JPH0777175B2 - Laminated transformer - Google Patents

Description

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 a structure of a conventional laminated transformer.
This figure is a plan view showing the protective substrate and insulating layers in a developed state before lamination, and each insulating layer 52A on which a conductor film is formed,
52B, 53A, 53B are sequentially laminated from the bottom, and protective substrates 54, 51 are further laminated on the upper and lower surfaces of the laminated body. Of these, a second-layer insulating substrate 52B from the bottom has a spiral-shaped wire ring electrode 55B of about 2 turns formed of a conductive film, and one end of the wire ring electrode 55B serves as an external extraction electrode 59, and the other. A through hole terminal 58B having a through hole structure is provided at the end. In addition, the first insulating layer laminated below this
On the surface of 52A, a linear wire ring electrode 55A is formed of a conductive film, one end of this wire ring electrode 55A serves as an external extraction electrode 57, and the other end faces the upper layer through-hole electrode 58b. The flat terminal 58a is formed. Then, by stacking the first insulating layers 52A and 52B, the upper and lower wire ring electrodes 55B and 55A are connected via the through-hole terminal 58b, and one of the outer lead electrodes 57 and 59 is connected. A coil element (primary coil) is formed. The surface of the insulating layer 53A, which is the third layer from the bottom, has a spiral shape formed of a conductor film.
The wheel electrode 56A of less than the turn is formed, and the wheel electrode 5A is formed.
One end of 6A serves as an external extraction electrode 60, and the other end has a flat terminal 61.
a is provided. On the other hand, a linear ring-shaped electrode 56B made of a conductor film is formed on the surface of the fourth insulating layer 53B laminated thereon, and one end of this ring-shaped electrode 56B becomes the external extraction electrode 62. A through hole terminal 61b having a through hole structure is provided at the other end so as to face the lower flat terminal 61a. Thus, the third and fourth insulating layers
By stacking 53A and 53B, the upper and lower coil electrodes 56B and 56A are connected via the through-hole terminal 61b, and the other coil element (secondary coil) is formed between the external extraction electrodes 60 and 62. . Then, the protective substrate 51 and each insulating layer 52A, 52B, 53A,
After sequentially stacking and firing 53B and the protective substrate 54, external electrodes are formed on the outer surface of the stacked body (the external lead-out electrodes 57 and 60 of both coil elements are connected by the external electrodes). A laminated transformer having an equivalent circuit similar to that is constructed.

FIG. 12 shows the structure of another conventional laminated transformer. The surface of each insulating layer 72A, 72B, 72C, 72D, 73A, 73B, 73C has less than one turn of the ring electrode 75A, 75B, 75C, 75D, 76A, 76B, 76C having a winding diameter substantially equal to that of the conductor film. Are provided respectively, and these insulating layers 72A, 72B, 72C, 72D, 73A,
73B and 73C are sequentially laminated from the bottom, and protective substrates 74 and 71 are laminated on the upper and lower sides of the laminated body to form a laminated transformer. Of these, one end of the ring-shaped electrode 75A formed on the surface of the first insulating layer 72A from below is the external extraction electrode 78,
A flat terminal 79a is provided at the other end. A through-hole terminal 79b is provided at one end of a coil electrode 75B formed on the surface of the second insulating layer 72B above it so as to face the lower flat terminal 79a, and a flat terminal 80a is provided at the other end. Has been. A through-hole terminal 80b is provided at one end of the coil electrode 75C of the third insulating layer 72C above it so as to face the lower flat terminal 80a.
A flat terminal 81a is provided at the other end. Further, a through-hole terminal 81b is provided at one end of the wire ring electrode 75D of the fourth insulating layer 72D on it so as to face the flat terminal 81a of the lower layer,
The other end serves as an external extraction electrode 82. When the insulating layers 72A, 72B, 72C and 72D are stacked, the through hole terminals 7
The ring electrodes 75A, 75B, 75C, and 75D are connected through 9b, 80b, and 81b, and one coil element is formed in the laminated body 77 as shown in FIG. Similarly, the fifth to seventh insulating layers are laminated from the bottom, and the flat terminal 84a at one end of the coil electrode 76A formed on the surface of the fifth insulating layer 73A and the sixth insulating layer 73B. Through-hole terminal 84b provided at one end of the loop electrode 76B on the surface of
And the flat terminal 85a provided at the other end of the coil electrode 76B.
And the through-hole terminal 85b provided at one end of the coil electrode 76C formed on the surface of the seventh insulating layer 73C are connected to each other, and the coil electrode 76A, 76B, 76C is used to connect the other between the external lead electrodes 83 and 86. Coil elements are formed.

[Problems to be Solved by the Invention] In the first conventional example shown in FIG. 10, insulating layers 52B and 53 are provided.
Since the spirally wound coil electrodes 55B and 56A having one or more turns are formed on the surface of A, the coil electrodes 55B and 56A come close to each other on the surface of the insulating layers 52B and 53A. 1
As shown in Fig. 1, a large stray capacitance C ₃ is generated between the adjacent wheel electrodes.

Further, in the second conventional example shown in FIG. 12, each coil is formed by the coil electrodes 75A-75D; 76A-76C on the insulating layers 72A-72D; Since the element is formed, the wire ring electrodes are vertically opposed to each other with the insulating layer (dielectric material) interposed therebetween, and the distance between the conductor films is as small as the thickness of one insulating layer. As shown in the figure, a large stray capacitance C ₄ is generated between the coil electrodes 75A to 75D and 76A to 76C facing each other vertically.

Thus, in any conventional laminated transformer,
A large stray capacitance is generated between the wire ring electrodes, and the first and second types of wire ring electrodes having less than one turn are formed by the high-frequency conductor film due to capacitive coupling between the wire ring electrodes caused by the stray capacitance. Stacking multiple insulating layers of each seed,
A spiral type first coil element is formed by connecting the spiral electrodes of each insulating layer of the first type, and a spiral coil shape is formed by connecting the spiral electrodes of each insulating layer of the second type. In a laminated transformer formed with a second coil element, an insulating layer of the first type and an insulating layer of the second type are alternately laminated, and conduction is established between the first and second insulating layers between the front and back of each insulating layer. The first coil element is formed by connecting the coil electrodes of the first type of insulating layer to each other through the connector provided in the second type of insulating layer to form the first coil element on the first type of insulating layer. The self-resonant frequency in the region characterized by forming the second coil element by connecting the wire ring electrodes of the second type of insulating layer through the provided connector, the predetermined inductance and impedance It was hard to get.

Therefore, the present invention has been made in view of the above-mentioned drawbacks of the conventional example, and an object thereof is to prevent the self-resonant frequency from being lowered due to the capacitive coupling between the wire ring electrodes, and to improve the high frequency characteristics of the laminated transformer. To be good.

[Means for Solving the Problems] This storage, the laminated transformer of the present invention is
A plurality of insulating layers of the first type and the second type, each having a winding electrode of less than one turn, are laminated, and the winding electrodes of the insulating layers of the first type are connected to each other to form a spiral shape. In the laminated transformer in which the coil element is formed, and the spiral-shaped second coil element is formed by connecting the wire ring electrodes of the second type insulation layers to each other, the insulation in which the input / output portion of the coil element is formed is formed. Except for the layers, the first type insulating layer and the second type insulating layer are alternately laminated,
The first and second types of insulating layers are provided with connectors that conduct electricity between the front and back of each insulating layer, and the ring electrodes of the first type of insulating layer are connected to each other via the connectors provided in the second type of insulating layer. To form the first coil element, and the second type coil element is formed by connecting the ring electrodes of the second type insulating layer to each other via the connector provided in the first type insulating layer. It is characterized by that.

[Operation] In the present invention, an insulating layer having a coil electrode forming the first coil element and an insulating layer having a coil electrode forming the second coil element are formed. 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 are different. Is twice the thickness of the insulating layer in the thickness direction of the insulating layer, and the coil electrodes are offset from each other, resulting in the distance between the coil electrodes being twice or more the thickness of the insulating layer. Therefore, the stray capacitance between the coil electrodes in each coil element is reduced to 1/2 or less.

For this reason, the capacitive coupling between the coil electrodes of each coil element is reduced, and the self-resonant frequency in the high frequency region is 2
The frequency at which self-resonance is doubled or more largely shifts to the high frequency side, and it becomes easy to obtain a desired inductance or impedance, and it is possible to manufacture a laminated transformer having excellent high frequency characteristics.

Further, since the wire ring electrodes forming the first coil element and the wire ring electrodes forming the second coil element are arranged alternately, the amount of magnetic flux interlinking each other increases. The coupling of both coil elements becomes dense, and a large coupling coefficient can be obtained.

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

1 to 5 show an embodiment of the present invention in which one end of a first coil element L ₅ (primary coil) and one end of a second coil element L ₆ (secondary coil) are connected to each other. It is a two-distribution transformer having an equivalent circuit as shown in FIG. 4 connected in common. This layer transformer 19 ,, the first three layers of ceramic insulating layers 2A constituting the coil element L _5, 2B, 2C and a second coil element L ₆
The three ceramic insulating layers 3A, 3B, 3C constituting the above are alternately laminated, and the protective substrate 4, 1 is further provided on both upper and lower surfaces of the laminated body 15.
Are laminated. On the surface of the first insulating layer 2A from the bottom, a loop electrode 5A that forms a part of the first coil element L ₅ is formed by printing a conductive paste with a constant width. One end of 5A serves as an external extraction electrode 7, and the other end is provided with a flat terminal 8a. On the surface of the second insulating layer 3A, a loop electrode 6A constituting a part of the second coil element L ₆ is wired by printing a conductive paste, and one end of the loop electrode 6A is external. It becomes the extraction electrode 11, and a flat terminal 12a is provided at the other end. Further, the second insulating layer is provided with a through hole connector 8b having a through hole structure corresponding to the lower flat terminal 8a.
Here, the through-hole connector is one in which a conductive paste is printed and baked around the upper surface of the through-hole that penetrates the insulating layer, the inner circumference of the through-hole, and the lower surface of the through-hole. The front and back surfaces of the insulating layer can be electrically connected at the child part. On the surface of the insulating layer 2B of the third layer, the first coil element Senwa electrode 5B constituting part of L ₅ and is wired, the lower through-hole connector 8b to one end of Senwa electrode 5B A through-hole terminal 8c with a through-hole structure is provided facing the
9a is provided. This through-hole terminal also has a structure similar to that of the through-hole connector, and is capable of conducting both the front and back surfaces of the insulating layer. In addition, the insulating layer
2B is provided with a through hole connector 12b facing the flat terminal 12a in the lower layer. On the surface of the fourth insulating layer 3B, a loop electrode 6B forming a part of the second coil element L ₆ is wired by a conductor film, and one end of the loop electrode 6B is provided with a lower layer. A through hole terminal 12c is provided facing the through hole connector 12b, and a flat terminal 13a is provided at the other end. Further, the insulating layer 3B is provided with a through hole connector 9b facing the lower flat terminal 9a. On the surface of the fifth insulating layer 2C, a wire ring electrode forming a part of the first coil element L ₅ is formed.
5C is provided, a through-hole terminal 9c is provided at one end of the ring electrode 5C so as to face the through-hole connector 9b in the lower layer, and the other end is the external lead electrode 10.
Further, a through hole connector 13b is provided so as to face the lower flat terminal 13a. The surface of the insulating layer 3C of the sixth layer, and Senwa electrode 6C is provided to constitute a second coil element L _6, to one end of Senwa electrode 6C and the lower through-hole connector 13b Through-hole terminals 13c are provided facing each other, and the other end serves as an external lead electrode 14. Moreover, the coil electrodes 5A, 5B, 5 forming the coil elements L ₅ , L ₆
The winding diameters of C and 6A, 6B, 6C are smaller on the lower layer side.

Then, the protective substrate 1 and the insulating layers 2A, 3A, 2B, 3B, 2C, 3
C and the protective substrate 4 are sequentially laminated from the bottom in the state of a green sheet, pressed against each other, and then fired. As a result, the protective substrates 1 and 4 and the insulating layers 2A to 2C and 3A to 3C form a laminated body 15 which is joined by sintering, and as shown in FIG. Embedded. Moreover, as shown in a partially enlarged view in FIG. 5, the through-hole connector 13b
And the ring-shaped electrodes 6B and 6C are connected via the through-hole terminal 13c, and the ring-shaped electrodes 6B and 6A are connected via the through-hole connector 12b and the through-hole terminal 12c, and the lower layer between the external extraction electrodes 11 and 14. The second spiral coil element L ₆ having a smaller winding diameter on the side is formed, and the through-hole connector 9b is similarly formed.
And the ring-shaped electrodes 5C and 5B are connected via the through-hole electrode 9a, the ring-shaped electrodes 5B and 5A are connected via the through-hole connector 8b and the through-hole terminal 8a, and the external extraction electrodes 7 and 10 are connected.
In between, a spiral first coil element L ₅ having a smaller winding diameter on the lower layer side is formed. After this, as shown in FIG.
The external electrodes 16, 17, 18 are formed by printing and baking a conductive paste on the exposed portions of the external extraction electrodes 7, 14 and 11, 10. The external extraction electrodes 7 and 14 are connected by the external electrode 16, and both coil elements L ₅ and L ₆ are connected so as to form an equivalent circuit as shown in FIG.

In the above description, one laminated transformer is manufactured as a single unit, but in the actual manufacturing process, a pattern of several tens to several hundreds of wire ring electrodes is formed on the mother sheet of each insulating layer. Then, these mother sheets are laminated to form a mother body of a laminated body, which is then cut into a laminated body of each element unit and fired, and external electrodes are formed on the outer surface of the laminated body.

As a result, as shown in FIG. 3 and FIG. ₅ , the insulating layers 2A, 2B, 2C for the first coil element L ₅ are located between the insulating layers 3A, 3B for the second coil element L ₆ . Since the two coil electrodes 5A, 5B, 5C forming the first coil element L ₅ are separated from each other in the thickness direction of the insulating layer, the second coil element L ₅ is also separated by the same distance. The coil electrodes 6A, 6B, 6C forming L ₆ are also separated from each other by twice the thickness in the thickness direction of the insulating layer, and the coil elements L ₅ and L ₆ are spiral-shaped and the coil electrodes are 5A
~ 5C, 6A ~ 6C are skewed, so each coil electrode 5
The distance between A to 5C and 6A to 6C becomes more than twice the thickness of the insulating layer, and therefore the stray capacitance C ₁ generated between the wire ring electrodes 5A, 5B and 5C and the wire ring electrodes 6A, 6B and 6C. The stray capacity C ₁ generated during this time becomes extremely small. That is, FIG. 12 and FIG.
Compared with the conventional example shown in the figure, the stray capacitance is 1/2 or less, and the self-resonant frequency is more than double that of the conventional example. Further, according to such a configuration, the first coil element L ₅ and the second coil element L ₆ are arranged so as to alternately engage with each other, so that the mutual coil elements L ₅ and L ₆ do not interfere with each other. The induction coefficient can be increased. Further, when used in a wide band transformer or a high frequency transformer such as a two-distribution transformer, a uniform distributed capacitance can be obtained by the first coil element and the second coil element.

6 to 9 show another example of the present invention, in which the external extraction electrodes 27, 31, 32, and 35 at both ends of the first and second coil elements L ₂₅ and L ₂₆ are separately provided. It is provided with external electrodes 37, 38, 39, 40 and is used as a pulse transformer or a common mode choke coil. The pattern of the ring 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 wire electrodes 25C, 26B of the fourth to seventh layers are formed. , 25D,
The pattern of 26C is the same as the ring electrodes 5B, 6B, 5C, 6C of the third to sixth layers of the first embodiment, but the ring electrodes 25A, 25B, 26A of the first to third layers are used. Pattern is different from that of the first embodiment. Thus, in this embodiment, the protective substrate 21, the insulating layers 22A, 22B, 23A, 22C, 23B, 22D, 23C and the protective substrate 24 are sequentially laminated from the bottom, and the laminated body 36 is integrated by firing. The laminated transformer 41 is configured by forming both coil elements of the conductive film on the through hole terminal 34c,
The coil electrodes 26C and 26B are connected via the through-hole connecting coil 34b and the flat terminal 34a, and the coil electrode 25 is connected via the through-hole terminal 33c, the through-hole connecting coil 33b and the flat terminal 33a.
The second coil element L ₂₆ is formed between the external extraction electrodes 35 and 32 by connecting B and 26A. On the other hand, through-hole terminal 30
c, the loop electrode 25D and 25C are connected through the through-hole connector 30b and the flat terminal 30a, and the loop electrode 25 is connected through the through-hole terminal 29c, the through-hole connecting coil 29b and the flat terminal 29a.
A first coil element L ₂₆ is formed between the external extraction electrodes 21 and 27 by connecting C and 25B and connecting the ring-shaped electrodes 25B and 25A through the through-hole terminal 28c. Also in this embodiment, both coil elements L ₂₅ and L ₂₆ are spiral-shaped, and the winding diameters of the lower coil electrodes 25A to 25D and 26A to 26C are smaller. Then, after stacking the stacked body, external extraction electrodes 37, 38, 39, 40 are provided on the outer surface of the stacked body 36 corresponding to the respective external extraction electrodes 27, 32, 31, 35.

Even in this conventional example, the first coil element L
₂₅ except the first-layer coil electrode 25A and the second-layer coil electrode 25B that form the input / output unit of ₂₅ , the coil electrodes 25B, 25C, 25D and the second coil electrodes 25B, 25C and 25D that form the first coil element L ₂₅ . Since the coil electrodes 26A, 26B and 26C forming the coil element L ₂₆ are obliquely shifted and alternately stacked, as shown in FIG.
Senwa electrode 25B constituting the _25, 25C, the distance between 25D and second Senwa electrodes 26A constituting the coil element L _26, 26B, the distance between 26C become less than twice the thickness of the insulating layer, the first In the same manner as in Example 1, the stray capacitance C ₂ between the wire ring electrodes becomes 1/2 or less of the conventional value, and the self-resonant frequency becomes twice or more the value of the conventional value, and the high frequency characteristics of the laminated transformer can be improved. . In addition, since capacitance also occurs between the first coil element and the second coil element, when used in a common mode choke coil whose main purpose is to eliminate common mode, it is possible to eliminate 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, the insulating layer provided with the coil electrode forming the first spiral coil element and the coil electrode forming the second coil element having the spiral coil were provided. Since the insulating layers are alternately laminated, the distance between the wire ring electrodes forming the same coil element becomes twice or more the thickness of the insulating layer, and the distance between the wire ring electrodes becomes large. The stray capacity generated during the process is reduced to less than half. For this reason, the self-resonant frequency in the high-frequency region is double or more than the conventional frequency, and the frequency at which self-resonance occurs moves to the high-frequency side. Therefore, it is possible to prevent the deterioration of the high frequency characteristics due to the decrease of the self-resonant frequency, and it is possible to obtain the laminated transformer having the excellent high frequency characteristics. Further, according to the present invention, since the wire ring electrodes forming the first coil element and the wire ring electrodes forming the second coil element are alternately laminated, the mutual induction coefficient of the laminated transformer is increased. be able to.

[Brief description of drawings]

FIG. 1 is a plan view showing each insulating layer before stacking according to one embodiment of the present invention, FIG. 2 is a perspective view of a stacked transformer formed by stacking each insulating layer of FIG. 1, and FIG. XX of FIG.
FIG. 4 is an equivalent circuit diagram of the above laminated transformer,
FIG. 5 is an enlarged sectional view showing a part of the above laminated transformer, FIG. 6 is a plan view showing each insulating layer before lamination of another example of the present invention, and FIG. 7 is each insulating shown in FIG. FIG. 8 is a perspective view of a laminated transformer formed by laminating layers, and FIG. 8 is YY of FIG.
A line sectional view, FIG. 9 is an equivalent circuit diagram of the same laminated transformer,
FIG. 10 is a plan view showing each insulating layer before stacking in the first conventional example, FIG. 11 is an explanatory view showing stray capacitance generated in the same stacked transformer, and FIG. 12 is a second conventional example. FIG. 13 is a plan view showing each insulating layer before stacking, and FIG. 13 is a cross-sectional view of a stacked transformer formed by stacking the above insulating layers. 2A to 2C, 3A to 3C ...... Insulating layer 5A to 5C, 6A to 6C ...... Wire ring electrode 8b, 9b, 12b, 13b ...... Through hole connector L ₅ , L ₆ ...... Coil element 22A to 22D, 23A 〜23C …… Insulating layer 25A〜25D, 26A〜26C …… Wheel electrode 29b, 30b, 33b, 34b …… Through hole connector L ₂₅ , L ₂₆ …… Coil element

Claims (1)

[Claims] 1. A plurality of insulating layers of a first type and a second type each having a winding electrode of less than one turn formed of a conductive film are laminated, and the winding electrodes of the insulating layers of the first type are connected to each other. A laminated transformer in which a spiral-shaped first coil element is connected to form a spiral-shaped second coil element by connecting coil electrodes of second-type insulating layers to each other. Except for the insulating layer in which the input / output section is formed, the first type insulating layer and the second type insulating layer are alternately laminated, and the first type and second type insulating layers are provided between the front and back of each insulating layer. An electrically conductive connector is provided, and the coil electrodes of the first type of insulating layer are connected to each other through the connector provided in the second type of insulating layer to form the first coil element, and the first type of insulation is provided. A product characterized in that the coil electrodes of the second type of insulating layer are connected to each other through a connector provided in the layer to form a second coil element. Layer transformer.