JPH03153011A - Laminated transformer - Google Patents

Abstract

PURPOSE:To prevent a drop in a self-resonance frequency due to capacitive coupling between coil electrodes by a method wherein insulating layers where the coil electrodes constituting a first coil element and a second coil element have been formed are laminated alternately, the coil electrodes corresponding to the individual coil elements are connected and the spiral-shaped coil element is formed. CONSTITUTION:In a laminated transformer, three layers each of ceramic insulating layers 2A to 2C and 3A to 3C constituting a first coil element and a second coil element L5, L6 are laminated alternately; protective substrates 4, 1 are laminated on the surface and the rear surface. In said insulating layers, coil electrodes 5A to 5C, 6A to 6C which constitute parts of the coil elements and whose winding diameter becomes smaller toward the lower-layer side are formed; the coil electrodes 6B and 6C are connected via a through-hole connecting piece 13b formed in the insulating layer 2C and a through-hole terminal 13c of the coil electrode 6C of the insulating layers 3C; the coil electrodes 6B and 6A are connected via a through-hole connecting piece 12b formed in the insulating layer 2B and a through-hole terminal 12c of the coil electrode 6B of the insulating layer 3B; the second spiral-shaped coil element L6 is constituted between external lead-out electrodes 11, 14 of the coil electrode 6A, 6C. In the same manner, the first coil element L5 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laminated transformer that can be used as various transformers, common mode choke coils, baluns, and the like.

[Background Art] FIG. 10 shows the structure of a conventional laminated transformer. This figure is an expanded plan view showing the protective substrate and insulating layer before lamination, and each insulating layer 5 on which a conductive film is formed.
2A, 52B, 53A, and 53B are laminated sequentially from the bottom, and protective substrates 54 and 51 are further laminated on the upper and lower door surfaces of the laminated body. Among these, on the insulating substrate 52B, which is the second layer from the bottom, a spiral wire electrode 55B with about two turns is formed of a conductive film, and one end of the wire wire electrode 55B becomes an external extraction electrode 59, and the other end is formed of a conductive film. A through-hole terminal 58B having a through-hole structure is provided at the end. Moreover, on the surface of the first insulating layer 52A laminated below,
A linear wire electrode 55A is formed of a conductor film, one end of this wire electrode 55A serves as an external lead electrode 57, and a child terminal 58a is formed at the other end to face the upper layer through-hole electrode 58b. ing. By stacking the first insulating layers 52A and 52B,
Upper and lower coil electrodes 55 are connected via through-hole terminals 58b.
B and 55A are connected, and one coil element (-secondary coil) is formed between the external extraction electrodes 57 and 59. Also,
On the surface of the third insulating layer 53A from the bottom, a coil electrode 56A having a spiral shape of less than two turns is formed by a conductor film, and one end of the coil electrode 56A is connected to the external extraction electrode 6.
0, and a child terminal 61a is provided at the other end.

On the other hand, on the surface of the fourth insulating layer 53B laminated thereon, a linear wire electrode 58B is formed of a conductor film, and one end of this wire wire electrode 56B becomes an external extraction electrode 62. At the other end, a through-hole terminal 61b having a through-hole structure is provided to face the lower-layer child terminal 81a. Therefore, the third and fourth insulating layers 53A
, 53B, the through-hole terminal 81
The upper and lower wire ring electrodes 56B and 58A are connected via b, and the other coil element (secondary coil) is formed between the external extraction electrodes 60 and 82. And the protective substrate 51 and each insulating layer 52A, 52B, 53A.

53B and the protective substrate 54 are sequentially laminated and fired, and then an external electrode is formed on the outer surface of the laminated body (the external lead electrodes 57 and 60 of both coil elements are connected by the external electrode). A laminated transformer with an equinodal circuit similar to is constructed.

FIG. 12 shows the structure of another conventional laminated transformer. Each insulating layer 72A, 72B, 72C, 72D, 7
On the surfaces of 3A, 73B, and 73C, coil electrodes 75A, 7 with less than one turn and having approximately equal winding diameters are formed by conductive films.
5B, 75C, 75D.

76A, 18B, 76C are provided respectively, and these insulating layers 72A, 72B, 72C, 72D, 73A
, 73B, and 73C are sequentially stacked from the bottom, and protective substrates 74 and 71 are stacked on top and bottom of the stack to form a multilayer transformer. Among these, the first insulating layer 72A from the bottom
One end of the coil electrode 75A formed on the surface becomes an external lead electrode 78, and the other end is provided with a child terminal 79a.

A wire ring shape formed on the surface of the second insulating layer 72B above it! A through-hole terminal 79b is provided at one end of 75B to face the child terminal 7θa in the lower layer, and a child terminal 8 is provided at the other end.
0a is provided. The third insulating layer 72C thereon
The wire type t! A through-hole terminal 80b is provided at one end of 75C to face the child terminal 80a in the lower layer, and a child terminal 81a is provided at the other end. Furthermore, the fourth
A through-hole terminal 81b is provided at one end of the coil electrode 75D of the insulating layer 72D to face the child terminal 81a of the lower layer, and the other end is an external lead-out electrode 82. And each insulation layer? 2A, 72B, 72C.

When 72D are stacked, each through-hole terminal 79b is formed.

Wire electrodes 75A, 75B are passed through 80b, 81b.

75C and 75D are connected to form one coil element in the stacked body 77 as shown in FIG.

Similarly, the fifth to seventh insulating layers are stacked from the bottom, and the fifth to seventh insulating layers are stacked.
A child terminal 84a at one end of the coil electrode 78A formed on the surface of the insulating layer 73A of the layer, and a through-hole terminal 84 provided at one end of the coil electrode 76B on the surface of the sixth layer insulating layer 73B.
b, and a child terminal 85a provided at the other end of the coil electrode 76B and a through-hole terminal 8 provided at one end of the coil electrode 76C formed on the surface of the seventh layer insulating layer '73C.
5b are connected, and the other coil element is formed between the external extraction electrodes 83 and 86 by the coil electrodes 78A, 76B, and 78C.

“Problems to be Solved by the Invention” In the first conventional example shown in FIG.
On the surfaces of B and 53A, spiral wire electrodes 55B and 5E with one turn or more are formed. Since A is formed,
On the surfaces of the insulating layers 52B and 53A, wire electrodes 55B,
58A, and as shown in FIG. 11, a large stray capacitance C8 is generated between adjacent wire electrodes.

Moreover, in the second conventional example shown in FIG.
Wire ring electrodes 75A to 75D on 3A to 73C; 78A
Since each coil element is formed by ~76C,
The wire electrodes are arranged vertically facing each other with an insulating layer (dielectric) in between, and the distance between the conductor films is as small as the thickness of the insulating layer. Opposed coil electrodes 75A to 75D: 76A to 76
A large stray capacitance C4 occurs between C and C.

In this way, no matter what type of conventional laminated transformer it is,
A large stray capacitance occurs between the coil electrodes, and due to the capacitive coupling between the coil electrodes that occurs through this stray capacitance, the coil electrodes of less than one turn are formed with a high frequency conductor film. Laminate multiple insulating layers for each species,
The coil electrodes of each of the first type insulating layers are connected to each other to form a spiral-shaped first coil element, and the coil electrodes of each of the second type of insulating layers are connected to each other to form a spiral shape. In the laminated transformer in which the second coil element is formed, the first type of insulation layer and the second type of insulation layer are alternately laminated, and conduction is established between the front and back of each insulation layer between the first type and the second type of insulation layer. The coil electrodes of the first type insulating layer are connected to each other through the connector provided on the second type insulating layer to form a first coil element. The self-resonant frequency in the region characterized by forming the second coil element by connecting the coil electrodes of the second type of insulating layer to each other via the connector provided in the second type of insulation layer decreases,
It has become difficult to obtain a predetermined inductance or impedance.

However, the present invention was made in view of the drawbacks of the conventional example of the inclined top, and its purpose is to prevent the self-resonant frequency from decreasing due to capacitive coupling between the coil electrodes, and improve the high frequency characteristics of the laminated transformer. The goal is to make things better.

[Means for Solving the Problems] The laminated transformer of the present invention has one
A plurality of insulating layers of the first type and the second type each having a coil electrode of less than a turn are laminated, and the coil electrodes of each of the first type insulating layers are connected to each other to form a spiral-shaped first layer. In a laminated transformer in which a coil element is formed, and a coil electrode of each second type insulating layer is connected to each other to form a spiral second coil element, the input/output part of the coil element is formed with an insulator. The first type of insulating layer and the second type of insulating layer are alternately laminated except for the layer,
Connectors that are electrically connected between the front and back sides of each insulating layer are provided on the first and second type insulating layers, and the coil electrodes of the first type insulating layer are connected to each other via the connectors provided on the second type insulating layer. were connected to form a first coil element, and wire electrodes of the second type of insulating layer were connected to each other via a connector provided on the first type of insulating layer to form a second coil element. It is characterized by

[Function] In the present invention, an insulating layer formed with a coil electrode forming the first coil element and an insulating layer forming a coil electrode forming the second coil element. Stacked alternately,
Moreover, since each coil element has a spiral shape and the winding diameter changes for each coil electrode, the distance between the coil electrodes in the first coil element and the distance between the coil electrodes in the second coil element is twice the thickness of the insulating layer in the thickness direction of the insulating layer, and the coil electrodes are diagonally shifted from each other, and as a result, the distance between the coil electrodes is more than twice the thickness of the insulating layer. Therefore, the stray capacitance between the coil electrodes inside each coil element becomes 172 or less.

Therefore, the capacitive coupling between the coil electrodes of each coil element is small (and the self-resonance frequency in the high frequency region is lower than that of the conventional 2).
The frequency at which self-resonance occurs is more than doubled, and the frequency at which self-resonance occurs largely shifts to the higher frequency side, making it easier to obtain desired inductance and impedance, and making it possible to manufacture a laminated transformer with good high frequency characteristics.

In addition, since the wire electrodes forming the first coil element and the wire electrodes forming the second coil element are arranged alternately, the amount of cross-linked magnetic flux between them increases. The coupling between both coil elements becomes tighter, and the coupling coefficient can be increased.

[Example] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

What is shown in FIGS. 1 to 5 is an embodiment of the present invention, in which one end of the first coil element La (-secondary coil) and the second coil element t, a (secondary coil) are connected. This is a two-way distribution transformer with both circuits connected in common, as shown in Figure 4. This laminated transformer 19 includes 1, a first coil element L6
The three ceramic insulating layers 2A, 2B, 2C constituting the second coil element L6 and the three ceramic insulating layers 3A, 3B, 3C constituting the second coil element L6 are alternately laminated to form a laminate 15.
A protective substrate 4.1 is further laminated on both the upper and lower surfaces of the substrate. The first coil element L is printed on the surface of the first insulating layer 2A from the bottom by printing a conductive paste with a constant width.
A coil electrode 5A constituting a part of the coil electrode 6 is formed, one end of the coil electrode 5A serves as an external lead electrode 7, and a child terminal 8a is provided at the other end. A coil electrode 6A forming a part of the second coil element L6 is wired on the surface of the second insulating layer 3A by printing a conductive paste, and one end of the coil electrode 6A is connected to an external drawer. It becomes an electrode 11, and a child terminal 12a is provided at the other end. moreover,
The second insulating layer is provided with through-hole connectors 8b having a through-hole structure in correspondence with the child terminals 8a on the lower layer. Here, a through-hole connector is one in which a conductive paste is printed and baked around the upper surface of a through-hole that penetrates an insulating layer, the inner periphery of the through-hole, and the lower surface of the through-hole. Both the front and back sides of the insulating layer can be electrically connected in the child part. Third
A coil electrode 5B constituting a part of the first coil element L6 is wired on the surface of the insulating layer 2B, and one end of the coil electrode 5B is wired to face the through-hole connector 8b in the lower layer. A through-hole terminal 8c having a through-hole structure is provided at one end, and a child terminal 9a is provided at the other end. This through-hole terminal also has a structure similar to that of the through-hole connector, and is capable of electrically conducting both the front and back surfaces of the insulating layer. Further, the insulating layer 2B is provided with a through-hole connector 12b facing the lower layer child terminal 12a. In addition, on the surface of the fourth insulating layer 3B, a coil electrode 6B constituting a part of the second coil element L6 is wired with a conductive film, and one end of the coil electrode 6B is connected to a through-hole of the lower layer. A through-hole terminal 12c is provided opposite the hole connector 12b, and a child terminal 13a is provided at the other end. Furthermore, through-hole connectors 9b are provided in the insulating layer 3B to face the child terminals 9a in the lower layer. A coil electrode 5C that constitutes a part of the first coil element Lll is provided on the surface of the fifth insulating layer 2C, and one end of the coil electrode 5C is connected to the lower layer through-hole connector 9b. Through-hole terminals 9C are provided facing each other, and the other end is an external extraction electrode 10.
Further, a through-hole connector 13b is provided facing the child terminal 13a in the lower layer.

Further, on the surface of the sixth insulating layer 3C, a coil electrode 6C constituting the second coil element e is provided, and one end of the coil electrode 6C is connected to the lower layer through-hole connector 13b. Through-hole terminals 13c are provided facing each other,
The other end is an external lead electrode 14. Moreover, the coil electrodes 5A and 5B forming each coil element L6゜L6
, 5C, 6A, 6B, and 6C, the lower the layer, the smaller the winding diameter.

Therefore, the protective substrate 1 and the insulating layers 2A, 3A, 2B
, 3B, 2C, SC, and the protective substrate 4 are sequentially laminated from the bottom in the form of green sheets, pressed together, and then fired. As a result, the protective substrate 1°4 and each insulating layer 2A to 20
．． 3A to 3C are sintered and bonded laminates 15,
As shown in FIG. 3, a conductor film is embedded between each layer in the laminate 15. Moreover, as shown in a partially enlarged view in FIG. The coil electrodes 6B and 6A are connected via the wire electrode 12c, and the external extraction electrode 11
A second spiral coil element L8 with a smaller winding diameter on the lower layer side is constructed between and 14, and similarly connected to the coil electrode 5C via the through-hole connector 9b and the through-hole electrode 9a.
and 5B are connected, and the wire electrodes 5B and 5A are connected via the through-hole connector 8b and the through-hole terminal 8a.
A spiral first coil element with a smaller winding diameter is formed on the lower layer side between the external lead electrodes 7 and 10. After this, as shown in FIG. External electrodes 16, 17, 18 are formed by printing and baking a conductive paste on the exposed parts of 11 and 11.10.External lead electrodes 7 and 14 are connected by external electrode 16, and Both coil elements L6 and L8 are connected to form an equivalent circuit as shown in FIG.

Although the above explanation assumes that one laminated transformer is manufactured as a single unit, in the actual manufacturing process, patterns of several tens to hundreds of coil electrodes are formed on the mother sheet of each insulating layer. After laminating these mother sheets to form a mother body of a laminate, this is cut into laminates for each element, fired, and further external electrodes are formed on the outer surface of the laminate.

As a result, as shown in FIGS. 3 and 5, the insulating layers 2A, 2B, 2C for the first coil element Lll are sandwiched between the insulating layers 3A, 3B for the second coil element L6. Therefore, the coil electrodes 5A, 5B, and 5C that constitute the first coil element L6 are separated from each other by twice the thickness in the thickness direction of the insulating layer, and similarly constitute the second coil element L6. The coil electrodes eA, 6B, and 6C are also separated from each other by twice the thickness in the thickness direction of the insulating layer, and each coil element La and Le has a spiral shape.
, 6A to 6C are diagonally shifted from each other, the distance between each coil electrode 5A to 5C, 8A to 6C becomes larger than twice the thickness of the insulating layer.
Stray capacitance C1 and coil electrodes eA, 6B generated between
, the stray capacitance generated between eC becomes very small. That is, even when compared to the conventional examples shown in FIGS. 12 and 13, the stray capacitance is less than 1/2, and the self-resonant frequency is also more than twice that of the conventional example. Moreover, according to such a structure, the first coil element L6 and the first coil element L6. are arranged so as to mesh with each other alternately, so that the mutual induction coefficient between both coil elements L, , 1 can be increased. Further, when used in a wideband transformer or a high frequency transformer such as a two-distribution transformer, uniform distributed capacitance can be obtained between the first coil element and the second coil element.

What is shown in FIGS. 6 to 9 is the other side of the present invention, in which external electrodes 37 are provided separately at external lead-out electrodes 27, 31, 32, and 35 at both ends of the first and second coil elements L251 and L28. .38, 39, and 40, and is used as a pulse transformer or common mode choke coil.

The pattern of the coil electrodes in this embodiment is almost the same as the pattern of the first embodiment, but the positions of the external extraction electrodes are different, so that the coil electrodes 25C and 26B of the fourth to seventh layers are , 25D, and 26C are the wire electrodes 5B, eB, 5C, and 8 of the third to sixth layers of the first embodiment.
Same as C, but first to third layer coil electrodes 25A,
25B.

The pattern of 28A is different from the first embodiment. Therefore, in this embodiment, the protective substrate 21, each insulating layer 22
A, 22B, 23A, 22C, 23B, 22D, 23C
The laminated transformer 41 is constructed by sequentially laminating the protective substrate 24 from the bottom and baking and forming both coil elements of the conductive film in the integrated laminated body 36.
The coil electrodes 26C and 26B are connected via the through-hole terminal 34c, the through-hole connector 34b and the flat terminal 34a, and the through-hole terminal 33C and the through-hole connector 33 are connected.
The coil electrodes 26B and 28A are connected through the flat terminals 33a and 33a, and a second coil element L2B is formed between the external lead electrodes 35 and 32.

On the other hand, through-hole terminal 30C1 through-hole connector 3
0b and the wire electrodes 25D and 25C via the flat terminal 30a.
and connect wire electrodes 25C and 2 via through-hole terminal 29c, through-hole connector 29b and flat terminal 29a.
5B, connect wire electrodes 25B and 25A via through-hole terminal 28c, and connect external lead electrodes 31 and 2.
The first coil element bQa is constructed between the two. Also,
Even in this example, both coil elements L26+TJ2
B has a spiral shape, and the lower wire ring electrodes 25A to 2
5D and 28A to 26C have smaller winding diameters.

After laminating the laminate, each external lead electrode 27°32
．． External lead electrodes 37, 38, 39, and 40 are provided on the outer surface of the laminate 36 in correspondence to 31.35.

However, even in this conventional example, the first coil element L
2a, except for the first layer coil electrode 25A and the second layer coil electrode 25B, which constitute the input/output section of
Coil electrodes 25B, 25C+-25D constituting the coil element and coil electrodes 2E3A, 2 constituting the second coil element Lu1l.
6B and 26C are stacked alternately with diagonal shifts, so as shown in FIG. Wiring electrode 28A that constitutes the wire 26
, 28B, and 26C is more than twice the thickness of the insulating layer, and as in the first embodiment, the stray capacitance C2 between the coil electrodes is 172 or less than the conventional one, and the self-resonant frequency is more than twice the conventional one. , and the high frequency characteristics of the multilayer transformer can be improved. In addition, since capacitance is generated between the first coil element and the second coil element, when used in a common mode choke coil whose main purpose is to remove common mode, it also removes normal mode noise at the same time. can be done.

In any of the above embodiments, the number of turns of the coil element can be increased by increasing the number of laminated insulating layers.

[Effects of the Invention] According to the present invention, an insulating layer provided with a coil electrode forming a first coil element having a spiral shape and a coil electrode forming a second coil element forming a spiral shape are provided. Since the insulating layers are alternately laminated, the distance between the coil electrodes that make up the same coil element is more than twice the thickness of the insulating layer, and the distance between the coil electrodes becomes large. The stray capacitance generated between the electrodes is reduced to 172 or less. Therefore, the self-resonant frequency in the high frequency region becomes more than twice that of the conventional one, and the frequency at which self-resonance occurs shifts to the high frequency side. Therefore, deterioration of high frequency characteristics due to a decrease in self-resonant frequency can be prevented, and a laminated transformer with good high frequency characteristics can be obtained.

Further, according to the present invention, since the coil electrodes constituting the first coil element and the coil electrodes constituting the second coil element are alternately laminated, the mutual induction coefficient of the laminated transformer is increased. be able to.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing each insulating layer before lamination according to an embodiment of the present invention, FIG. 2 is a perspective view of a laminated transformer formed by laminating the insulating layers shown in FIG. 1, and FIG. XX in Figure 2
Line sectional view, Figure 4 is an equivalent circuit diagram of the same laminated transformer as above,
FIG. 5 is an enlarged cross-sectional view of a part of the laminated transformer described above, FIG. 6 is a plan view showing each insulating layer before lamination on the other side of the present invention, and FIG. 7 is a cross-sectional view showing each insulating layer in FIG. A perspective view of a laminated transformer formed by laminating layers, FIG. 8 is taken along Y-Y in FIG.
Line sectional view, Figure 9 is an equivalent circuit diagram of the above laminated transformer,
Fig. 10 is a plan view showing each insulating layer before lamination in the first conventional example, Fig. 11 is an explanatory diagram showing the stray capacitance generated in the same laminated transformer, and Fig. 12 is a plan view of the second conventional example. FIG. 13 is a plan view showing each insulating layer before lamination, and a sectional view of a laminated transformer formed by laminating the above insulating layers. 2A to 2C, 3A to 3C...Insulating layers 5A to 5C, eA to 6C... Wire electrodes 8b, 9b, 1
2b, 13b...Through hole connector, 1. L6... Coil elements 22A to 22D, 23A to 23C... Insulating layer 25A to
25D, 2f3A to 26C... coil electrodes 29b, 30
b, 33b, 34b...Through hole connector

Claims (1)

[Claims] (1) A plurality of insulating layers of the first type and the second type each each having a coil electrode of less than one turn formed by a conductor film are laminated, and the coil electrodes of each of the first type insulating layers are connected to each other. In a laminated transformer, a first coil element is formed in a spiral shape, and a second coil element is formed in a spiral shape by connecting the coil electrodes of each of the second type insulating layers. The first type of insulation layer and the second type of insulation layer are alternately laminated except for the insulation layer forming the output part, and conduction is established between the front and back of each insulation layer between the first type and the second type of insulation layer. A connector is provided, and the coil electrodes of the first type of insulation layer are connected to each other via the connector provided on the second type of insulation layer to form a first coil element, and the first type of insulation layer is A laminated transformer characterized in that a second coil element is formed by connecting coil electrodes of a second type of insulating layer to each other via a provided connector.