked on the terminal block 1 and the terminal groove 3C is fitted to the terminal 2, and the land portion 6 and the terminal 2 are
And are soldered. Terminal block 1 core mounting holes 1A, 3A
The E core 8 is inserted into the E core 8 from below, and the I core 9 is attached to the E core 8 from above.

FIG. 7 is a diagram showing another example of a conventional planar type magnetic component, which is described in, for example, Japanese Patent Application Laid-Open Nos. 61-74311 and 61-75510. In addition, FIG. 7A shows a cross-sectional view of the front main part,
(B) shows a cross-sectional view of a main part of the plane, and (c) shows a side view.

In FIG. 7, a laminated wiring board 11 is formed by laminating a plurality of sheet coils each having a conductor pattern 15 of a coil formed on a thin insulating sheet, and the conductor patterns of each sheet coil are connected to each other by a connecting conductor 12. Is
The multi-winding coil of the transformer is formed as a whole. A part of the connecting conductor 12 is extended in the longitudinal direction so that the pin terminal 13
To provide a means for connecting the printed wiring board (not shown) to the circuit and fixing the transformer. The cores 14 and 16 are manufactured so as to be divided into upper and lower two sides, and both sides are aligned so as to sandwich the laminated wiring body 1 to form a magnetic circuit of a transformer.

FIG. 8 shows still another example of a conventional planar type magnetic component, which is disclosed in Japanese Utility Model Laid-Open No. 4-103612, Japanese Patent Laid-Open No. 5-55048 and Japanese Utility Model Laid-Open No. 4-12026.
It is described in Japanese Patent No. 4 publication. In FIG. 8, a coil pattern 22 is spirally formed on a printed wiring board 21, and core mounting holes 23, 2 are formed at the center and both sides thereof.
4, 25 are formed. Then, the core mounting hole 23,
The printed wiring board 21 at the portion where the coil pattern is formed is sandwiched from the front and back sides by the two ferrite cores 26 and 27 which are shaped so as to penetrate through 24 and 25 and be joined to each other.

[0008]

In the planar type magnetic component shown in FIG. 6, a plurality of sheet coils 3 each having a coil pattern 5 made of a conductor foil are laminated on a terminal block 1, and a land portion 6 and a terminal are further laminated. Since it is necessary to solder 2 and 2, there are drawbacks that the number of parts is large, the number of assembling steps is complicated, and the man-hour cost is high, which is disadvantageous in cost as compared with the conventional winding type.

Since the planar magnetic component shown in FIG. 7 uses the multilayer laminated wiring board 11, the terminal block 1 can be eliminated and the number of assembling steps can be reduced as compared with the planar magnetic component shown in FIG. Although there is an advantage that it can be done, there is a disadvantage that it is difficult to stand the pin terminal 13 vertically on the laminated wiring board 11, automation is difficult, and manual work is required.

In the planar type magnetic component shown in FIG. 8, the coil pattern 22 is directly formed on the printed wiring board 21 without using a plurality of laminated plates, and therefore, compared with the examples shown in FIGS. 6 and 7. Therefore, there is an advantage that the material cost and the number of assembling steps can be reduced, and there is an advantage that the mounting height of the component can be reduced. However, the printed wiring board 21 is limited to a printed circuit board such as glass epoxy, and the thickness of the laminate and the copper foil needs to be the same as the number of layers of the mounting board and the thickness of the copper foil. It has the drawback of being significantly limited.

Therefore, the main object of the present invention is to
A planar structure that can reduce the number of operations due to the high degree of secondary-secondary coupling and the skin effect, and can be constructed at low cost and can be assembled while keeping the features such as the reliability of quality and the improvement of stability. Type magnetic parts.

Another object of the present invention is to provide a planar type magnetic component which can be easily mounted without providing a mounting board with a mounting hole or the like.

Still another object of the present invention is to provide a planar type magnetic component capable of achieving a low profile.

[0014]

The invention according to claim 1 is
A coil is formed by printing a spiral or U-shaped metal foil on one side, both sides or a multilayer surface including the inner layer surface of the substrate,
In a planar type magnetic component in which the coil is sandwiched between magnetic material cores, a lead terminal connected to the coil is provided on an end surface of a substrate, and the lead terminal connects to an external conductor.

According to a second aspect of the present invention, a plurality of the substrates according to the first aspect are laminated, and the respective substrates are connected by lead terminals or the lead terminals and an external conductor.

According to a third aspect of the present invention, projecting portions are formed at different positions at the end portions of the plurality of substrates of the second aspect, and lead terminals are provided on the respective projecting portions.

According to a fourth aspect of the present invention, a coil is formed by printing a spiral or U-shaped metal foil on one surface, both surfaces or a multi-layer surface including the inner layer surface of a substrate to sandwich the coil with a magnetic material core. In the type magnetic component, an end face electrode connected to the coil is provided on the end face of the substrate, and the end face electrode connects to the external conductor.

In the invention according to claim 5, the magnetic material core according to claim 4 is provided with an end face electrode electrically connected to the end face electrode of the substrate.

According to a sixth aspect of the present invention, the mounting board further includes a hole into which the magnetic material core is dropped and a circuit pattern is formed. When the magnetic material core is dropped into the hole of the mounting board, the mounting board is mounted on the lower surface of the board. The surface of the substrate is in close contact, and the end face electrode and the circuit pattern are electrically connected.

[0020]

In the planar type magnetic component according to the first aspect, by using an inexpensive lead terminal widely used in a hybrid IC or the like on the end surface of the substrate, insertion and soldering when mounting the lead terminal on the substrate are performed. Can be automated.

According to the second aspect of the present invention, a plurality of boards to which the lead terminals are attached are laminated and the boards are electrically connected by the lead terminals or the lead terminals and the external conductors, thereby increasing the number of assembling steps. Without increasing
The cost increase of the substrate due to the increase in the number of layers can be suppressed.

According to the third aspect of the present invention, the projecting portions are formed at different positions on the end portions of the plurality of substrates, and the lead terminals are provided on the projecting portions, so that the lead terminals are in contact with each other even when a plurality of substrates are stacked. There is no such thing.

According to a fourth aspect of the present invention, the electrodes are formed on the end surface of the substrate without providing lead terminals.
It is possible to eliminate the step of inserting the lead terminal or the step of soldering, and further reduce the cost.

In the invention according to claim 5, by forming an end face electrode on the magnetic material core and electrically connecting the end face electrode and the end face electrode of the substrate, a lead terminal is not used and a mounting substrate is mounted. It is possible to eliminate the need to form a hole for dropping the magnetic material core.

According to the sixth aspect of the present invention, by forming a hole for dropping the magnetic material core in the mounting substrate, the lower surface of the substrate and the surface of the mounting substrate are brought into close contact with each other to reduce the mounting height. In addition, the end face electrode and the circuit pattern can be electrically connected.

[0026]

1 is a diagram showing a first embodiment of the present invention, in particular, (a) is an exploded perspective view and (b) is a side view when mounted on a substrate.

In FIG. 1, the planar type magnetic component 30 includes a printed circuit board 31, and a metal pattern such as a spiral or U-shaped copper foil is printed on one surface, both surfaces of each layer or a multilayer surface including an inner layer surface. . Electrical connection between the layers is made by through holes 33 or clip leads 32 as lead terminals. The clip lead 32 is a strip-shaped metal piece, one end of which is connected to a circuit on the upper surface of the printed coil board 31, and the other end is extended downward to be connected to a circuit on the lower surface of the printed coil board 31, or a mounting board. The pattern 36 is electrically connected by a solder fillet 37.

Further, ferrite cores 34 and 35 for sandwiching the printed coil board 31 from the upper surface and the lower surface are provided, and the ferrite cores 34 and 35 are provided with convex portions at both ends and the center to form an E-shaped core. There is. A rectangular hole 39 is formed in the central portion of the printed coil board 31 so that the central convex portions of the ferrite cores 34 and 35 fit into each other. Then, the ferrite cores 34 and 3 are provided in the holes 39.
The convex portion at the center of 5 is fitted, and the concave portions at both ends contact each other.

Therefore, according to this embodiment, an inexpensive lead terminal widely used in a hybrid IC or the like can be used as the clip lead 32, and insertion and soldering at the time of attaching to the printed coil board 31 can be automated.

An EI core may be used instead of the ferrite cores 34, 35, and the ferrite core 3
The convex portions 4, 35 may be cylindrical. Furthermore, the clip lead 32 does not have to be formed for surface mounting.

2A and 2B are views showing a second embodiment of the present invention. In particular, FIG. 2A is an exploded perspective view and FIG. 2B is a side view.

The embodiment shown in FIG. 2 is constructed similarly to FIG. 1 except for the following points. That is, the printed circuit board 32 shown in FIG.
Instead of this, the end face electrode 38 is formed. A hole 39 for dropping the ferrite core 35 is formed at the center of the mounting board 36. Therefore, the planar type magnetic component 30
When a is mounted on the mounting board 36, the lower surface of the printed coil board 31 is in close contact with the upper surface of the mounting board 36, and
8 and the pattern on the mounting substrate 36, the solder fillet 37
Can be electrically connected with.

Therefore, according to this embodiment, it is not necessary to insert the lead terminal into the printed coil board 31,
Moreover, the mounting height can be reduced.

3A and 3B are views showing a third embodiment of the present invention. FIG. 3A is an exploded perspective view, FIG. 3B is a side view at the time of mounting, and FIG. The figure is shown.

In the embodiment shown in FIG. 3, three printed coil boards 31 shown in FIG. 1 are laminated. That is, the printed coil boards 31a, 31b, and 31c are respectively configured in the same manner as the printed coil board 31 shown in FIG. 1, but the printed coil board 31a is formed so that one end in the short-side direction is projected. The clip lead 32a is attached to the printed coil board 31b, and the printed coil board 31b is formed with a projecting portion at the center in the lateral direction. And the clip lead 32c is attached thereto. Therefore, when the printed coil boards 31a, 31b and 31c are respectively superposed, the clip leads 32a, 32b and 3 are formed.
The lower end of 2c extends downward without overlapping.

Further, the printed coil boards 31a, 31
A hole 39 is formed at the center of b and 31c. The clip leads 32a, 32b, 32c are shown in FIG.
As shown in (b), the printed coil boards 31a, 31
The respective lengths are selected so that the printed coil boards 31a, 31b, 31c do not tilt when the b and 31c are mounted on the mounting board 36 in an overlapping manner. Ferrite cores 34 and 35 are fitted from above and below the laminated printed coil boards 31 a, 31 b and 31 c and mounted on a mounting board 36. And the clip lead 3
2a, 32b and 32c are electrically connected to the external pattern 40 on the mounting substrate 36 by the solder fillet 37.

In the embodiment shown in FIG. 3, when it is desired to increase the number of layers of the coil, the printed coil boards 31a, 3a are provided.
It is only necessary to stack 1b and 31c, and the cost increase of the printed circuit board due to the increase in the number of layers can be suppressed without significantly increasing the number of assembling steps. The number of printed circuit boards to be laminated is not limited or limited. Also, an insulating sheet may be inserted between the printed coil substrates to enhance electrical insulation between the substrates.

4 and 5 are views showing a fourth embodiment of the present invention. In particular, FIG. 4 is an exploded perspective view, and FIG.
(A) is a side view when mounted, and (b) is a plan view when mounted.

The embodiment shown in FIGS. 4 and 5 is an improvement of the second embodiment, in which the printed coil board 31 is placed on the upper part of the I-shaped core 41, and E from the top.
The mold core 34 is fitted therein. End-face electrodes 42 are formed on the end face of the I-shaped core 41 in the lateral direction, and these end-face electrodes 42 are electrically connected to the end-face electrodes 38 of the printed coil board 31 by solder fillets 44. Then, the E-shaped core 34 is fitted into the hole 39 of the printed coil board 31. Further, a circuit pattern (not shown) is formed on the upper surface of the mounting substrate 36, and the end face electrode 42 is formed on the circuit pattern by the solder fillet 4.
5 electrically connected.

As described above, in this embodiment, the end face electrode 42 is formed on the I-shaped core 41 and the printed coil board 31 is formed.
Since the end surface electrode 38 is directly connected to the end surface electrode 42, it is not necessary to form a hole for embedding the core in the mounting substrate 36, and the height can be reduced.

[0041]

As described above, according to the invention of claim 1, since the inexpensive lead terminal widely used in the hybrid IC etc. is used as the terminal, it is possible to insert the terminal into the printed coil board. Soldering can be automated, and material costs and assembly man-hours can be significantly reduced. As a result, it is possible to realize high efficiency, downsizing, and thinning when used in a power module such as a switching power supply without increasing the cost as compared with a winding type magnetic component.

According to the second aspect of the present invention, by laminating a plurality of the substrates according to the first aspect and connecting the respective substrates by the lead terminals or the lead terminals and the external terminals, the number of assembling steps is not significantly increased. Therefore, the cost increase of the printed circuit board due to the increase in the number of layers can be suppressed.

According to the third aspect of the invention, the projecting portions are formed at different positions on the end portions of the plurality of substrates, and the lead terminals are provided on the projecting portions. The terminals do not touch each other.

According to the fourth aspect of the present invention, since the end face electrode is formed on the end face of the substrate and the end face electrode is connected to the external conductor, it is not necessary to provide a lead terminal, and the material cost can be reduced. Not only that, the lead terminal insertion and the soldering process can be eliminated, so that the cost can be further reduced.

According to the fifth aspect of the present invention, the end face electrode is formed on the magnetic material core, and the end face electrode and the end face electrode of the printed coil board are electrically connected to each other, whereby the thickness can be reduced. .

According to the invention of claim 6, the mounting height of the component can be reduced by forming the hole for dropping the magnetic material core in the mounting substrate.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a second embodiment of the present invention.

FIG. 3 is a diagram showing a third embodiment of the present invention.

FIG. 4 is an exploded perspective view showing a fourth embodiment of the present invention.

FIG. 5 is a side view and a plan view of a fourth embodiment of the present invention.

FIG. 6 is a diagram showing a conventional planar type magnetic component.

FIG. 7 is a diagram showing another example of a conventional planar type magnetic component.

FIG. 8 is a diagram showing still another example of a conventional planar type magnetic component.

[Explanation of symbols]

31, 31a, 31b, 31c Printed coil board 32 Lead terminal 33 Through hole 34, 35 Ferrite core 36 Mounting board 37 Solder fillet 38 End face electrode of printed coil board 39 Core drop hole 40 Outer conductor 41 I-type magnetic material core 42 Magnetic Material core end face electrode 44 Print coil substrate end face electrode-magnetic material core end face electrode connecting solder fillet 45 Magnetic material core end face electrode-mounting substrate connecting solder fillet

Claims (6)

[Claims] 1. A planar magnetic component in which a spiral or U-shaped metal foil is printed on one surface, both surfaces or a multilayer surface including an inner layer surface of a substrate to form a coil, and the coil is sandwiched by a magnetic material core. A planar type magnetic component characterized in that a lead terminal connected to the coil is provided on an end face of the substrate and is connected to an external conductor by the lead terminal. 2. The planar magnetic component according to claim 1, wherein a plurality of the substrates are laminated, and the substrates are connected by the lead terminal or the lead terminal and an external conductor. 3. The planar magnetic component according to claim 2, wherein protrusions are formed at different positions on the ends of the plurality of substrates, and the lead terminals are attached to the respective protrusions. 4. A planar type magnetic component comprising a coil formed by printing a spiral or U-shaped metal foil on one surface, both surfaces or a multilayer surface including an inner layer surface of a substrate, and sandwiching the coil with a magnetic material core, An end face electrode connected to the coil is provided on an end face of the substrate, and is connected to an external conductor by the end face electrode. 5. The planar magnetic component according to claim 4, wherein the magnetic material core is formed with an end face electrode electrically connected to the end face electrode of the substrate. 6. The planar type magnetic component according to claim 4, further comprising a hole into which the magnetic material core is dropped, and a mounting substrate on which a circuit pattern electrically connected to the end face electrode is formed.