JP2008028045A - Laminated balun transformer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated balun transformer where a balance characteristic can be improved, occurrence of parasitic inductance can be controlled, and durability of mounting can be improved. <P>SOLUTION: The laminated balun transformer is that of one-to-four type, and it is provided with a substrate 1 of a magnetic substance, a laminated body 2, a substrate 3 of a magnetic substance, and external electrodes 4-1 to 4-6. The laminated body 2 is constituted by covering first and second transformers 5 and 6 and a non-magnetic substance 7, which are arranged in parallel. A primary side coil 5-1 of the first transformer 5 and a second side coil 6-2 of the second transformer 6, and a secondary side coil 5-2 and a primary side coil 6-1 are rotationally symmetric about the center line L respectively. Extension of fourth and sixth lines M4 and M6 is stopped at this side of the center line L if viewed from a lamination direction. Internal electrodes 53a and 63a are connected to the wide external electrode 4-4 on this side of the center line L. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laminated balun transformer used as a balanced-unbalanced converter such as an IC of a mobile phone or an antenna of a television receiver, for example, an impedance 1 to 4 conversion laminated balun transformer.

The one-to-four balun transformer has a first transformer 100 and a second transformer 200 as shown in the equivalent circuit diagram of FIG. Then, by connecting the coils 101 and 102 constituting the first transformer 100 and the coils 201 and 202 constituting the second transformer 200 as shown in the figure, the impedance on the unbalanced terminal 300 side and the balance terminals 301 and 302 are connected. The ratio with the impedance on the side is 1: 4.
Conventionally, as a laminated balun transformer having this type of circuit structure, for example, there are technologies disclosed in Patent Document 1 and Patent Document 2.
These laminated balun transformers are configured by laminating coil conductor patterns for forming coils of the first and second transformers 100 and 200, magnetic sheets, and nonmagnetic sheets, and are reduced in size. It has the feature in being.

Japanese Patent Laid-Open No. 04-206905 Japanese Patent Laid-Open No. 06-120428

  However, in the above-described conventional laminated balun transformer, when used in a mobile phone IC or the like, a high-frequency signal is handled, so that a large number of parasitic inductances are generated in a transformer connecting line for connecting the transformers 100 and 200. These parasitic inductances are a major factor that deteriorates the balance characteristics (amplitude balance and phase balance) between the differential signals input and output from the balance terminals 301 and 302. However, since the conventional multilayer balun transformer described above does not take any effective measures against such parasitic inductance, it is impossible to prevent the deterioration of the balance characteristics.

  The present invention has been made to solve the above-described problems, and provides a multilayer balun transformer that can improve the balance characteristics, suppress the generation of parasitic inductance, and increase the durability of mounting. The purpose is to do.

In order to solve the above problems, the invention of claim 1 includes a first magnetic substrate, a laminate that is laminated on the first magnetic substrate and includes the first transformer and the second transformer, and the laminate. The first transformer and the second transformer each include a primary coil and a secondary coil facing each other, and the first and second transformers are arranged. The end of the first line formed by extending one end of the primary coil of the first transformer so that the direction is substantially parallel to the first magnetic substrate in the insulator constituting the laminate. The end of the 3rd line which makes both ends of the secondary side coil use the end part of the 2nd line which makes the part an unbalanced terminal and extends the other end of the primary side coil as the balance terminal And the end of the 4th line A sixth line is formed by connecting a fifth line formed by extending one end of the primary coil of the second transformer to the first line of the first transformer and extending the other end of the primary coil. The end of the line is used as a ground terminal, and the seventh line formed by extending one end of the secondary coil of the second transformer is connected to the third line of the first transformer, and the other end of the secondary coil is extended. By setting the end of the eighth line to be a balanced terminal, the ratio of the impedance on the unbalanced terminal side to the impedance on the balanced terminal side is set to 1: 4, and the secondary coil of the second transformer is set to , The first transformer primary with respect to a centerline that lies on a plane that traverses between the primary and secondary coils of the first and second transformers and that is located in the gap between the first and second transformers. 180 ° rotational symmetry with side coil In addition, the primary side coil of the second transformer is set to be 180 ° rotationally symmetrical with the secondary side coil of the first transformer with respect to the center line, so that it is equally distributed on both sides of the center line. The inductance value of the first line of the first transformer and the seventh line of the second transformer, the inductance value of the second line of the first transformer and the eighth line of the second transformer, and the third line of the first transformer A laminated balun transformer in which an inductance value with respect to the fifth line of the second transformer and an inductance value with respect to the fourth line of the first transformer and the sixth line of the second transformer are equal to each other. Are provided on one outer surface of the laminate so as to be arranged at equal intervals in order along the arrangement direction of the first and second transformers, and the fourth to sixth external electrodes are provided, Provided on the outer surface facing one outer surface of the laminate so as to face the first to third external electrodes, respectively, the unbalanced terminal that is the end of the first line is used as the first external electrode, and the second line The balance terminal that is the end is the fourth external electrode, the ground terminal that is the end of the third line is the third external electrode for ground, and the balance terminal that is the end of the eighth line is the sixth external electrode. The fourth line and the sixth line are respectively extended from the end of the secondary coil of the first transformer and the end of the primary coil of the second transformer toward the fifth external electrode for ground. The ground terminals, which are the ends of the fourth line and the ground terminals, which are the ends of the sixth line, are positioned in front of the center line as viewed from the stacking direction. Connected configuration.
With this configuration, the ratio of the impedance on the unbalanced terminal side to the impedance on the balanced terminal side in the first and second transformers is set to 1: 4, so that the unbalanced signal input to the unbalanced terminal side can be transmitted from the balanced terminal side. It can be efficiently output as a balance signal. Further, the secondary side coil of the second transformer is set to be 180 ° rotationally symmetrical with the primary side coil of the first transformer with respect to the center line, and the primary side coil of the second transformer is set with respect to the center line. The inductance value of the first line of the first transformer and the seventh line of the second transformer, which are set to be 180 ° rotationally symmetric with the secondary coil of the first transformer and are equally distributed on both sides of the center line, The inductance value of the second line of the first transformer and the eighth line of the second transformer, the inductance value of the third line of the first transformer and the fifth line of the second transformer, and the fourth line and the first line of the first transformer Since the inductance values of the second transformer and the sixth line are equal to each other, the inductance values on both sides of the center line can be balanced. As a result, it is possible to improve the balance characteristics (amplitude balance and phase balance) of the balance signal output from the pair of balance terminals, and also to suppress parasitic inductance that is likely to occur when handling a high-frequency signal. it can. Furthermore, the ends of the fourth line and the sixth line extending from the end of the secondary side coil of the first transformer and the end of the primary side coil of the second transformer to the fifth external electrode for ground are centered. The lengths of the fourth and sixth lines can be shortened because they are not extended to the line and are positioned in front of the center line. As a result, the inductance values and copper losses of the fourth and sixth lines can be reduced. The DC resistance value can be further reduced. In particular, by setting the fifth external electrode to be wide, not only can the lengths of the fourth and sixth lines be further shortened, but also the bonding area of the fifth external electrode is increased and the Connection is strong. Further, since the area of the fifth external electrode is increased, the connection impedance is reduced, and the characteristic deterioration can be reduced.

According to a second aspect of the present invention, in the stacked balun transformer according to the first aspect, the fifth external electrode is separated into two electrodes arranged on both sides of the center line, and one electrode is an end of the fourth line. A ground terminal is connected and a ground terminal which is an end of the sixth line is connected to the other electrode.
With this configuration, the fifth external electrode is separated into two electrodes, so that the connection strength by these two electrodes is greater than the connection strength by one electrode and the land, and as a result, the durability of the mounting is improved. It can be further increased.

According to a third aspect of the present invention, in the multilayer balun transformer according to the first or second aspect, the second balun transformer is a part in the middle of the third line extending to the third external electrode side. The part located in the vicinity of the external electrode and the part located in the middle of the seventh line and in the vicinity of the second external electrode or both of the parts are connected to the second external electrode. The configuration.
With such a configuration, the third line or the seventh line or a part in the middle of both are connected to the second external electrode for grounding, so that all of the first to sixth external electrodes are inside the laminate. It becomes the structure which is connected and connected with the circuit. As a result, it is possible to prevent the occurrence of parasitic capacitance and parasitic inductance caused by the presence of the external electrode that is not connected to the circuit inside the multilayer body.

As described above in detail, according to the multilayer balun transformer of the present invention, it is possible to improve the balance characteristic of the balance signal output from the balance terminal and to suppress the parasitic inductance. There is an excellent effect that the line length can be shortened to further reduce the inductance value, the copper loss, and the direct current resistance value of the fourth and sixth lines. By setting the fifth external electrode to be wide, the lengths of the fourth and sixth lines can be further shortened, and as a result, the inductance values, copper loss, and DC resistance of the fourth and sixth lines can be reduced. There is an effect that the value can be further reduced and the durability of the mounting can be improved and the characteristic deterioration can be reduced.
Moreover, according to the laminated balun transformer of the invention of claim 2, the durability of mounting can be further enhanced.
According to the multilayer balun transformer of the invention of claim 3, since all the external electrodes are connected to the circuit in the multilayer body to prevent the generation of parasitic capacitance and parasitic inductance, the balun of the entire multilayer balun transformer is prevented. Loss can be greatly reduced.

  The best mode of the present invention will be described below with reference to the drawings.

  FIG. 1 is an exploded perspective view of a multilayer balun transformer according to a first embodiment of the present invention, and FIG. 2 is an external view of the multilayer balun transformer.

  As shown in FIG. 2, in this embodiment, a laminated balun transformer includes a magnetic substrate 1 as a first magnetic substrate, a laminate 2 laminated on the magnetic substrate 1, and the laminate 2. It comprised with the magnetic body board | substrate 3 as a 2nd magnetic body board | substrate adhere | attached on, and the external electrodes 4-1 to 4-6.

  As shown in FIG. 1, the laminate 2 includes a first transformer 5, a second transformer 6 having substantially the same structure and the same direction as the first transformer 5, and the first and second transformers 5 and 6. And a non-magnetic material 7 (see FIG. 2) as an insulator completely covered from the outside.

The nonmagnetic material 7 is a dielectric material, for example, and is formed by laminating nonmagnetic material layers 71 to 75. The first and second transformers 5 and 6 are patterned on such non-magnetic layers 71 to 74.
Specifically, the first transformer 5 is composed of a primary coil 5-1 and a secondary coil 5-2 that face each other in the stacking direction. The primary coil 5-1 was formed with the conductor pattern 51 and the conductor pattern 52, and the secondary coil 5-2 was formed with the conductor pattern 53 and the conductor pattern 54.
On the other hand, the second transformer 6 is also composed of a primary coil 6-1 and a secondary coil 6-2 that face each other in the stacking direction. The primary coil 6-1 was formed with the conductor pattern 63 and the conductor pattern 64, and the secondary coil 6-2 was formed with the conductor pattern 61 and the conductor pattern 62.

Here, the structure of the first and second transformers 5 and 6 will be described in detail.
The conductor patterns 51 and 64 are pattern-formed on the nonmagnetic material layer 71 laminated on the magnetic material substrate 1 by a photolithography method or the like. Then, after the nonmagnetic material layer 72 is laminated on the conductor patterns 51 and 64, the conductor patterns 52 and 63 are patterned on the nonmagnetic material layer 72.
3 is a plan view of the conductor patterns 51 and 64, FIG. 4 is a plan view of the nonmagnetic layer 72, FIG. 5 is a plan view of the conductor patterns 52 and 63, and FIG. 3 is an exploded perspective view showing a connection structure between patterns 51 and 64 and conductor patterns 52 and 63. FIG.
As shown in FIG. 3, the conductor pattern 51 has an internal electrode 51a drawn from the inside. And the edge part 51b-51d of a pattern is distribute | arranged to the right side of this internal electrode 51a, and the edge part 51e-51h is distribute | arranged to the left side. Further, as shown in FIG. 5, the conductor pattern 52 has an internal electrode 52a drawn to the outside. Then, on the side opposite to the internal electrode 52a, the rightward end portions 52b to 52d and the leftward end portions 52e to 52h are alternately arranged.
Then, as shown in FIG. 6, the end portions 51 b to 51 d of the conductor pattern 51 and the end portions 52 b to 52 d of the conductor pattern 52 are connected through the through holes 72 b to 72 d of the nonmagnetic material layer 72. The portions 51e to 51h and the end portions 52e to 52h of the conductor pattern 52 are connected through the through holes 72e to 72h. Thereby, a spiral primary coil 5-1 having both ends of the internal electrodes 51a and 52a is formed.

  That is, as shown in FIG. 5, the primary side coil 5-1 has a long first shape formed by extending the end of the conductor pattern 52 that is one end of the primary side coil 5-1 from the extension start point P <b> 1. As shown in FIG. 3, there is a first line M1 and a short second line M2 formed by extending the end of the conductor pattern 51, which is the other end of the primary coil 5-1, from the extension start point P2. is doing. As will be described later, the internal electrodes 52a and 51a that are the ends of the first and second lines M1 and M2 are used as an unbalanced terminal and a balanced terminal.

  On the other hand, the conductor pattern 64 has an internal electrode 64a led out to the outer central portion (position corresponding to the internal electrode 52a) of the adjacent conductor pattern 51. Then, left-side ends 64b to 64d and right-side ends 64e to 64h are alternately arranged on the side opposite to the side from which the internal electrode 64a is drawn. Further, as shown in FIG. 5, the conductor pattern 63 has an internal electrode 63a located in front of a center line L described later. The pattern ends 63b to 63d are arranged on the left side of the lead line of the internal electrode 63a, and the ends 63e to 63h are arranged on the right side. As shown in FIG. 6, the end portions 64 b to 64 d of the conductor pattern 64 and the end portions 63 b to 63 d of the conductor pattern 63 are connected through through holes 72 b ′ to 72 d ′ of the nonmagnetic material layer 72. The end portions 64e to 64h of the conductor pattern 64 and the end portions 63e to 63h of the conductor pattern 63 are connected through through holes 72e 'to 72h'. As a result, a spiral primary coil 6-1 having both ends of the internal electrodes 64a and 63a is formed.

  That is, as shown in FIG. 3, the primary coil 6-1 has a long first shape formed by extending the end of the conductor pattern 64, which is one end of the primary coil 6-1, from the extension start point P5. As shown in FIG. 5, the short end of the conductor pattern 63, which is the other end of the primary coil 6-1, extends from the extension start point P6 to the front of the center line L, as shown in FIG. 6 lines M6. The fifth line M5 and the first line M1 are connected through the through hole 72j of the nonmagnetic layer 72, and the internal electrode 63a of the sixth line M6 is used as a ground terminal.

Further, as shown in FIG. 1, the conductor patterns 53 and 62 are formed on a nonmagnetic material layer 73 laminated on the conductor patterns 52 and 63. After the nonmagnetic layer 74 is laminated on the conductor patterns 53 and 62, the conductor patterns 54 and 61 are patterned on the nonmagnetic layer 74.
7 is a plan view of the conductor patterns 53 and 62, FIG. 8 is a plan view of the nonmagnetic material layer 74, FIG. 9 is a plan view of the conductor patterns 54 and 61, and FIG. It is a disassembled perspective view which shows the connection structure of the patterns 53 and 62 and the conductor patterns 54 and 61. FIG.
As shown in FIG. 7, the conductor pattern 53 has an internal electrode 53 a located in front of the center line L. The pattern ends 53b to 53d are arranged on the right side of the lead line of the internal electrode 53a, and the ends 53e to 53h are arranged on the left side. As shown in FIG. 9, the conductor pattern 54 has an internal electrode 54 a led out to the outer central portion (position corresponding to the internal electrode 62 a) of the adjacent conductor pattern 61. Then, right-side ends 54b to 54d and left-side ends 54e to 54h are alternately arranged on the side opposite to the side from which the internal electrode 54a is drawn.
As shown in FIG. 10, the end portions 53 b to 53 d of the conductor pattern 53 and the end portions 54 b to 54 d of the conductor pattern 54 are connected through the through holes 74 b to 74 d of the nonmagnetic material layer 74. The end portions 53e to 53h and the end portions 54e to 54h of the conductor pattern 54 are connected through through holes 74e to 74h. As a result, a spiral secondary coil 5-2 having both ends of the internal electrodes 53a and 54a is formed.

  That is, as shown in FIG. 9, the secondary coil 5-2 has a long first shape formed by extending the end of the conductor pattern 54, which is one end of the secondary coil 5-2, from the extension start point P3. As shown in FIG. 7, the third line M3 and the second end of the conductor pattern 53 that is the other end of the secondary coil 5-2 are extended from the extension start point P4 to the front of the center line L. 4 lines M4. As will be described later, internal electrodes 54a and 53a that are ends of the third and fourth lines M3 and M4 are used as ground terminals, respectively.

On the other hand, the conductor pattern 62 has an internal electrode 62a led out to the outside. Then, on the side opposite to the internal electrode 62a, left-facing ends 62b to 62d and right-facing ends 62e to 62h are alternately arranged. As shown in FIG. 9, the conductor pattern 61 has an internal electrode 61a drawn from the inside. The pattern ends 61b to 61d are arranged on the left side of the lead line of the internal electrode 61a, and the ends 61e to 61h are arranged on the right side. As shown in FIG. 10, the end portions 62b to 62d of the conductor pattern 62 and the end portions 61b to 61d of the conductor pattern 61 are connected through the through holes 74b 'to 74d' of the nonmagnetic layer 74, The end portions 62e to 62h of 62 are connected to the end portions 61e to 61h of the conductor pattern 61 through through holes 74e 'to 74h'. As a result, a spiral secondary coil 6-2 having the internal electrodes 62a and 61a at both ends is formed.
The lead wires of the internal electrodes 54 a and 62 a are connected through the through hole 74 j of the nonmagnetic material layer 72.
As shown in FIG. 1, the nonmagnetic layer 75 is laminated on the conductor patterns 54 and 61, and the magnetic substrate 3 is bonded onto the nonmagnetic layer 75.

  In other words, as shown in FIG. 7, the secondary coil 6-2 is a long first coil formed by extending the end of the conductor pattern 62, which is one end of the secondary coil 6-2, from the extension start point P7. 7 and a short eighth line M8 formed by extending the end of the conductor pattern 61 which is the other end of the secondary coil 6-2 from the extension start point P8 as shown in FIG. is doing. The seventh line M7 and the third line M3 are connected through the through hole 74j of the nonmagnetic layer 74, and the internal electrode 61a of the eighth line M8 is used as a balance terminal, as will be described later.

  As shown in FIG. 1, external electrodes 4-1 to 4-6 are formed on the outside of the chip body having the above structure.

That is, as shown in FIGS. 1 and 2, the external electrodes 4-1, 4-6, 4-5, which are first to third external electrodes, are arranged in the direction in which the first and second transformers 5, 6 are arranged. It is provided on one outer surface of the laminate 2 so as to be arranged at regular intervals along the order (from the right side to the left side). Then, the external electrodes 4-2, 4-4, 4-3, which are the fourth to sixth external electrodes, are arranged on the laminate 2 so as to face the external electrodes 4-1, 4-6, 4-5, respectively. Provided on the other outer surface.
As shown in FIGS. 3 to 10, the internal electrode 52a (unbalanced terminal) of the first line M1 and the internal electrode 64a of the fifth line M5 are connected to the external electrode 4-1, and the second line M2 is connected. The internal electrode 51a (balance terminal) is connected to the external electrode 4-2. The internal electrode 54a (ground terminal) of the third line M3 and the internal electrode 62a of the seventh line M7 are connected to the ground external electrode 4-5, and the internal electrode 53a (ground terminal) of the fourth line M4. And the internal electrode 63a of the sixth line M6 are connected to the ground external electrode 4-4. Furthermore, the internal electrode 61a (balance terminal) of the eighth line M8 is connected to the external electrode 4-3.

FIG. 11 is a schematic diagram showing the electrical structure of the first and second transformers 5 and 6.
By connecting the conductor patterns as described above or connecting the external electrodes 4-1 to 4-6 and the internal electrodes, the electrical structure becomes a circuit structure as shown in FIG.
Such a circuit structure is the same as the equivalent circuit of the one-to-four balun transformer shown in FIG. As a result, in this multilayer balun transformer, the ratio of the impedance on the external electrode 4-1 side which is an unbalanced terminal to the impedance on the external electrode 4-2 and 4-3 side which is a balanced terminal is set to a ratio of 1: 4. Has a function to convert.

By the way, in the laminated balun transformer of this embodiment, as shown in FIG. 1, the first transformer 5 and the second transformer 6 are connected to the non-magnetic material 7 so that the arrangement direction thereof is substantially parallel to the magnetic substrate 1. It has a parallel structure. However, in this embodiment, the secondary coil 6-2 of the second transformer 6 is further set to have a 180 ° rotationally symmetric shape with respect to the primary coil 5-1 of the first transformer 5 with respect to the center line L. At the same time, the primary coil 6-1 of the second transformer 6 is set to have a 180 ° rotationally symmetric shape with respect to the secondary coil 5-2 of the first transformer 5 with respect to the center line L.
This will be specifically described below.
FIG. 12 is an exploded perspective view showing a 180 ° rotationally symmetric state between the secondary coil 6-2 of the second transformer 6 and the primary coil 5-1 of the first transformer 5. FIG. FIG. 4 is an exploded perspective view showing a 180 ° rotationally symmetric state between the primary side coil 6-1 of the transformer 6 and the secondary side coil 5-2 of the first transformer 5.
As shown in FIG. 1, the center line L crosses between the primary side coils 5-1 and 6-1 and the secondary side coils 5-2 and 6-2 of the first and second transformers 5 and 6. It is on a plane. Specifically, the center line L is located so as to penetrate the nonmagnetic layer 73 along the layer. Further, the center line L is located in the gap G between the first and second transformers 5 and 6. Therefore, the center line L penetrates the nonmagnetic layer 73 along the layers in the state facing the opposed external electrodes 4-1 to 4-6, and the width direction (left-right direction in FIG. 1). As viewed from the center of the gap G.
Then, the primary side coil 5-1 of the first transformer 5 and the secondary side coil 6-2 of the second transformer 6 are 180 ° rotationally symmetric with respect to the center line L as shown by an arrow A in FIG. It is set to be. Further, the secondary coil 5-2 of the first transformer 5 and the primary coil 6-1 of the second transformer 6 are in a state of being 180 ° rotationally symmetric with respect to the center line L as shown by an arrow B in FIG. It is set to be.

FIG. 14 is a plan view showing a state where the first line M1 to the eighth line M8 of the first and second transformers 5 and 6 are equally distributed on both sides of the center line L. FIG.
As described above, the primary side and secondary side coils 6-1 and 6-2 of the second transformer 6 are connected to the secondary side and primary side coils 5-2 and 5 of the first transformer 5 with respect to the center line L. -1 and 180 ° rotationally symmetric shape. Accordingly, as shown in FIGS. 14 and 1, when the stacked balun transformer is viewed from above, the first line M1 and the seventh line M7, the second line M2 and the eighth line M8, the third line M3 and the fifth line The line M5, the fourth line M4, and the sixth line M6 are equally distributed on both sides of the center line L in a line-symmetric state.
Therefore, the inductance values of the first line M1 and the seventh line M7 equally distributed on both sides of the center line L, the inductance values of the second line M2 and the eighth line M8, the third line M3 and the fifth line M5. And the inductance values of the fourth line M4 and the sixth line M6 are equal to each other.
Specifically, as shown in FIG. 5 (FIG. 7), the inductance value from the extension start point P1 (P7) of the first line M1 (seventh line M7) to the bending point P1 ′ (P7 ′) is expressed as L3. If the inductance value after the bending point P1 ′ (P7 ′) is L1, the inductance value of the first line M1 (seventh line M7) is L1 + L3. Further, as shown in FIG. 3 (FIG. 9), the inductance value of the second line M2 (eighth line M8) can be set to L4. When the inductance value from the extension start point P3 (P5) of the third line M3 (fifth line M5) to the midpoint P3 ′ (P5 ′) is L2, the inductance value after the midpoint P3 ′ (P5 ′) Becomes L1. For this reason, the inductance value of the 3rd line M3 (5th line M5) is L1 + L2. Further, as shown in FIG. 7 (FIG. 5), the inductance value of the fourth line M4 (sixth line M6) can be set to L5.

FIG. 15 is a plan view showing the lengths of the fourth line M4 and the sixth line M6.
As shown in FIGS. 15 and 14, in this embodiment, the fourth line M4 extends from the extension start point P4, which is the end of the secondary coil 5-2 of the first transformer 5, toward the external electrode 4-4. The sixth line M6 extends from the extension start point P6, which is the end of the primary coil 6-1 of the second transformer 6, toward the external electrode 4-4, but extends to the center line L. I have not let it. That is, by connecting the internal electrode 53a of the fourth line M4 and the internal electrode 63a of the sixth line M6 in front of the center line L, respectively, by connecting to the wide external electrode 4-4 for ground, The lengths of the fourth line M4 and the sixth line M6 were made as short as possible.

Next, operations and effects of the laminated balun transformer of this embodiment will be described.
In FIG. 2, the external electrode 4-1 that is an unbalanced terminal is connected to a line with an impedance of 50Ω, for example, and the external electrodes 4-2 and 4-3 that are balance terminals are connected to a balance line with an impedance of 200Ω, for example. The external electrodes 4-4 and 4-5, which are ground terminals, are grounded. As a result, the unbalanced-balanced line having an impedance ratio of 1: 4 can be effectively connected by the laminated balun transformer. As a result, when an unbalance signal is input from the external electrode 4-1, a pair of balance signals (differential signals) whose phases are shifted by 180 ° are output from the external electrodes 4-4 and 4-5. It becomes.

By the way, in a laminated balun transformer, when a high frequency signal is handled, a large number of parasitic inductances are generated in the connection line between the transformers, and the balance characteristic (amplitude) between the balance signals input and output from the external electrodes 4-2 and 4-3. (Balance and phase balance) may be adversely affected.
FIG. 16 is a circuit diagram showing the parasitic inductance generated in the balun transformer.
As shown in FIGS. 3 to 9, the inductance values of the first and seventh lines M1, M7 are L1 + L3, the inductance values of the second and eighth lines M2, M8 are L4, and the third and fifth lines M3, M5. Since the inductance value of the fourth and sixth lines M4 and M6 is L5, the laminated balun transformer of this embodiment generates parasitic inductances L1 to L5 as shown in FIG. It becomes.
However, in the laminated balun transformer of this embodiment, as described above, the first, seventh lines M1, M7, the second, eighth lines M2, M8, third, equally distributed on both sides of the center line L. Since the inductance values of the fifth line M3, M5 and the fourth and sixth lines M4, M6 are set to be equal to each other, the parasitic inductance on both sides of the center line L is balanced. That is, as shown in FIG. 16, since the parasitic inductances L1 to L5 are equally distributed symmetrically on both sides of the center line L ′, as shown in FIG. 16, the amplitudes of signals flowing on both sides of the center line L ′ Balance the phase. As a result, the balance characteristics (amplitude balance and phase balance) of the balance signal output from the external electrodes 4-2 and 4-3 which are balance terminals are improved.
Further, in the laminated balun transformer of this embodiment, as shown in FIGS. 3 to 9, the lengths for generating the parasitic inductances L2, L3, and L4 are very short. Therefore, these parasitic inductances L2, L3, and L4 are generated. Can be reduced to almost zero.
Further, as shown in FIG. 15, the inductance L5 is an inductance of a line that does not reach the center line L and is stopped in front, and the inductance value is very small.
The remaining parasitic inductance L1 is the inductance of the line drawn far away, and the inductance value is not small. However, as shown in FIG. 16, since the parasitic inductance L1 is equally distributed symmetrically on both sides of the center line L ′, the parasitic inductance L1 has the amplitude balance and phase balance of the input / output balance signal. The adverse effect on the characteristics is small.

As described above, according to the multilayer balun transformer of this embodiment, not only the balance characteristics of a pair of balance signals input / output from the external electrodes 4-2 and 4-3, respectively, but also the parasitic inductance is improved. Occurrence can be reduced.
In particular, as shown in FIG. 15, by connecting the internal electrodes 53a and 63a of the fourth and sixth lines M4 and M6 to the external electrode 4-4 before the center line L, respectively, the fourth and sixth lines Since the lengths of M4 and M6 are made as short as possible, the inductance L5, the copper loss and the direct current resistance value are reduced, and the insertion loss can be reduced.
The inventors conducted a simulation to confirm this assumption.
FIG. 17 is a plan view showing a state in which the fourth line M4 and the sixth line M6 extend to the center line L. FIG.
In the simulation, the laminated balun transformer of this embodiment shown in FIG. 15 and the laminated balun transformer in which the fourth and sixth lines M4 and M6 are located on the center line L as shown in FIG. The insertion loss (dB) of each laminated balun transformer was calculated for high frequencies of 50 MHz, 300 MHz, and 870 MHz.
Then, in the multilayer balun transformer having the fourth and sixth lines M4 and M6 having the length shown in FIG. 17, for each high frequency of 50 MHz, 300 MHz, and 870 MHz, −1.384 dB, −0.726 dB, −1. The insertion loss was 0.079 dB. On the other hand, in the laminated balun transformer of this embodiment having the fourth and sixth lines M4 and M6 having the length shown in FIG. 15, -1.403 dB, -0.720 dB,- It was confirmed that the insertion loss was 0985 dB, and the insertion loss was smaller as the frequency was higher than the multilayer balun transformer of FIG.

Further, since the external electrode 4-4 is set to be wide, the bonding area between the external electrode 4-4 and a land (not shown) is widened, and the connection strength at the time of mounting is increased. As a result, the durability of mounting the multilayer balun transformer is improved. Furthermore, as the area of the external electrode 4-4 is increased, the connection impedance with the land is reduced, and the characteristic deterioration can be reduced.
In this embodiment, the nonmagnetic material 7 as an insulator is applied. However, the present invention is not limited to this, and it is needless to say that a magnetic material can be applied as an insulator constituting the laminate 2.

Next explained is the second embodiment of the invention.
FIG. 18 is a plan view showing the main part of the multilayer balun transformer according to the second embodiment of the present invention.
In the multilayer balun transformer of this embodiment, the external electrode 4-4 is separated into two electrodes 41 and 42 arranged on both sides of the center line L as shown in FIG. Then, the electrode 41 that is one electrode is connected to the internal electrode 53a that is the end portion of the fourth line M4, and the internal electrode 63a that is the end portion of the sixth line M6 is connected to the electrode 42 that is the other electrode. Connected.

With this configuration, when the electrodes 41 and 42 are soldered to a land (not shown), the connection strength of the two electrodes 41 and 42 to the land is one external electrode 4- applied in the first embodiment. It becomes larger than the connection strength to 4 lands.
That is, by separating the two electrodes 41 and 42, the durability of the mounting can be further improved.
Since other configurations, operations, and effects are the same as those in the first embodiment, description thereof is omitted.

Next explained is the third embodiment of the invention.
FIG. 19 is an exploded perspective view of the multilayer balun transformer according to the third embodiment of the present invention, and FIG. 20 is an exploded view showing a connection structure between the third and seventh lines M3 and M7 and the external electrode 4-6. 21 is a perspective view, and FIG. 21 is a plan view showing a connection state between the first and eighth lines of the first and second transformers equally distributed on both sides of the center line and the external electrodes 4-1 to 4-6. It is.
As shown in FIGS. 19 and 20, in this embodiment, internal electrodes 54A and 62A connected to the external electrode 4-6 are provided in the middle of the third line M3 and the seventh line M7 of the laminated balun transformer. This is different from the first embodiment.

That is, in the configuration of the first embodiment, since the external electrode 4-6 is not electrically connected to the first and second transformers 5 and 6 that are internal circuits of the multilayer body 2, large parasitic inductance and parasitic capacitance are required. May occur between the external electrode 4-6 itself or between the external electrode 4-6 and the internal circuit. For this reason, when this laminated balun transformer is inserted on the line, a large insertion loss may occur.
Therefore, in this embodiment, as shown in FIGS. 19 and 20, internal electrodes 54A and 62A for connection to the external electrode 4-6 are provided on the third and seventh lines M3 and M7.

  That is, the internal electrodes 54A and 62A are provided to project in the middle of the third line M3 and the seventh line M7 connected to the ground external electrode 4-5. These internal electrodes 54A and 62A are provided in the middle of the third and seventh lines M3 and M7 so as to project at a position closest to the external electrode 4-6. The external electrode 4-6 is used as a ground electrode in the same manner as the external electrode 4-5.

  With this configuration, as shown in FIG. 20, the third and seventh lines M3 and M7 are connected to the external electrode 4-6 through the internal electrodes 54A and 62A. Parasitic inductance and capacitance generated between the electrode 4-6 and the internal circuit can be reduced. Furthermore, as shown in FIG. 21, the first line M1 and the seventh line M7, the second line M2 and the eighth line M8, the third line M3 and the fifth line M5, the fourth line M4 and the sixth line M6 In addition, since the inner electrodes 54A and 62A are positioned on the center line L while being equally distributed on both sides of the center line L, the electric circuit structure is balanced. From this point, it is considered that the multilayer balun transformer of this embodiment can largely suppress the insertion loss as compared with the first embodiment.

The inventors conducted a simulation to confirm this assumption.
In the simulation, the multilayer balun transformers of the first and third embodiments were respectively mounted on the lines, and the insertion loss (dB) of each multilayer balun transformer with respect to the high frequencies of 50 MHz, 100 MHz, and 870 MHz was calculated.
Then, in the laminated balun transformer of the first example, the insertion loss was -1.015 dB, -0.899 dB, and -1.124 dB with respect to the high frequencies of 50 MHz, 100 MHz, and 870 MHz. On the other hand, in the multilayer balun transformer of this example, it is confirmed that the insertion loss is −0.953 dB, −0.848 dB, −1.071 dB with respect to the high frequency, and the insertion loss is extremely small. It was.

In this embodiment, the internal electrodes 54A and 62A project from both the third line M3 and the seventh line M7, and both the third and seventh lines M3 and M7 are connected to the external electrode 4-6. It was set as the structure made to do. However, the internal electrode 54A or the internal electrode 62A protrudes from one of the third line M3 or the seventh line M7, and only one of the third or seventh line M3, M7 is connected to the external electrode 4-6. The laminated balun transformer also has substantially the same operations and effects as this embodiment.
Other configurations, operations, and effects are the same as those in the first and second embodiments, and thus description thereof is omitted.

1 is an exploded perspective view of a multilayer balun transformer according to a first embodiment of the present invention. It is an external view of a laminated balun transformer. It is a top view of the lowermost conductor pattern. It is a top view of a nonmagnetic material layer. It is a top view of the conductor pattern of the 2nd layer from the bottom. It is a disassembled perspective view which shows the connection structure of the lowermost conductor pattern and the 2nd conductor pattern. It is a top view of the conductor pattern of the 3rd layer from the bottom. It is a top view of a nonmagnetic material layer. It is a top view of the uppermost conductor pattern. It is a disassembled perspective view which shows the connection structure of the conductor pattern of the 3rd layer, and the uppermost conductor pattern. It is a schematic diagram which shows the electrical structure of a 1st and 2nd transformer. It is a disassembled perspective view which shows the 180 degree rotational symmetry state of the secondary side coil of a 2nd transformer, and the primary side coil of a 1st transformer. It is a disassembled perspective view which shows the 180 degree rotational symmetry state of the primary side coil of a 2nd transformer, and the secondary side coil of a 1st transformer. It is a top view showing the state where the 1st line-the 8th line of the 1st and 2nd transformer were equally distributed to the both sides of the center line. It is a top view which shows the length of a 4th line and a 6th line. It is a circuit diagram which shows the parasitic inductance which arises in a balun transformer. It is a top view which shows the state which extended the 4th line and the 6th line to the centerline. It is a top view which shows the principal part of the laminated | stacked balun transformer which concerns on 2nd Example of this invention. It is a disassembled perspective view of the laminated balun transformer which concerns on 3rd Example of this invention. It is a disassembled perspective view which shows the connection structure of the 3rd and 7th line and an external electrode. It is a top view which shows the connection state of the 1st line-8th line of the 1st and 2nd transformer equally distributed on the both sides of the centerline, and an external electrode. It is an equivalent circuit diagram of a 1 to 4 type balun transformer.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Magnetic material substrate, 2 ... Laminated body, 3 ... Magnetic material substrate, 4-1 to 4-6 ... External electrode, 5 ... 1st transformer, 5-1, 6-1 ... Primary side coil, 6 ... 1st 2 transformers, 5-2, 6-2 ... secondary coil, 7 ... non-magnetic material, 41, 42 ... electrodes, 51-54, 61-64 ... conductor patterns, 51a-54a, 61a-64a, 54A, 62A ... internal electrodes, 51b to 51h, 52b to 52h, 53b to 53h, 54b to 54h, 61b to 61h, 62b to 62h, 63b to 63h, 64b to 64h ... end, 72b to 72h, 72j, 72b 'to 72h' , 74b to 74h, 74j, 74b ′ to 74h ′, through holes, 71 to 75, nonmagnetic layers, L, center lines, L1 to L5, parasitic inductances, M1 to M8, first to eighth lines.

Claims (3)

A first magnetic substrate, a laminate that is laminated on the first magnetic substrate and encloses the first transformer and the second transformer, and a second magnetic substrate provided on the laminate,
The first transformer and the second transformer are respectively composed of a primary coil and a secondary coil facing each other, and the arrangement direction of the first and second transformers is substantially parallel to the first magnetic substrate. As shown in FIG.
The end of the first line that extends from one end of the primary coil of the first transformer serves as an unbalanced terminal, and the end of the second line that extends from the other end of the primary coil. The end of the third line and the end of the fourth line, each of which is a balance terminal, and both ends of the secondary coil are respectively ground terminals, and one end of the primary coil of the second transformer. The fifth line formed by extending the first coil is connected to the first line of the first transformer, and the end of the sixth line formed by extending the other end of the primary coil is used as a ground terminal. The end of the eighth line formed by connecting the seventh line formed by extending one end of the secondary coil to the third line of the first transformer and extending the other end of the secondary coil By using a balanced terminal Set the ratio between the impedance of the unbalanced terminal side of the impedance and the balanced terminal side to 1: 4,
The secondary side coil of the second transformer is on a plane crossing between the primary side coil and the secondary side coil of the first and second transformers and in the gap between the first and second transformers. The center line is set to be 180 ° rotationally symmetric with the primary coil of the first transformer, and the primary coil of the second transformer is set to the secondary of the first transformer with respect to the center line. By setting the side coil and 180 ° rotationally symmetrical shape,
Inductance values of the first line of the first transformer and the seventh line of the second transformer equally distributed on both sides of the center line, the second line of the first transformer and the eighth line of the second transformer, respectively. Inductance value between the third line of the first transformer and the fifth line of the second transformer, and the inductance value of the fourth line of the first transformer and the sixth line of the second transformer. , Each is an equal laminated balun transformer,
The first to third external electrodes are provided on one outer surface of the stacked body so as to be arranged at equal intervals in order along the arrangement direction of the first and second transformers, and the fourth to sixth external electrodes are provided. And provided on the outer surface facing one outer surface of the laminate so as to face the first to third external electrodes, respectively.
The unbalanced terminal that is the end of the first line is the first external electrode, the balance terminal that is the end of the second line is the fourth external electrode, and the end of the third line A ground terminal is connected to the third external electrode for ground, and a balance terminal which is an end of the eighth line is connected to the sixth external electrode,
The fourth line and the sixth line are respectively extended from the end of the secondary coil of the first transformer and the end of the primary coil of the second transformer toward the fifth external electrode for ground, The ground terminal, which is the end of the fourth line, and the ground terminal, which is the end of the sixth line, are connected to the fifth external electrode in a state where they are positioned in front of the center line as viewed from the stacking direction. did,
A laminated balun transformer characterized by this. In the laminated balun transformer according to claim 1,
The fifth external electrode is separated into two electrodes arranged on both sides of the center line, a ground terminal which is an end of the fourth line is connected to one electrode, and the sixth line is connected to the other electrode. Connect the ground terminal which is the end,
A laminated balun transformer characterized by this. In the laminated balun transformer according to claim 1 or 2,
A part in the middle of the third line extending to the third external electrode side, a part located in the vicinity of the second external electrode for ground and a part in the middle of the seventh line, the second line Any one or both of the parts located in the vicinity of the external electrode were connected to the second external electrode,
A laminated balun transformer characterized by this.

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