JPH08181018A - Coil device - Google Patents

Abstract

PURPOSE: To provide a coil device which has an improved energy efficiency of circuit operation and suppresses the noise source of electronic parts arranged at the periphery. CONSTITUTION: Coil patterns 8a and 8c are formed on the surface of a substrate 7 and coil patterns 8b and 8d are formed on the reverse side of the substrate 7. Adjacent coil patterns in vertical and horizontal directions are mutually wound inversely. The adjacent coil patterns are connected in series or parallel. The substrate 7 where the coil patterns 8a-8d are formed is laminated, thus forming an inductor or the coil device of a transformer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil device such as a transformer or an inductor.

[0002]

As is well known, coil devices such as transformers and inductors are used for switching power supplies and the like.
In recent years, in order to reduce the size and weight of switching power supplies, high-frequency circuit driving with a high switching frequency has been performed.

In general, an inductor used for a switching power supply is formed by winding a coil winding, and by inserting a core at the center of the coil winding, it is used as an inductor with a core. The one without is used as an air-core inductor. Also,
The transformer has a secondary coil formed by winding the coil winding in the vicinity of the primary coil formed by winding the coil winding, and the core is inserted at the center of the coil. Configured as a transformer.

An air-core transformer that does not use a core for the transformer is also proposed in, for example, Japanese Patent Application Laid-Open No. 61-102009, and this air-core transformer, as shown in FIG. It is formed by winding conductive foil films 2 and 3 with 1 sandwiched therebetween. By applying this, for example, as shown in FIG. 9, an insulator core 1 and one conductive foil film 2 are superposedly wound to form an air-core inductor using the conductive foil film as a coil. .

[0005]

When the switching power supply is made smaller and lighter and a high frequency circuit is driven,
The problem of adverse effects such as eddy current loss due to leakage magnetic flux from the coil cannot be ignored. FIG. 6 schematically shows a situation in which an eddy current is generated due to a leakage magnetic flux between coil windings. Windings 4a, 4b are wound next to each other,
4a, when the current I is flowing as shown, the winding 4a
In passing through the winding 4b of the leakage magnetic flux B is next generated, clockwise eddy current I _B is generated with respect to leakage flux in the conductor winding 4b by the leakage magnetic flux B, the eddy current loss is caused.

Further, the direction of the current I flowing through the winding 4b,
The direction of the eddy current I _B is an eddy current I _B becomes adding state to the current I becomes the same direction at the inner end of the winding 4b, winding 4b of the current I and the eddy current I _B Togagyaku the outer end As a result, the current I is attenuated and the current density flowing in the winding 4b becomes larger on the inner end side and smaller on the outer end side, resulting in an imbalance.
Since it passes through the surface region of b, the skin effect and the proximity effect that causes the imbalance of the current density act synergistically,
AC resistance increases. This eddy current loss and the phenomenon of increasing the AC resistance due to the skin effect and the proximity effect are caused by a leakage magnetic field generated from the winding 4b side passing through the adjacent winding 4a and winding 4a.
It is also generated by the eddy current generated on the side.

As described above, the phenomenon of eddy current loss and increase in AC resistance is caused between the windings of the inductors wound side by side, between the adjacent windings in the primary coil of the transformer, and also in the secondary coil of the transformer. Between adjacent windings of. Similarly, as shown in FIG. 7, the leakage magnetic flux B generated from the primary coil 5 of the transformer is transmitted through the secondary coil 6 to generate an eddy current I _{B in the} secondary coil 6, and similarly the secondary coil 6 is generated. An eddy current is generated in the primary coil 5 by the leakage magnetic flux emitted from the primary coil 5 passing through the primary coil 5, so that it is also generated between the primary coil 5 and the secondary coil 6 of the transformer. There is a problem that the increase in AC resistance due to the proximity effect and the skin effect and the eddy current loss are combined to reduce the energy efficiency of the circuit driving of the inductor and the transformer.

In particular, in the case of an open magnetic circuit type such as an air-core transformer or inductor, the leakage magnetic flux becomes strong, so that the influence is great, and in the case of a closed magnetic circuit type in which the core is inserted in the center of the coil. Also, in the case where a gap is provided between the abutting end faces of the core inserted in the coil,
The magnetic flux leaking from the gap passes through the coil,
Similar problems occur due to the generation of eddy currents.

Further, in the conventional coil device, the inductor and the transformer are constituted by one large coil (a pair of coils in the case of the transformer) in the case of the inductor and the transformer. The leakage magnetic flux leaking from is extremely strong, and the directionality of the leakage magnetic flux is radiated in a state where it is aligned even at a position far away from the inductor or transformer. The magnetic flux affects these electronic components to generate noise, which causes a problem that the electronic components malfunction. For this reason, electronic components cannot be mounted around inductors and transformers, and electronic components must be mounted at a sufficient distance from the inductors and transformers, resulting in extremely low packaging density. Has become a factor that prevents the miniaturization of.

The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to suppress the influence of eddy current due to leakage magnetic flux to improve the energy efficiency of circuit driving, and further, to reduce the inductor and transformer. To provide a coil device that weakens the energy of the generated leakage magnetic flux, loses the directionality of the leakage magnetic flux at a short distance from the inductor or transformer, and can mount electronic components around the inductor or transformer without any trouble. It is in.

[0011]

In order to achieve the above object, the present invention is constructed as follows. That is, in the coil device of the first invention, the coil patterns of a plurality of spiral conductors are formed adjacent to each other, the adjacent coil patterns are formed in reverse winding patterns, and the adjacent reverse winding coil patterns are connected in series. Alternatively, it is configured to be connected in parallel.

In the coil device according to the second aspect of the invention, in the configuration of the first aspect of the invention, the coil pattern is formed with slits extending along the direction in which the current flows so as to be stepped in the width direction of the coil pattern. It is characterized by being present.

Further, according to the third coil device of the present invention, a plurality of coils formed by winding a conductor are arranged adjacent to each other, adjacent coils are formed in reverse winding, and the adjacent coils of reverse winding are arranged. Are configured to be connected in series or in parallel.

[0014]

In the present invention having the above structure, a plurality of coil patterns (or coils) are arranged adjacent to each other, and the adjacent coil patterns (coils) are wound in reverse to each other. The currents flowing in the coil pattern (coil) and the coil pattern (coil) on the other side are in the same direction, and the adjacent coil patterns (coils) mutually strengthen each other to obtain a large inductance.

Further, since the coil device of the inductor or the transformer is formed by being dispersed into a plurality of coil patterns (coils), the energy of the leakage magnetic flux generated from each coil pattern (coil) portion is dispersed and becomes small. Therefore, the eddy current generated by the leakage flux passing through the coil pattern (coil) is also small, the eddy current loss is reduced, and the AC resistance due to the effect of the proximity effect and the skin effect is also reduced, The energy efficiency of coil drive is improved.

Moreover, as described above, since a plurality of coil patterns (coils) are arranged adjacent to each other, the energy of the leakage magnetic flux generated from each coil is dispersed and weakened. Moreover, since the adjacent coil patterns (coils) are wound in reverse, the leakage flux of each coil pattern (coil) that emerges from the outside of the assembly of coil patterns (coils) is aligned in opposite directions. Since there is no leakage flux,
At a short distance from the coil device, they interfere with each other and lose directionality. As a result, it does not act as a noise source on the electronic parts arranged in the peripheral part of the coil device, and it becomes possible to mount the electronic parts in the vicinity of the coil device. Miniaturization is achieved.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a main part configuration of a first embodiment of a coil device according to the present invention. In the figure, coil patterns 8a to 8d are formed on the front surface and the back surface of a flat plate-shaped substrate 7 made of an appropriate material such as ceramic, glass epoxy, and a flexible film by printing or vapor deposition. The coil patterns 8a and 8c shown in black in the figure are formed on the front surface side of the substrate 7, and the coil patterns 8b and 8d shown in white are formed on the back surface of the substrate 7. These coil patterns 8a to 8d are formed in a substantially square shape in this embodiment, and are adjacent coil patterns, that is, the coil patterns 8a adjacent to each other in the vertical direction of the drawing.
And 8b have a spiral coil pattern in which they are wound in opposite directions to each other.
And 8d also have a spiral pattern in which the windings are opposite to each other. Further, the coil patterns 8a and 8 that are adjacent to each other in the lateral direction are provided.
d also has a reverse winding pattern, and similarly, the coil patterns 8b and 8c adjacent to each other laterally also have a reverse winding spiral pattern.

A substrate 7 having these coil patterns 8a to 8d formed thereon is laminated with the centers of the coil patterns 8a to 8d aligned, and the coil patterns of the respective layers are connected to form an air-core inductor. Similarly, by stacking a plurality of substrates 7 on which the coil patterns 8a to 8d are formed, the coil pattern of one of the substrates is a primary coil, and the coil pattern of the other substrate is a secondary coil. Thus, an air-core transformer is formed, and further, by inserting the core into the central portion of each of the laminated coil patterns, an inductor and a transformer with a core are formed.

In the first embodiment, the coil patterns 8a-8d are connected in series with each other.

FIG. 2 shows the essential structure of a second embodiment of the coil device according to the present invention. In the second embodiment, the coil patterns 8a and 8d are formed on the front surface side of the substrate 7, the coil patterns 8b and 8c are formed on the rear surface side of the substrate 7, and the coil patterns 8a and 8b that are vertically adjacent to each other are connected in series. And the coil pattern 8c adjacent to each other in the vertical direction.
And 8d are also connected in series, and the series connection body of the coil patterns 8a and 8b and the series connection body of the coil patterns 8c and 8d are connected in parallel. Also in this second embodiment, vertically and horizontally adjacent coil patterns 8a to 8d are formed in spiral patterns in which windings are opposite to each other, and the substrate 7 on which these coil patterns 8a to 8d are formed is placed at the center of each coil pattern. By stacking together, an air-core inductor or transformer is formed, and an inductor or transformer with a core is formed by inserting the core in the center of the coil patterns 8a to 8d.

FIG. 3 shows the essential structure of a third embodiment of the present invention. In this embodiment, rectangular spiral coil patterns 9a and 9b are formed on the surface of a substrate 7 by printing or the like. The adjacent coil patterns 9a and 9b are connected in parallel. The coil patterns 9a and 9b are also adjacent to each other in a reverse winding pattern. By stacking the substrates 7 on which the coil patterns 9a and 9b are formed so that the center of each coil pattern 9a and 9b is aligned, Inductors and transformers are formed, and the cores are inserted through the central portions of the coil patterns 9a and 9b, whereby the inductors and transformers with cores are formed.

In the coil patterns 8a to 8d, 9a and 9b of the first to third embodiments, the coil patterns adjacent to each other are spiral patterns of reverse winding, so that the current flowing in the adjacent coil patterns. Are always in the same direction as indicated by the arrow. Therefore, the effect that the inductances of the adjacent coil patterns are mutually strengthened to obtain a large inductance is obtained. As described above, the large inductance can reduce the number of spirals in the spiral pattern when forming the coil having the inductance required in the circuit design, thereby reducing the electric resistance of the coil pattern. The excellent effect of being small can be obtained.

Further, in each of the above-mentioned embodiments, since the inductor and the transformer are constituted by a plurality of coil patterns,
As shown in FIG. 5A, a plurality of large coils (a transformer is a pair of coils) are used to form an inductor or a transformer as shown in FIG. The energy of the inductor and the transformer will be dispersed in the coil pattern portion of. Therefore, the energy of the leakage magnetic flux leaking from each coil pattern portion also becomes small. Therefore, when viewed as the entire inductor or the transformer as a whole, the concentration effect of the leakage magnetic flux concentrated at the center of the coil pattern is alleviated, and the leakage magnetic flux is reduced. This reduces the eddy current generated in the coil pattern, and
As a result of the effect of the proximity effect also becoming smaller, the imbalance of the current distribution flowing in the conductors of each coil pattern becomes smaller, and the increase in AC resistance due to the synergistic effect of the proximity effect and the skin effect is suppressed, and the eddy current due to the decrease in the eddy current is suppressed. Together with the effect of reducing the current loss, it becomes possible to sufficiently enhance the energy efficiency of the circuit drive of the inductor and the transformer.

Further, as shown in FIG. 5B, since the adjacent coil patterns are wound in opposite directions to each other, the leakage magnetic fluxes of the respective coil patterns, which are emitted from the outside of the assembly of coil patterns, have directions opposite to each other. Moreover, as described above, since the entire energy is dispersed by the plurality of coil patterns, the intensity of the leakage magnetic flux emitted from each coil pattern is also small. Therefore, at a position slightly distant from the inductor or the coil device of the transformer, the coil pattern The leakage magnetic fluxes from the outer periphery of the assembly interfere with each other and lose their directivity.As a result, the influence of the leakage magnetic flux becomes negligible at a position slightly apart from the position where the coil device is arranged. Since it does not affect the electronic parts as a power source, mount the electronic parts around the coil device. Possible and will, by this, the electronic component mounting density can be enhanced, and it is possible to significantly reduce the size of the apparatus in a switching power supply or the like having a coil apparatus of each embodiment.

FIG. 4 shows a fourth embodiment of the present invention. In the fourth embodiment, continuous slits extending in the direction of current flow, that is, the lengthwise direction of the coil pattern are formed in the coil patterns 8a to 8d, 9a and 9b of the first to third embodiments. 10 or more (2 in this figure)
This is the same as each of the above-described embodiments.

In the fourth embodiment, by providing the slit 10, the conductor of the coil pattern is divided into a plurality of suitable conductor portions 11a, 11b, 11c which are carved in the width direction. Therefore, when the leakage flux has passed through the coil pattern, for example, due to the eddy current I _B as shown in FIG. 7 even about to occur, the path of the eddy current is divided by the slit 10, the coil pattern conductor The generation of a large eddy current through almost the entire width of the coil pattern conductor is eliminated, the slit 10 engraves the coil pattern conductor in the width direction and divides it into a plurality of conductor portions 11a, 11b, 11c. Inside, a small eddy current with a small loop is generated.

By the way, when viewed on one coil pattern, the leakage magnetic flux concentrates on the central part of the coil pattern, and as a result, among the plurality of conductor parts 11a to 11c, the inner conductor part.
The eddy current generated in 11a becomes larger than the eddy current generated in the outer conductor portion 11c, but when the current flows in the adjacent coil pattern, the inner conductor portion 11a becomes the outer side in the adjacent coil pattern, and the outer conductor When the portion 11c moves to the adjacent coil pattern, it becomes an inner conductor portion, so that the current continuously flows through the plurality of coil patterns,
The eddy currents generated in the conductor portions 11a to 11c are also made almost uniform, and the current distribution is made uniform in each conductor portion.
This makes it possible to more effectively suppress an increase in AC resistance due to the proximity effect and the skin effect. In addition, by additionally providing the slit, the surface area of the coil pattern is increased, and thereby, the effect of reducing the conduction loss of the current due to the skin effect can be obtained.

In addition, looking at one coil pattern,
The length of the inner conductor portion 11a is the outermost conductor portion 11c.
Although the coil length is shorter than that, when the next adjacent coil pattern is formed, the innermost conductor portion 11a becomes the outermost one on the adjacent coil pattern and the outermost conductor portion 11c on the adjacent coil pattern. As a result of being the innermost one, when looking at a plurality of coil patterns comprehensively, each conductor part 11a, 11
The lengths of the conductors b and 11c are made uniform, so that the direct current resistance components of the conductor parts are also made uniform. That is, each conductor part
The impedances of 11a to 11c are uniform in terms of direct current and alternating current, and an excellent effect that the distribution of the current flowing through the conductor portions 11a to 11c can be made uniform can be achieved.

It is needless to say that the effect of each of the first to third embodiments can also be obtained in the fourth embodiment.

The present invention is not limited to the above-mentioned embodiments, and various embodiments can be adopted. For example, in each of the above embodiments, the coil patterns 8a to 8d, 9 are formed on the substrate 7.
By forming a and 9b and laminating the substrate 7 on which the coil pattern is formed, an inductor and a transformer are formed. Of course, the desired inductor is formed by a plurality of coil patterns formed on one substrate 7. When the number of turns of the conductor is sufficient, the inductor can be formed by the coil pattern of one substrate 7 without stacking the substrates 7.

Further, for example, the substrates 7 having the rectangular coil patterns 9a and 9b as shown in FIG. 3 are laminated, one of the substrates is used as a primary coil, and the coil pattern of the other substrate is used as a secondary coil. When the coil is used, for example, the coil patterns 9a and 9b used for the primary coil are connected in series and used as the secondary coil.
By connecting a and 9b in parallel, a transformer having a winding ratio of 2: 1 is formed, and it is determined whether adjacent coil patterns formed on the substrate 7 are connected in series or in parallel. The number of turns can be arbitrarily set according to the specifications.

Further, although the coil pattern is formed on the substrate in each of the above embodiments, the coil pattern may be formed by molding a conductive metal such as copper, and the substrate may be omitted.

Further, in the fourth embodiment, the slits are continuously provided along the lengthwise direction of the coil pattern over substantially the entire length of the coil pattern, but of course the slits may be provided discontinuously. However, in order to suppress the increase in AC resistance and reduce the eddy current loss due to the proximity effect and the skin effect, it is more desirable to provide the slit continuously.

Further, although the inside of the slit is a space in the embodiment, magnetic powder may be filled inside the slit (space portion). By doing so, the leakage magnetic flux escapes through the magnetic powder in the slit, so that the magnetic flux passing through the coil pattern is reduced, and the generation of eddy current can be almost eliminated.

Further, in each of the above-mentioned embodiments, the coil pattern type inductor and the transformer are described as an example, but of course, the coils wound with the coil winding (or the conductive foil film) are arranged side by side, and The adjacent coils may be reversely wound and the adjacent coils may be connected in series or in parallel to form an inductor or a transformer. Also in this case, the adjacent coils are reversely wound, and the energy is distributed to the plurality of coils, so that the energy efficiency and the mounting density can be improved, and the like as in the first to third embodiments. It becomes possible to exert an effect.

[0036]

According to the present invention, a coil device such as an inductor or a transformer is dispersed and formed in a plurality of spiral coil patterns (or a coil formed by winding a wire or a conductor such as a conductive foil film). As a result, the energy of the coil device is distributed to each coil pattern (coil) portion, and as a result, the intensity of the leakage magnetic flux generated in each coil pattern (coil) becomes smaller, which allows eddy currents to pass through the coil pattern (coil). By doing so, it is possible to suppress the generation of a large eddy current and suppress the increase in AC resistance due to the proximity effect and the skin effect due to this eddy current, and it is possible to remarkably improve the energy efficiency of coil driving.

Further, adjacent coil patterns (coils)
Since the coils are formed in reverse winding, the currents flowing through the conductors adjacent to each other in the coil patterns (coils) are always in the same direction, and the inductances of adjacent coil patterns (coils) strengthen each other, resulting in a large inductance value. The effect is obtained. Since a large inductance is obtained in this way, the number of turns of the conductor pattern (coil) required to obtain the inductance required in the circuit design may be small, and the electric resistance of the conductor pattern (coil) can be reduced accordingly. The benefit is that can be made smaller.

Further, as described above, by disposing a plurality of coil patterns (coils) adjacent to each other, energy is dispersed in each conductor pattern (coil) portion and a leakage magnetic flux is generated in each conductor pattern (coil) portion. In addition, the adjacent coil patterns (coils) are wound in opposite directions, so the leakage flux generated from the outside of the coil pattern (coil) assembly is opposite to each other in the adjacent coil patterns (coils). As a result, at a position slightly distant from the position where the coil device is arranged, the leakage magnetic fluxes emitted from these coil pattern coils interfere with each other and lose their directivity. Since it is possible to suppress the influence on the parts, it is possible to mount electronic parts around the coil device without any trouble. In the case where a switching power supply or the like is configured using the coil device of the present invention, electronic components can be mounted in the vicinity of the coil device, increasing the mounting density of electronic components and switching using the device of the present invention. It is possible to significantly reduce the size of devices such as a power supply.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a main part configuration of a coil device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a main part configuration of a second embodiment.

FIG. 3 is an explanatory diagram of a main part configuration of a third embodiment.

FIG. 4 is an explanatory diagram of a main part configuration of a fourth embodiment.

FIG. 5 is an explanatory view showing the energy dispersion effect of the present embodiment in a comparative state with the conventional example.

FIG. 6 is an explanatory diagram of a generation state of an eddy current generated in a winding on the other side by a leakage magnetic flux emitted from one side of adjacent windings.

FIG. 7 is an explanatory diagram of an eddy current generation state between a primary coil and a secondary coil of a transformer.

FIG. 8 is an explanatory diagram showing a configuration example of a conventional air-core transformer.

FIG. 9 is an explanatory diagram showing an example of a conventional air core inductor.

[Explanation of symbols]

 7 substrate 8a-8d, 9a, 9b coil pattern 10 slits 11a, 11b, 11c conductor portion

Claims (3)

[Claims] 1. A plurality of spiral conductor coil patterns are formed adjacent to each other, adjacent coil patterns are formed in reverse winding patterns, and the adjacent reverse winding coil patterns are connected in series or in parallel. A coil device characterized in that 2. The coil device according to claim 1, wherein the coil pattern is formed with slits extending along the direction of current flow, in a shape that is stepped in the width direction of the coil pattern. 3. A plurality of coils formed by winding a conductor are arranged adjacent to each other, adjacent coils are formed in reverse winding to each other, and the adjacent coils of the reverse winding are connected in series or in parallel. Coil device characterized by.