JP2002280230A - Planar coil and planar transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a planar coil, capable of reducing in thickness and having a winding of odd turns and high flexibility in designing the number of conductor layers and a small loss and a planar transformer. SOLUTION: The planar coil comprises an insulation layer 10, a first conductor layer 11, having a first conductor pattern 11a formed by disposing a flat plate-like conductor in a spiral state, and a second conductor pattern, formed by disposing a flat plate-like conductor in a spiral state. The coil further comprises a second conductor layer, superposed on the first conductor layer via the insulation layer 10. A first pattern 11a and a second pattern each has a winding part of N (N is an integer of 1 or larger)+1 turns. In the pattern 11a and the second pattern, the width of the winding part at the innermost side is a substantially half the width of another winding part. The innermost winding parts are connected in parallel, and the winding of (2N+1) turns is constituted of the first pattern 11a and the second pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar coil and a planar transformer having a winding composed of a conductor pattern formed by spirally arranging flat conductors.

[0002]

2. Description of the Related Art A planar coil or a transformer is used as a choke coil or a transformer in a switching power supply or the like. A planar coil or a planar transformer has a winding composed of a conductor pattern formed by spirally arranging flat conductors. In a planar coil having a planar transformer and a plurality of conductor patterns, a plurality of conductor patterns are stacked in the thickness direction via an insulating layer.

[0003] Of the planar coils and transformers, those having a relatively small output current are formed by stacking spiral conductive patterns, insulating layers and magnetic layers by a thin film forming technique such as sputtering. Among the plane coils and plane transformers, those having a medium output current can be formed, for example, by etching a conductor layer on each surface to form a spiral conductor pattern on each surface, and interposing an insulating layer on the double-sided printed circuit board. Printed coils that are formed by laminating them, and coils that are formed by laminating spiral conductive patterns formed by punching a conductive plate via an insulating layer are used. In these coils, a hole penetrating in the thickness direction is formed at the center of the spiral conductor pattern, and a magnetic material such as an EE type ferrite core is inserted into this hole.

[0004] The above-mentioned planar coils and planar transformers can be made thinner, and thus are used particularly for small and thin switching power supplies.

[0005]

In recent years, switching power supplies have been required to have a large size and a large current due to a decrease in the operating voltage of the ICs and an increase in currents due to an increase in the degree of integration of the ICs (integrated circuits). I have. The loss due to the resistance of the conductor in the choke coil or the transformer, so-called copper loss, increases in proportion to the square of the current value. Therefore, in a planar coil or a planar transformer used as a choke coil or a transformer, reducing the resistance of the conductor is an important issue.

The number of turns (number of turns) of a winding in a choke coil or a transformer is determined by a ripple voltage and an input / output voltage ratio required for a switching power supply, as well as a power supply driving frequency, a core shape, physical properties, and the like. However, odd numbers of turns are often required. A printed coil has a higher degree of freedom in designing a winding than a coil using a wire. For example, in a printed coil, by changing the width of a conductor pattern, a winding having an arbitrary number of turns can be formed in a predetermined winding frame (a region where the conductor pattern is arranged). In a printed coil, a plurality of conductor patterns having the same pattern are stacked and connected in parallel using through holes or the like, so that the allowable current capacity can be adjusted.

Conventionally, the following four methods have been mainly used as a method of forming a winding having an odd number of turns of three or more in a planar coil or a planar transformer.
The first method is a method in which a required winding of odd turns is formed by a single conductor layer having a conductor pattern of odd turns. The second method is described in, for example,
As disclosed in Japanese Patent Application Laid-Open No. 5 (1999) -2005, this is a method in which odd-numbered conductor layers having one-turn conductor patterns are connected in series.
A third method is to connect a conductor layer having an even-numbered turn conductor pattern and a conductor layer having an odd-numbered turn conductor pattern in series. The fourth method is described in, for example,
As shown in FIGS. 6 to 9 of Japanese Patent Publication No. 0-163039, a conductor layer having a conductor pattern of [even number + α] turns (α is larger than 0 and smaller than 1) and [even number + (1
-Α)] is a method of connecting in series a conductor layer having a conductor pattern of turns.

However, in any of the above methods,
There were the following problems. In the first method, it is necessary to lead one terminal of the winding from near the inner peripheral edge of the conductor pattern. Therefore, in the first method, a core usually used for a planar coil, that is, a portion arranged to penetrate the winding (so-called middle foot) and a portion arranged on the outer peripheral side of the winding It is not possible to use a core that is wide so that the connection with the (so-called outer leg) covers most of the winding. In the case of using the first method, it is necessary to use a core having a narrow width of the connection portion as a core so that the connection portion does not hit a terminal of a winding derived from near the inner peripheral edge of the conductor pattern. There is.
In this case, it is necessary to increase the thickness of the core in order to secure a cross-sectional area of the core that does not saturate the magnetic flux. Therefore, the first method has a problem that it is difficult to reduce the thickness of the planar coil or the planar transformer.

In the second method, since the same number of conductor layers as the required number of turns are laminated, there is a problem that the planar coil or the planar transformer becomes thick. Also, the second
In the method of (1), as the number of turns required increases, the number of connection parts for connecting odd-numbered conductor layers in series is required. For example, when a 5-turn winding is formed, four connection parts other than terminals are required. Therefore, there is a problem that it is necessary to secure a wide area for arranging the connection part in the planar coil or the planar transformer. Further, in the second method, since the number of layers of the conductor layer matches the number of turns of the winding, there is a problem that the degree of freedom in designing the number of layers of the conductor layer is small. For example, when a five-turn winding is formed, the number of conductor layers is in units of five layers. That is, in this case, for example, to increase the number of conductor layers in order to increase the current capacity, the number of conductor layers must be a multiple of five.
Layering is not possible.

In the third method and the fourth method, the winding directions of the conductor patterns are reversed in the two conductor layers, and the inner ends of the two conductor patterns are electrically connected to each other, whereby the windings of the windings are formed. The two terminals can be led out from the outer ends of the two conductor patterns. Therefore, in the third method and the fourth method, since both terminals of the winding can be arranged outside the core, a thin core having a wide connecting portion between the middle foot and the outer foot is used. be able to. In the third method and the fourth method, the number of conductor layers can be designed in units of two layers, and the degree of freedom in designing the number of conductor layers is large.

However, in the third method and the fourth method, a portion where the width of the conductor pattern greatly differs occurs in the entire winding, and thus the current density changes depending on the winding portion. Therefore, in the third method and the fourth method,
From the viewpoint of reducing the loss, the optimum design of the conductor pattern cannot be made.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a planar coil and a planar transformer having odd-numbered turns of windings, which can be made thinner and have a reduced number of conductor layers. An object of the present invention is to provide a planar coil and a planar transformer having a large degree of freedom in design and low loss.

[0013]

The planar coil according to the present invention comprises:
A first conductor layer having an odd number of turns of winding formed by a flat conductor, having an insulating layer and a first conductor pattern formed by spirally disposing the flat conductor. A second conductor layer having a second conductor pattern formed by spirally arranging plate-shaped conductors, and a second conductor layer superposed on the first conductor layer via an insulating layer; And the second conductor pattern are respectively N
(N is an integer equal to or greater than 1) including a winding portion of +1 turn, and the innermost winding portions of the first conductor pattern and the second conductor pattern are connected in parallel to form the first conductor pattern. And 2N +
A one-turn winding is configured.

In the planar coil of the present invention, the innermost winding portions of the first conductor pattern and the second conductor pattern are connected in parallel, and these constitute a one-turn conductive path in the winding. . Further, a conductive path for 2N turns is formed by the other winding portions in the first conductor pattern and the second conductor pattern. In the present invention,
The first conductor pattern and the second conductor pattern can have similar patterns with respect to their width.
Also, in the present invention, the first conductor pattern and the innermost winding portion of the second conductor pattern may be configured as one conductor pattern.
The thickness of the conductive path for the turn is twice the thickness of the other conductive paths. By adjusting the width, the resistance value of the entire winding of 2N + 1 turns is reduced, and the loss in the entire winding is reduced. Can be reduced. Note that the present invention is not limited to the case where the first conductor layer and the second conductor layer are overlapped only with the insulating layer interposed therebetween. This includes the case where the second conductor layers are overlapped.

In the planar coil of the present invention, in the first conductor pattern and the second conductor pattern, the width of the innermost winding portion may be substantially half the width of the other winding portions. In this case, the first conductor pattern and the second conductor pattern
The thickness of one turn of the conductive path formed by the innermost winding portion of the conductive pattern of the second conductive pattern is twice the thickness of the other conductive path, but its width is substantially the width of the other conductive path. , The cross-sectional area is substantially equal to the cross-sectional area of the other conductive paths. Therefore, the current density in each part of the winding of 2N + 1 turns is equalized, and the loss in the winding is reduced.

In the present application, the winding portion refers to a portion corresponding to one turn in the conductor pattern. Further, in the present application, “substantially half” includes exactly half a value and a value including an allowable range error such as a rounding error in design or a manufacturing error. Meaning.

Further, in the planar coil of the present invention, in the first conductor pattern and the second conductor pattern, the inner peripheral portion of the winding portion of the n-th turn (n is an integer of 1 or more and N + 1 or less) from the inside is obtained. The radius is r _i (n), the radius of the outer circumference is r _o (n), the radius r _min of the inner circumference of the innermost winding portion, the radius of the outer circumference of the outermost winding portion and the innermost radius are Given the difference W _{total from} the radius of the inner peripheral part of the winding part and the distance D between the winding parts between adjacent turns, the value of A represented by the following equation (1) is minimum. R _i (n) and r _o (n) may be determined so that Where K (1) =
0.5, when n ≧ 2, K (n) = 2, r _i (1) = r _min , r _{i
(n + 1) -r o (} n) = D, r o (N + 1) -r i (1) is a = W _total.

[0018]

(Equation 3)

As described above, by setting r _i (n) and r _o (n) such that the value of A represented by the equation (1) is minimized, the resistance value of the entire winding of 2N + 1 turns is obtained. Is minimized, and consequently the losses in the entire winding are minimized.

In the planar coil of the present invention, a plurality of sets of insulating layers, a first conductive layer and a second conductive layer are laminated in the thickness direction, and the windings of each set are connected in parallel. Is also good.

A planar transformer according to the present invention has a primary winding and a secondary winding formed by conductors arranged in a plane, and at least one of the primary winding and the secondary winding is A first conductor layer having a first conductor pattern formed by spirally arranging plate-shaped conductors;
A second conductor layer having a second conductor pattern formed by spirally arranging flat conductors, and a second conductor layer superimposed on the first conductor layer via an insulating layer; The pattern and the second conductor pattern each include a winding portion of N (N is an integer of 1 or more) +1 turns, and the innermost winding portions of the first conductor pattern and the second conductor pattern are arranged in parallel. By being connected, a winding of 2N + 1 turns is constituted by the first conductor pattern and the second conductor pattern.

In the planar transformer of the present invention, the innermost winding portions of the first conductor pattern and the second conductor pattern are connected in parallel to each other, whereby the first conductor pattern and the second conductor pattern are connected in parallel.
A conductive path for the turn is formed. Further, a conductive path for 2N turns is formed by the other winding portions in the first conductor pattern and the second conductor pattern. According to the present invention, the first conductor pattern and the second conductor pattern can have the same pattern with respect to their width. In the present invention, the first conductor pattern and the second
The thickness of the conductive path for one turn constituted by the innermost winding portion of the conductor pattern of the above is twice the thickness of the other conductive paths, but by adjusting the width thereof, 2N + 1 turns of the conductive path can be obtained. By reducing the resistance value of the entire wire, it is possible to reduce the loss in the entire winding. Note that the present invention
This is not limited to the case where the first conductor layer and the second conductor layer are overlapped only via the insulating layer, and the first conductor layer and the second conductor layer are overlapped via other layers in addition to the insulating layer. Includes cases where

In the planar transformer of the present invention, in the first conductor pattern and the second conductor pattern, the width of the innermost winding portion may be substantially half the width of the other winding portions. In this case, the thickness of one turn of the conductive path formed by the innermost winding portions of the first conductive pattern and the second conductive pattern is two times the thickness of the other conductive paths.
Although doubled, its width is substantially half the width of the other conductive path, so that its cross-sectional area is substantially equal to the cross-sectional area of the other conductive path. Therefore, the current density in each part of the winding of 2N + 1 turns is equalized, and the loss in the winding is reduced.

Further, in the planar transformer according to the present invention, in the first conductor pattern and the second conductor pattern, the inner circumferential portion of the winding portion of the nth turn (n is an integer of 1 or more and N + 1 or less) from the inside is obtained. The radius is r _i (n) and the radius of the outer periphery is r _o (n)
The radius r _{min of} the inner periphery of the innermost winding portion, the difference W _total between the radius of the outer periphery of the outermost winding portion and the radius of the inner periphery of the innermost winding portion, and adjacent Given a distance D between winding portions between turns, r _i (n) is such that the value of A represented by the following equation (1) is minimized.
And r _o (n) may be defined. However, K (1)
= 0.5, when n ≧ 2, K (n) = 2, r _i (1) = r _min ,
_{r i (n + 1) -r} o (n) = D, is a _{r o (N + 1) -r} i (1) = W total.

[0025]

(Equation 4)

As described above, by setting r _i (n) and r _o (n) such that the value of A expressed by the equation (1) is minimized, the resistance value of the entire winding of 2N + 1 turns is obtained. Is minimized, and consequently the losses in the entire winding are minimized.

[0027]

Embodiments of the present invention will be described below in detail with reference to the drawings. [First Embodiment] First, the configuration of a planar coil according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a plan view showing a first conductor layer and an insulating layer thereunder in the planar coil according to the present embodiment. FIG. 2 is a plan view showing an insulating layer in the planar coil according to the present embodiment. FIG. 4 is a plan view showing a second conductor layer in the planar coil according to the present embodiment, and FIG. 4 is a cross-sectional view showing an enlarged cross section taken along line AA in FIG.

The planar coil according to the present embodiment has a rectangular plate-shaped insulating layer 10, a first conductor layer 11 formed on one surface (upper surface) of the insulating layer 10, And a second conductor layer 12 formed on the other surface (lower surface). As described above, the first conductor layer 11 and the second conductor layer 12 are overlapped with the insulating layer 10 interposed therebetween.

In the vicinity of one side of the insulating layer 10, there is provided a terminal region 10b in which terminals of the winding are arranged. A circular hole 10a is formed in a central portion of a portion of the insulating layer 10 excluding the terminal region 10b. A core (magnetic core) can be inserted into the hole 10a.

As shown in FIG. 1, the first conductor layer 11
Has a first conductor pattern 11a formed by spirally arranging flat conductors including a foil shape. For example, copper is used as the conductor. Similarly, as shown in FIG. 3, the second conductor layer 12 has a second conductor pattern 12a formed by spirally arranging flat conductors including a foil shape. The first conductor pattern 11a and the second
The conductor pattern 12a is formed between the outer peripheral portion of the hole 10a and the insulating layer 1.
0 is arranged in a region between the outer peripheral portion of the first portion and the outer peripheral portion.

The planar coil according to the present embodiment may be manufactured, for example, by etching each conductor layer on a double-sided printed circuit board having conductor layers formed on both sides of an insulating substrate, or by punching a conductor plate. It may be manufactured.
Further, it may be manufactured by a thin film forming technique such as a sputtering method.

The first conductor pattern 11a and the second conductor pattern 12a are respectively N (N is an integer of 1 or more) +1
Includes turn windings. In the present embodiment, in particular, N = 1. That is, the first conductor pattern 11a and the second conductor pattern 12a each include a two-turn winding portion.

The first conductor pattern 11a and the second conductor pattern 12a have opposite conductor winding directions.
That is, as shown in FIG.
1a, the conductor is wound clockwise from the inside to the outside, and as shown in FIG.
In 2a, the conductor is wound in a counterclockwise direction from the inside to the outside.

As shown in FIG. 1, the outer end of the first conductor pattern 11a is located on the right side in the terminal region 10b of the insulating layer 10. On one surface (upper surface) of the insulating layer 10, a terminal layer 13 used as a terminal is provided at a position on the left side in the terminal region 10b.

As shown in FIG. 3, the outer end of the second conductor pattern 12a is located at the left side in the terminal region 10b of the insulating layer 10. On the other surface (lower surface) of the insulating layer 10, a terminal layer 14 used as a terminal is provided at a position on the right side in the terminal region 10b.

At the left position in the terminal region 10b,
Terminal layer 13, insulating layer 10, and second conductor pattern 1
A through hole 15 penetrating the outer end of 2a is formed. Through this through hole 15, the terminal layer 13 is formed.
And the outer end of the second conductor pattern 12a are electrically connected.

At the right side position in the terminal area 10b,
A through hole 16 penetrating the outer end of the first conductor pattern 11a, the insulating layer 10, and the terminal layer 14 is formed. Through the through hole 16, the outer end of the first conductor pattern 11a and the terminal layer 14 are electrically connected.

As shown in FIGS. 1 and 3, the innermost winding portions of the first conductor pattern 11a and the second conductor pattern 12a are connected to the conductor patterns 11a, 12a.
And through holes 17, 18 penetrating through the insulating layer 10. These form a one-turn conductive path in the winding. The through holes 17 and 18 are provided at both ends of the innermost winding portion of each of the conductor patterns 11a and 12a. Further, 2N = 2 due to other winding portions in the first conductor pattern 11a and the second conductor pattern 12a.
A conductive path for the turn is formed. Thus, the first
Conductor pattern 11a and second conductor pattern 12a
Thus, a winding of 2N + 1 = 3 turns is formed.

In the present embodiment, as shown in FIGS. 1 and 3, the first conductor pattern 11a and the second conductor pattern 12a can have the same pattern with respect to their width. . Therefore, according to the present embodiment, it is possible to prevent a location where the width of the conductor pattern is greatly different from occurring, except for the relationship between the innermost winding part and the other winding parts. In the present embodiment, the thickness of one turn of the conductive path formed by the innermost winding portions of the first conductive pattern 11a and the second conductive pattern 12a is twice the thickness of the other conductive paths. However, by adjusting the width, the resistance value of the entire winding can be reduced, and the loss in the entire winding can be reduced.

In this embodiment, in particular, FIGS.
As shown in the figure, the first conductor pattern 11a and the second
In the conductor pattern 12a, the width of the innermost winding portion is substantially half the width of the other winding portions. The width of the other windings is constant. The thickness of one turn of the conductive path formed by the innermost winding portions of the first conductive pattern 11a and the second conductive pattern 12a is twice the thickness of the other conductive paths, but the width thereof is Is substantially half the width of the other conductive path, so that its cross-sectional area is substantially equal to the cross-sectional area of the other conductive path. Therefore, according to the planar coil according to the present embodiment, the current density in each part of the three-turn winding is made uniform, and the loss in the winding is reduced.

According to the present embodiment, a three-turn winding can be constituted by the two conductor layers 11 and 12. Further, according to the present embodiment, the two terminals of the winding can be led out from the outer ends of the two conductor patterns 11a and 12a. Therefore, since both terminals of the winding can be arranged outside the wide core, a thin core having a wide connecting portion between the middle foot and the outer foot can be used.
For these reasons, according to the present embodiment, it is possible to reduce the thickness of the planar coil.

According to the present embodiment, the conductor layer 1
The number of layers 1 and 12 can be designed in units of two layers, and the degree of freedom in designing the number of layers of the conductor layers 11 and 12 increases.

[Second Embodiment] Next, a configuration of a planar coil according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a plan view showing a first conductor layer and an insulating layer thereunder in the planar coil according to the present embodiment, and FIG. 6 is a plan view showing a second conductor layer in the planar coil according to the present embodiment. It is.

The configuration of the planar coil according to this embodiment is as follows.
This is the same as the planar coil according to the first embodiment except that the shapes of the conductor patterns 11a and 12a are different.

In the planar coil according to the present embodiment, the first
Conductor pattern 11a and second conductor pattern 12a
, The radius of the inner peripheral portion of the winding portion of the n-th turn (n is an integer of 1 or more and N + 1 or less) from the inner side is r _i (n), the radius of the outer peripheral portion is r _o (n), The radius r _min of the inner circumference of the winding portion, the difference W _total between the radius of the outer circumference of the outermost winding portion and the radius of the inner circumference of the innermost winding portion, and the winding between adjacent turns R _i (n) and r _o (n) are determined so that the value of A represented by the following equation (1) is minimized when the distance D between the parts is given. However, when K (1) = 0.5 and n ≧ 2, K (n) = 2 and r _i (1)
= R _min , r _i (n + 1)-r _o (n) = D, r _o (N + 1)-r _i (1) =
W _total . Logx is the natural logarithm of x.

[0046]

(Equation 5)

In the present embodiment, A represented by the equation (1)
By setting r _i (n) and r _o (n) to minimize the value of, the resistance of the entire winding of 2N + 1 turns is minimized, and as a result, the loss in the entire winding is minimized. Become. Hereinafter, this will be described in detail.

First, thickness t, inner radius r, outer radius r + dr
Consider a ring-shaped conductor pattern of FIG. If the width dr is sufficiently small, the resistance value of this conductor pattern is (2πr
× ρ) / (t × dr). Here, ρ is the volume resistivity of the conductor. Therefore, the conductance of the conductor pattern, that is, the reciprocal of the resistance value is (t × dr) / (2π
r × ρ).

Inner radius r_i, Outer radius r_oRing-shaped conductor
The turn has a ring shape with a small width dr as described above.
When the conductor patterns are equivalent to those connected in parallel
Conceivable. Therefore, thickness t, inner radius r_i, Outer radius r_oof
The conductance of the ring-shaped conductor pattern is calculated by the following equation.
As in (2), (t × dr) / (2πr × ρ) is represented by r _i
~ R_oBy integrating over the range
You.

[0050]

(Equation 6)

The thickness t, an inner radius r _i, the resistance value R of the ring-shaped conductor pattern of the outer radius r _o, since the reciprocal of the conductance of the conductor pattern, represented by the following formula (3).

[0052]

(Equation 7)

Here, it is assumed that 2πρ / t = B. The resistance value R of the conductive path for one turn formed by the innermost winding portions of the first conductor pattern 11a and the second conductor pattern 12a is represented by the following equation (4).

[0054]

(Equation 8)

On the other hand, the sum R of the resistance per turn of the other winding part of the first conductor pattern 11a and the resistance per turn of the other winding part of the second conductor pattern 12a is: It is represented by the following equation (5).

[0056]

(Equation 9)

Therefore, the resistance value R _{total of the} entire winding of 2N + 1 turns is expressed by the following equation (6).

[0058]

(Equation 10)

Accordingly, in the first conductor pattern 11a and the second conductor pattern 12a, the inner radius r _min of the innermost winding portion, the outer radius of the outermost winding portion, and the inner radius rmin of the innermost winding portion. Given the difference W _{total from the} radius and the distance D between the winding portions between adjacent turns, to minimize the resistance of the entire winding of 2N + 1 turns, the above equation (1) is used. It is sufficient to set r _i (n) and r _o (n) such that the value of A represented is minimized.

The values of r _i (n) and r _o (n) that minimize the value of A are difficult to obtain analytically, but can be obtained by numerical calculation using a computer.

In the present embodiment, in particular, N = 1, and the first conductor pattern 11a and the second conductor pattern 12a constitute a three-turn winding.

According to the planar coil of this embodiment,
Since r _i (n) and r _o (n) are set so that the value of A represented by the equation (1) is minimized, the resistance value of the entire winding can be minimized. Therefore, according to the present embodiment, the windings can be arranged such that the loss is minimized in the limited space, and as a result, the loss due to the resistance of the conductor can be reduced.

Other configurations, operations and effects of the present embodiment are the same as those of the first embodiment.

Next, an example of the planar coil according to the first embodiment (hereinafter referred to as a first example) and an example of the planar coil according to the second embodiment (hereinafter referred to as a second example) will be described. ), And the results of comparing the calculated resistance values of the planar coil of each embodiment and the planar coils of the two comparative examples.

FIG. 7 is a plan view showing the first conductor layer and the insulating layer thereunder in the planar coil of the first comparative example. FIG. 8 is a plan view showing the second conductor layer of the planar coil of the first comparative example. FIG. The planar coil of the first comparative example has an insulating layer 1
10 and a first conductor layer 111 and a second conductor layer 112 formed on each surface of the insulating layer 110. The first conductor layer 111 has a first conductor pattern 111a, and the second conductor layer 112 has a second conductor pattern 112a.
have. The first conductor pattern 111a has a two-turn winding portion, and the second conductor pattern 112a has a one-turn winding portion. First conductor pattern 11
The winding direction of the conductor is reversed between 1a and the second conductor pattern 112a. Conductor patterns 111a, 112a
Are electrically connected to each other through a through hole 117. Thus, the conductor pattern 1
A three-turn winding is constituted by 11a and 112a.

FIG. 9 is a plan view showing the first conductor layer and the insulating layer thereunder in the planar coil of the second comparative example.
FIG. 9 is a plan view showing a second conductor layer in the planar coil of the second comparative example. The planar coil of the second comparative example includes an insulating layer 120, and a first conductor layer 121 and a second conductor layer 122 formed on each surface of the insulating layer 120.
The first conductor layer 121 has a first conductor pattern 121a, and the second conductor layer 122 has a second conductor pattern 122a.
have. The first conductor pattern 121a has a 1.5-turn winding portion, and the second conductor pattern 122a also has a 1.5-turn winding portion. The first conductor pattern 121a and the second conductor pattern 122a have opposite conductor winding directions. The conductor patterns 121a,
Ends on the inner side of 122a are electrically connected to each other through through holes 127. Thus, a three-turn winding is constituted by the conductor patterns 121a and 122a.

In each of the planar coils of the first embodiment, the second embodiment, the first comparative example, and the second comparative example, copper is used as a conductor constituting a winding, and the thickness t of the conductor is adjusted. 0.
06 mm, the inner radius r _min of the innermost winding portion is 6.4.
mm, the difference W _total between the outer radius of the outermost winding portion and the inner radius of the innermost winding portion was 5.1 mm, and the distance D between the winding portions between adjacent turns was 0.2 mm.
Under these conditions, for each planar coil, the inner radius r _i (n) and the outer radius r _o (n) of the winding portion for each turn were determined, and the resistance value R _{total of the} entire winding was determined. The volume resistivity of copper was 1.72 × 10 ⁻⁸ (Ωm). Also,
Below, the width r _o a _{(n) -r i (n)} W of the winding portions of each turn
(n).

The width W (n) of the winding portion for each turn and the resistance value R _{total of the} entire winding in each of the planar coils of the first embodiment, the second embodiment, and the first comparative example are as follows. It is as shown in the table below. In the table, the first conductor layer is described as layer A, and the second conductor layer is described as layer B. In the planar coil of the second comparative example, in W _total , the ratio of the width of the part forming the conductive path for two turns to the width of the part forming the conductive path for one turn is the second. The resistance value is the same as that of the first comparative example because it is the same as that of the first comparative example.

[0069]

[Table 1]

As can be seen from the above table, in the planar coil of the first embodiment, the resistance R _{total of the} entire winding
8.71% reduction compared to the planar coil of the comparative example.
Further, in the planar coil of the second embodiment, the resistance value R _{total of the} entire winding is set to be 1 compared with the planar coil of the first comparative example.
It can be reduced by 0.45%.

Incidentally, in the first embodiment, the width W (1) of the inner winding portion is 0.5 times the width W (2) of the outer winding portion. Further, in the second embodiment, the width W (n) of the winding portion for each turn is determined so that the value of A represented by Expression (1) is minimized. The width W (1) of the inner winding portion is 0.3 times the width W (2) of the outer winding portion.
7 times. However, the width W (2) of the outer winding portion
Ratio of the width W (1) of the inner winding part to W (1) / W (2)
Is not 0.5 or 0.37, the resistance R of the entire winding is
It is possible to reduce the _total as compared with the planar coil of the first comparative example. This will be described with reference to FIGS.

FIG. 11 shows the width W of the winding portion for each turn.
Conditions other than (1) and W (2) are the same as those of the first embodiment, the second embodiment, and the first comparative example, and the winding when W (1) / W (2) is changed. the overall resistance value R _total, is a representation in a ratio in the graph to the resistance value R _total of the whole winding in the first comparative example. From FIG. 11, it can be seen that under the above conditions, the ratio of the resistance values is 1 or less in a wide range of W (1) / W (2) from 0.18 to 0.75. Therefore, in this case, W (1) / W ( 2) is greater than 0.18, with less than 0.75 range, to reduce the resistance value _{R-to tal} of the entire winding than in the first comparative example be able to.

W (1) / W at which the ratio of the resistance values becomes 1 or less
The range of (2) varies depending on the values of r _min , W _total and D. For example, consider a case where r _min is 3 mm and other conditions are the same as when the graph of FIG. 11 was obtained. Further, as a comparative example in this case, r _min was set to 3
Except for mm, the same thing as in the first comparative example is considered. In this case, the resistance value _Rtotal of the entire winding in the comparative example of the resistance value _Rtotal of the entire winding when W (1) / W (2) is changed.
FIG. 12 shows a graph of the ratio to the _total . In this case, from FIG. 12, W (1) / W
It can be seen that in the case of (2) in a wide range from 0.13 to 0.68, the ratio of the resistance values becomes 1 or less. Therefore, in this case, W (1) / W (2) is larger than 0.13 and 0.68
Within a smaller range, the resistance R of the entire winding is smaller than that of the comparative example.
_total can be reduced.

As described above, in the present invention, the width of the innermost winding portion is substantially half the width of the other winding portions with respect to the width of the first conductor pattern and the second conductor pattern. 11 and FIG. 12 are not limited to the case where r _i (n) and r _o (n) are determined so that the value of A represented by the equation (1) is minimized. In such a wide range, the resistance value R _{total of the} entire winding can be reduced.

[Third Embodiment] Next, a configuration of a planar coil according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 13 is a plan view showing a first conductor layer and an insulating layer thereunder in the planar coil according to the present embodiment. FIG. 14 is a plan view showing an insulating layer in the planar coil according to the present embodiment. FIG. 16 is a plan view showing a second conductor layer in the planar coil according to the present embodiment, and FIG. 16 is a cross-sectional view showing an enlarged cross section taken along line BB in FIG.

In the planar coil according to the present embodiment, N =
It is 2. That is, the first conductor pattern 11a and the second conductor pattern 12a each include a three-turn winding portion. Then, the first conductor pattern 11a
And 2N + 1 = 5 by the second conductor pattern 12a.
A turn winding is configured. First conductor pattern 1
In 1a and the second conductor pattern 12a, the width of the innermost winding portion is substantially half the width of the other winding portions. The width of the other windings is constant. Other configurations, operations, and effects of the present embodiment are the same as those of the first embodiment.

[Fourth Embodiment] Next, the configuration of a planar coil according to a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 17 is a plan view showing a first conductor layer and an insulating layer thereunder in the planar coil according to the present embodiment, and FIG. 18 is a plan view showing a second conductor layer in the planar coil according to the present embodiment. It is.

The configuration of the planar coil according to this embodiment is as follows.
This is the same as the planar coil according to the third embodiment except that the shapes of the conductor patterns 11a and 12a are different.

In the planar coil according to this embodiment, the second
In the first conductor pattern 11a and the second conductor pattern 12a, the radius of the inner peripheral portion of the n-th turn (n is an integer of 1 or more and N + 1 or less) from the inside in the first conductor pattern 11a and the second conductor pattern 12a is r _i (n), the radius of the outer circumference is r _o (n), the radius r _min of the inner circumference of the innermost winding, the radius of the outer circumference of the outermost winding, and the innermost winding Given the difference W _{total from} the radius of the inner periphery of the portion and the distance D between the winding portions between adjacent turns, the value of A represented by equation (1) is minimized. r _i (n) and r _o (n) are defined.

The other structures, operations and effects of the present embodiment are the same as those of the second or third embodiment.

Next, an example of the planar coil according to the third embodiment (hereinafter, referred to as a third example) and an example of the planar coil according to the fourth embodiment (hereinafter, referred to as a fourth example). ), And the result of comparing the resistance values obtained by calculation between the planar coil of each embodiment and the planar coil of the third comparative example.

FIG. 19 is a plan view showing the first conductor layer and the insulating layer thereunder in the planar coil of the third comparative example.
0 is a plan view showing a second conductor layer in the planar coil of the third comparative example. The planar coil of the third comparative example includes an insulating layer 110 and first insulating layers 110 formed on each surface of the insulating layer 110.
, And a second conductor layer 112. The first conductor layer 111 has a first conductor pattern 111a.
And the second conductor layer 112 has the second conductor pattern 11
2a. The first conductor pattern 111a has a three-turn winding portion, and the second conductor pattern 112a has a two-turn winding portion. The conductor winding directions of the first conductor pattern 111a and the second conductor pattern 112a are opposite. Conductive patterns 111a, 11
The inner ends of 2a are electrically connected via a through hole 117. In this way, a five-turn winding is constituted by the conductor patterns 111a and 112a.

In each of the planar coils of the third embodiment, the fourth embodiment, and the third comparative example, copper is used as a conductor constituting the winding, the thickness t of the conductor is 0.06 mm, and The inner radius r _min of the winding portion is 6.4 mm, the difference W _total between the outer radius of the outermost winding portion and the inner radius of the innermost winding portion is 5.1 mm, and the winding between adjacent turns is The distance D between the portions was 0.2 mm. Under these conditions, for each planar coil, the inner radius r _i (n) and the outer radius r _o (n) of the winding portion for each turn were determined, and the resistance value R _{total of the} entire winding was determined. The volume resistivity of copper was 1.72 × 10 ⁻⁸ (Ωm). In addition, the following represents the width r _o of the winding portion of each turn a (n) -r _i (n) with W (n).

The width W (n) of the winding portion for each turn and the resistance value R _{total of the} entire winding in each of the planar coils of the third embodiment, the fourth embodiment, and the third comparative example are as follows. It is as shown in the table below. In the table, the first conductor layer is described as layer A, and the second conductor layer is described as layer B.

[0085]

[Table 2]

As can be seen from the above table, in the planar coil of the third embodiment, the resistance R _{total of the} entire winding
2.12% reduction compared to the planar coil of the comparative example.
Further, in the planar coil of the fourth embodiment, the resistance value R _{total of the} entire winding is set to _4.about .
It can be reduced by 35%. The first conductor pattern and the second conductor pattern each have a winding portion of 2.5 turns, and the resistance value of the entire winding in the planar coil forming the winding of 5 turns by these is the third winding. This is equivalent to the comparative example.

[Fifth Embodiment] Next, the configuration of a planar coil according to a fifth embodiment of the present invention will be described with reference to FIGS. 21 is a plan view of the planar coil according to the present embodiment, FIG. 22 is a right side view of the planar coil shown in FIG. 21, and FIG.
It is sectional drawing which expanded and represented the cross section shown by the line. FIG. 24 is a plan view showing a core of the planar coil according to the present embodiment, and FIG. 25 is a side view of this core.

In the planar coil according to this embodiment, the first
Alternatively, the insulating layer 10, the first conductor layer 11, and the second conductor layer 12 in the second embodiment are set as one set, and three sets are stacked in the thickness direction, and the windings of each set are connected in parallel. Connected. The planar coil according to the present embodiment has three stacked insulating layers 10, a first conductive layer 11, and a second conductive layer 1.
2 and a plurality of E-shaped cores 21A and 21B mounted on the laminated body 20.

As shown in FIGS. 21 and 22, the terminal region 10b is located outside the cores 21A and 21B. The windings of each set in the laminate 20 have the through holes 1
5 and 16 are connected in parallel. As shown in FIG. 22, for example, a terminal 22 is inserted into the through holes 15 and 16.

As shown in FIG. 23, the E-shaped cores 21A and 21B are formed such that the central projections are formed in the holes 1 of the insulating layer 10.
0a.

The other configurations, operations and effects of this embodiment are the same as those of the first or second embodiment.

[Sixth Embodiment] Next, the configuration of a planar coil according to a sixth embodiment of the present invention will be described with reference to FIG. FIG. 26 is a sectional view of the planar coil according to the present embodiment. In the planar coil according to the present embodiment, the following laminated body 20 is provided instead of the laminated body 20 in the fifth embodiment. That is,
In the present embodiment, the insulating layer 10, the first conductor layer 11, and the second conductor layer 1 in the third or fourth embodiment are described.
2 is one set, and three sets are stacked in the thickness direction, and the windings of each set are connected in parallel to form a stacked body 20.

As an example (hereinafter, referred to as a fifth example) of the planar coil according to the present embodiment, three sets of the planar coils of the third example are stacked, and the windings of each set are arranged in parallel. And a laminated body 20 was manufactured as a prototype. When the resistance value of the entire winding in the planar coil of the fifth example produced as a trial was measured, it was 15.05 mΩ.

As a comparative example (hereinafter, referred to as a fourth comparative example) with respect to the fifth embodiment, three sets of planar coils of the third comparative example are stacked, and the windings of each set are arranged in parallel. A prototype in which the laminate 220 was connected to each other was manufactured. FIG. 27 is a cross-sectional view of the planar coil of the fourth comparative example. In the planar coil of the fourth comparative example, the configuration other than the laminated body 220 is the same as that of the fifth embodiment. When the resistance value of the entire winding in the planar coil of the fourth comparative example was measured, it was 15.3.
It was 8 mΩ.

Therefore, the reduction ratio of the resistance value of the planar coil of the fifth embodiment to the planar coil of the fourth comparative example is 2.1.
5%, which is equivalent to the reduction rate of the resistance value of the planar coil of the third embodiment with respect to the planar coil of the third comparative example.

Other configurations, operations and effects of the present embodiment are the same as those of the third, fourth or fifth embodiment.

[Seventh Embodiment] Next, a seventh embodiment of the present invention will be described.
The configuration of the planar transformer according to the embodiment will be described. FIG. 28 is a plan view of the plane transformer according to the present embodiment, FIG. 29 is a right side view of the plane transformer shown in FIG.
FIG. 30 is an enlarged cross-sectional view of a cross-section indicated by line DD in FIG. The planar transformer according to the present embodiment has a primary winding and a secondary winding formed by conductors arranged in a plane. As shown in FIGS. 28 to 30, the planar transformer according to the present embodiment includes a laminate 30 in which a plurality of conductor layers and a plurality of insulating layers are alternately laminated, and which is mounted on the laminate 30. E-shaped cores 21A and 21B.

As shown in FIGS. 28 and 29, the laminate 30 has terminal regions 31 and 32. Terminal area 3
The reference numerals 1 and 32 are arranged at positions opposite to each other and outside the cores 21A and 21B. Terminal area 31
Are provided with through holes 33 and 34, and the terminal region 32
Are provided with through holes 35 and 36. FIG.
As shown in (1), for example, a terminal 37 is inserted into the through holes 33 and 34, and a terminal 38 is inserted into the through holes 35 and 36.

Further, as shown in FIG. 30, the E-shaped cores 21A and 21B are formed such that the central convex portions have insulating layers 4 to be described later.
It is arranged so that it may butt through the 0 hole 40a.

The laminate 30 includes a PA layer, a PB layer, a SA layer,
It has four types of conductor layers, ie, SB layers, and an insulating layer 40. Each of the four types of conductor layers has a conductor pattern formed by spirally arranging flat conductors including a foil shape. The PA layer and the PB layer constitute a 5-turn primary winding, and the SA layer and the SB layer constitute a 2-turn secondary winding.
Therefore, the winding ratio of the planar transformer according to the present embodiment is 5: 2.

FIG. 31 is a plan view showing a PA layer and an insulating layer 40 thereunder, FIG. 32 is a plan view showing a PB layer and an insulating layer 40 therebelow, and FIG. 33 is an SA layer and an insulating layer thereunder. FIG. 34 is a plan view showing the SB layer and the insulating layer 40 thereunder, and FIG. 35 is a plan view of the insulating layer 40.

As shown in FIG. 31, the PA layer has a first conductive pattern 11 similar to that of the third or fourth embodiment.
a. As shown in FIG. 32, the PB layer has a second conductor pattern 12a similar to that of the third or fourth embodiment. That is, the first conductor pattern 1
1a and the second conductor pattern 12a each include a three-turn winding portion. The winding directions of the conductors of the first conductor pattern 11a and the second conductor pattern 12a are reversed. Also, the innermost winding portions of the first conductor pattern 11a and the second conductor pattern 12a are:
They are connected in parallel by through holes 17 and 18 penetrating the conductor patterns 11a and 12a and the insulating layer 40.
Therefore, the first conductor pattern 11a and the second conductor pattern 12a form a five-turn primary winding.

As shown in FIG. 31, the outer end of the first conductor pattern 11a is connected to the through hole. Insulating layer 4 provided with first conductor pattern 11a
0, the through holes 33, 35, 36 respectively
Are provided.

As shown in FIG. 32, the outer end of the second conductor pattern 12a is connected to the through hole 33. Insulating layer 4 provided with second conductor pattern 12a
0, the through holes 34, 35, 36 respectively
Are provided.

As shown in FIGS. 33 and 34, the SA layer
The SB layer has conductor patterns 51a and 52a, respectively. Each of the conductor patterns 51a and 52a has a one-turn winding portion. Conductive patterns 51a, 5
In 2a, the winding direction of the conductor is reversed. One end of the conductor pattern 51a is connected to the through hole 35. On the surface of the insulating layer 40 provided with the conductor pattern 51a, terminal layers 13, 14, 46 connected to the through holes 33, 34, 36, respectively, are provided. One end of the conductor pattern 52a is connected to the through hole 36. Insulating layer 4 provided with conductor pattern 52a
0, through holes 33, 34, 35, respectively.
Are provided with terminal layers 13, 14, 45 connected to. The other ends of the conductor patterns 51a and 52a are
They are electrically connected via through holes 53 penetrating through the conductor patterns 51a and 52a and the insulating layer 40.
In this way, a two-turn secondary winding is formed by the conductor patterns 51a and 52a.

As shown in FIG. 35, a circular hole 40a is formed in the center of the insulating layer 40. Each conductor pattern is arranged in a region between the outer peripheral portion of the hole 40a and the outer peripheral portion of the insulating layer 40. In the insulating layer 40, the above-described through holes 17, 18, 33 to 36, and 53 are formed.

The order of lamination of the PA layer, the PB layer, the SA layer, and the SB layer is, from the bottom, SA layer-PA layer-SB layer-PB layer-
SA layer-PA layer-SB layer-SA layer-PB layer-SB layer-P
The order is A layer-SA layer-PB layer-SB layer.

Examples of the planar transformer according to the present embodiment (hereinafter, referred to as a sixth example) include a PA layer and a PB.
The layers each having the first conductor pattern 11a and the second conductor pattern 12a in the third embodiment are used, the thickness of the insulating layer 40 is set to 0.1 mm, and the cores 21A and 21B made of ferrite are used. A prototype was used. About the prototyped planar transformer of the sixth embodiment, 200
When the winding resistance as viewed from the primary side at kHz was measured, it was 36.82 mΩ.

As a comparative example (hereinafter, referred to as a fifth comparative example) with respect to the sixth embodiment, the first conductor pattern 111a and the third conductor pattern in the third comparative example are respectively provided on the PA layer and the PB layer. 2 having a conductor pattern 112a, and the insulating layer 40 having a thickness of 0.1 mm.
30 and a ferrite core 21A, 2A.
A prototype using 1B was produced. FIG. 36 is a sectional view of the planar transformer of the fifth comparative example. This prototype 5
The winding resistance as viewed from the primary side at 200 kHz was measured for the planar transformer of the comparative example of 37.8.
It was 1 mΩ.

Therefore, the plane transformer of the sixth embodiment is 200 kHz higher than the plane transformer of the fifth comparative example.
The high frequency resistance at z was reduced by 2.6%.

In the present embodiment, the primary winding is odd-numbered turns (5 turns), and the secondary winding is even-numbered turns (2 turns). The next winding may have an odd number of turns. Alternatively, both the primary winding and the secondary winding may have odd-numbered turns.

Other structures, operations and effects of the present embodiment are the same as those of the third or fourth embodiment.

The present invention is not limited to the above embodiments, and various changes can be made. For example, the number of turns of a winding or a conductor pattern and the number of conductor layers are not limited to those described in the embodiment, and can be set arbitrarily.

The present invention can also be applied to a planar transformer in which one of the primary winding and the secondary winding is formed of a conductor other than a flat plate, for example, a round conductor.

[0115]

As described above, in the planar coil according to any one of claims 1 to 4 or the planar transformer according to any one of claims 5 to 7,
In the first conductor pattern and the second conductor pattern including the +1 turn winding part, the innermost winding parts of the first conductor pattern and the second conductor pattern are connected in parallel to each other, so that the 2N + 1 turn It constitutes a winding. Therefore, in the present invention, the first conductive pattern and the second conductive pattern
Can be made similar patterns with respect to their width. Further, in the present invention, the thickness of one turn of the conductive path formed by the innermost winding portions of the first conductive pattern and the second conductive pattern is twice the thickness of the other conductive paths. However, by adjusting the width, it is possible to reduce the resistance value of the entire winding of 2N + 1 turns, thereby reducing the loss of the entire winding. From the above, according to the present invention, it is possible to reduce the thickness of a planar coil or a planar transformer, increase the degree of freedom in designing the number of conductor layers, and further reduce the loss. It works.

Further, in the planar coil according to the second aspect or the planar transformer according to the sixth aspect, in the first conductor pattern and the second conductor pattern, the width of the innermost winding portion is substantially changed to other windings. It is half the width of the line. Therefore, according to the present invention, the current density in each part of the 2N + 1 turn winding can be made uniform, and as a result, there is an effect that the loss in the winding can be further reduced.

Further, in the planar coil according to the third aspect or the planar transformer according to the seventh aspect, in the first conductor pattern and the second conductor pattern, the value of A represented by the equation (1) is minimized. R _i (n) and r _o (n) are set as follows. Therefore, according to the present invention, it is possible to minimize the resistance value of the entire winding of 2N + 1 turns, and as a result, it is possible to minimize the loss in the entire winding.

[Brief description of the drawings]

FIG. 1 is a plan view showing a first conductor layer and an insulating layer thereunder in a planar coil according to a first embodiment of the present invention.

FIG. 2 is a plan view showing an insulating layer in the planar coil according to the first embodiment of the present invention.

FIG. 3 is a plan view showing a second conductor layer in the planar coil according to the first embodiment of the present invention.

FIG. 4 is an enlarged cross-sectional view of a cross-section indicated by line AA in FIG. 1;

FIG. 5 is a plan view showing a first conductor layer and an insulating layer therebelow in a planar coil according to a second embodiment of the present invention.

FIG. 6 is a plan view showing a second conductor layer in the planar coil according to the second embodiment of the present invention.

FIG. 7 is a plan view showing a first conductor layer and an insulating layer thereunder in a planar coil of a first comparative example.

FIG. 8 is a plan view showing a second conductor layer in the planar coil of the first comparative example.

FIG. 9 is a plan view showing a first conductor layer and an insulating layer therebelow in a planar coil of a second comparative example.

FIG. 10 is a plan view showing a second conductor layer in the planar coil of the second comparative example.

FIG. 11 shows an example of a change in the ratio between the resistance value of the entire winding in the present invention and the resistance value of the entire winding in the comparative example when the width of the winding portion for each turn is changed in the present invention. It is a characteristic diagram.

FIG. 12 shows another example of a change in the ratio between the resistance value of the entire winding in the present invention and the resistance value of the entire winding in the comparative example when the width of the winding portion for each turn is changed in the present invention. FIG.

FIG. 13 is a plan view showing a first conductor layer and an insulating layer therebelow in a planar coil according to a third embodiment of the present invention.

FIG. 14 is a plan view showing an insulating layer in a planar coil according to a third embodiment of the present invention.

FIG. 15 is a plan view showing a second conductor layer in the planar coil according to the third embodiment of the present invention.

FIG. 16 is an enlarged cross-sectional view illustrating a cross section indicated by line BB in FIG. 13;

FIG. 17 is a plan view showing a first conductor layer and an insulating layer therebelow in a planar coil according to a fourth embodiment of the present invention.

FIG. 18 is a plan view showing a second conductor layer in the planar coil according to the fourth embodiment of the present invention.

FIG. 19 is a plan view showing a first conductor layer and an insulating layer thereunder in a planar coil of a third comparative example.

FIG. 20 is a plan view showing a second conductor layer in the planar coil of the third comparative example.

FIG. 21 is a plan view of a planar coil according to a fifth embodiment of the present invention.

FIG. 22 is a right side view of the planar coil shown in FIG. 21.

FIG. 23 is an enlarged cross-sectional view of a cross-section indicated by line CC in FIG. 21;

FIG. 24 is a plan view showing a core in a planar coil according to a fifth embodiment of the present invention.

FIG. 25 is a side view of a core in a planar coil according to a fifth embodiment of the present invention.

FIG. 26 is a sectional view of a planar coil according to a sixth embodiment of the present invention.

FIG. 27 is a sectional view of a planar coil of a fourth comparative example.

FIG. 28 is a plan view of a planar transformer according to a seventh embodiment of the present invention.

FIG. 29 is a right side view of the planar transformer shown in FIG. 28.

FIG. 30 is an enlarged cross-sectional view of a cross-section indicated by line DD in FIG. 28;

FIG. 31 is a plan view showing a PA layer and an insulating layer thereunder in a planar transformer according to a seventh embodiment of the present invention.

FIG. 32 is a plan view showing a PB layer and an insulating layer thereunder in a planar transformer according to a seventh embodiment of the present invention.

FIG. 33 is a plan view showing an SA layer and an insulating layer thereunder in a planar transformer according to a seventh embodiment of the present invention.

FIG. 34 is a plan view showing an SB layer and an insulating layer thereunder in a planar transformer according to a seventh embodiment of the present invention.

FIG. 35 is a plan view of an insulating layer in a planar transformer according to a seventh embodiment of the present invention.

FIG. 36 is a sectional view of a planar transformer according to a fifth comparative example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Insulating layer, 11 ... 1st conductor layer, 11a ... 1st conductor pattern, 12 ... 2nd conductor layer, 12a ... 2nd conductor pattern, 13, 14 ... Terminal layer, 15-18 ... Through hole .

Claims (7)

[Claims] 1. A planar coil having an odd number of turns formed by a flat conductor, comprising: an insulating layer; and a first conductor pattern formed by spirally disposing the flat conductor. A first conductor layer having a second conductor pattern formed by spirally arranging plate-shaped conductors, and a second conductor pattern superimposed on the first conductor layer via the insulating layer. A conductor layer, wherein the first conductor pattern and the second conductor pattern each include a winding portion of N (N is an integer of 1 or more) +1 turns, and the first conductor pattern and the second conductor By connecting the innermost windings of the pattern in parallel,
A planar coil, wherein a winding of 2N + 1 turns is constituted by the first conductor pattern and the second conductor pattern. 2. The first conductor pattern and the second conductor pattern, wherein a width of an innermost winding portion is substantially half of a width of another winding portion. The planar coil as described. 3. In the first conductor pattern and the second conductor pattern, n turns (n is 1 or more,
The radius of the inner periphery of the winding portion of the (n + 1) th or less winding is r
_i (n), the radius of the outer circumference is r _o (n), the radius r _min of the inner circumference of the innermost winding portion, the radius of the outer circumference of the outermost winding portion, and the innermost winding portion Difference W from the radius of the inner circumference of
Given the _total and the distance D between the winding portions between adjacent turns, r _i (n) and r _o (n) are such that the value of A represented by equation (1) is minimized. The planar coil according to claim 1, wherein is defined. (Equation 1) (However, when K (1) = 0.5 and n ≧ 2, K (n) = 2,
r _i (1) = r _min , r _i (n + 1) −r _o (n) = D, r _o (N + 1) −r _i
(1) = W _total ) 4. A plurality of sets of insulating layers, a first conductive layer and a second conductive layer are stacked in a thickness direction, and windings of each set are connected in parallel. 4. The planar coil according to any one of 1 to 3. 5. A planar transformer having a primary winding and a secondary winding formed by conductors arranged in a plane, respectively, wherein at least one of the primary winding and the secondary winding has a flat plate shape. A first conductor layer having a first conductor pattern formed by spirally arranging conductors, and a second conductor pattern formed by spirally arranging flat conductors. A second conductor layer superposed on the first conductor layer via a layer, wherein the first conductor pattern and the second conductor pattern each have N (N is an integer of 1 or more) +1 turns A winding portion, wherein innermost winding portions of the first conductor pattern and the second conductor pattern are connected in parallel,
A planar transformer, wherein a winding of 2N + 1 turns is constituted by the first conductor pattern and the second conductor pattern. 6. The first conductor pattern and the second conductor pattern, wherein the width of the innermost winding portion is substantially half the width of the other winding portion. The described planar transformer. 7. In the first conductor pattern and the second conductor pattern, n turns (n is 1 or more,
The radius of the inner periphery of the winding portion of the (n + 1) th or less winding is r
_i (n), the radius of the outer circumference is r _o (n), the radius r _min of the inner circumference of the innermost winding portion, the radius of the outer circumference of the outermost winding portion, and the innermost winding portion Difference W from the radius of the inner circumference of
Given the _total and the distance D between the winding portions between adjacent turns, r _i (n) and r _o (n) are such that the value of A represented by equation (1) is minimized. The planar transformer according to claim 5, wherein is defined. (Equation 2) (However, when K (1) = 0.5 and n ≧ 2, K (n) = 2,
r _i (1) = r _min , r _i (n + 1) −r _o (n) = D, r _o (N + 1) −r _i
(1) = W _total )