JP2007214789A - Composite coil and noise filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite coil and a noise filter capable of obtaining inductance values required for both a common mode signal and a normal mode signal. <P>SOLUTION: The composite coil has a core 10 and first to fourth windings 11 to 14 wound on the core 10. The core 10 is formed in a squarish eight form as a whole, and has an intermediate leg 20 and first to fourth sides 21 to 24 approximately orthogonal to the intermediate leg 20. The inductance values required to both the common mode signal and the normal mode signal are obtained by optimizing the places where the first to fourth windings 11 to 14 are wound on the core 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a composite coil in which a plurality of coils are integrated, and a noise filter that suppresses noise by using a function of the composite coil as a choke coil.

  Conventionally, a noise filter (line filter) has been used to suppress noise propagating through an AC power supply line or a signal line. Noise that propagates through two conductive lines such as an AC power line and a signal line includes normal mode (differential mode) noise that causes a potential difference between the two conductive lines and two conductive lines in the same phase. There is common mode noise to propagate.

  FIG. 22 shows an example of a circuit configuration of a conventional noise filter. This noise filter includes two common mode choke coils 110 and 120, two Y capacitors Cy1 and Cy2, and an X capacitor Cx1. The first common mode choke coil 110 has a first core 110A and a first winding 111 and a second winding 112 wound around the first core 110A in common. When the first winding 111 is wound around the first core 110A, the first inductor L1 is formed on the first conductive wire 101, and the second winding 112 is wound around the first core 110A. Thus, the second inductor L2 is formed on the second conductive line 102. The second common mode choke coil 120 has a second core 120A and a third winding 113 and a fourth winding 114 wound around the second core 120A in common. When the third winding 113 is wound around the second core 120A, the third inductor L3 is formed on the first conductive wire 101, and the fourth winding 114 is wound around the second core 120A. Thus, a fourth inductor L4 is formed on the second conductive line. One end of the first Y capacitor Cy1 is connected between the first winding 111 and the third winding 113, and the other end is grounded. The second Y capacitor Cy2 has one end connected between the second winding 112 and the fourth winding 114, and the other end grounded. The X capacitor Cx <b> 1 has one end connected to the first conductive line 101 and the other end connected to the second conductive line 102. Lx1 and Lx2 represent leakage inductance components generated by the leakage magnetic flux of the common mode choke coils 110 and 120. Incidentally, leakage inductance components are formed on the first and second conductive lines by the leakage flux of the first common mode choke coil 110, and the first and second leakage fluxes of the second common mode choke coil 120 are also formed. The leakage inductance component is formed on each of the conductive wires. Here, the leakage inductance components formed on the first conductive wire are collectively expressed as Lx1, and the leakage inductance formed on the second conductive wire is shown. The components are combined into one and represented as Lx2.

  In this noise filter, common mode noise is attenuated by the two common mode choke coils 110 and 120 and the Y capacitors Cy1 and Cy2. Specifically, the common mode noise flowing through the first conductive line 101 is attenuated by the first inductor L1 or the third inductor L3 and the Y capacitor Cy1. The common mode noise flowing through the second conductive line 102 is attenuated by the second inductor L2 or the fourth inductor L4 and the Y capacitor Cy2. On the other hand, the common mode choke coils 110 and 120 themselves have a small effect as an inductor for normal mode signals. The attenuation effect of normal mode noise is obtained by the leakage inductance components Lx1 and Lx2, the X capacitor Cx1, and the Y capacitors Cy1 and Cy2 connected in series. Specifically, a filter formed by Y capacitors Cy1 and Cy2 connected in series with a leakage inductance component by the common mode choke coil 110, a filter formed by a leakage inductance component by the common mode choke coil 120 and an X capacitor Cx1 Forms a two-stage filter, which attenuates normal mode noise.

A general common mode choke coil has a small effect as an inductor for a normal mode signal. However, Patent Document 1 discloses a composite coil capable of generating an inductance component for a common mode signal and an inductance component for a normal mode signal. Is disclosed. In the composite coil described in Patent Document 1, two cores having different shapes are stacked in the vertical direction, and two windings are wound so as to straddle the two stacked cores. And an inductance component for the normal mode signal.
Japanese Patent No. 2729937

  However, in the configuration of the noise filter shown in FIG. 22, two common mode choke coils 110 and 120 are required, so that it is difficult to reduce the size. Therefore, as shown in the equivalent circuit of FIG. 23, it is conceivable to form the choke coil 130 in which the two common mode choke coils 110 and 120 are integrated by winding each winding around one core 130A. In this case, specifically, as shown in FIG. 24, as a core 130A, an EE core, an EI core, or the like is used to form a Japanese-shaped core having a middle leg portion 131 and two outer leg portions 132, 133. It is conceivable to form and wind each winding around the two outer legs 132 and 133. For example, as shown in the figure, one outer leg portion 132 is wound so that the first winding 111 and the second winding 112 are provided side by side, and the other outer leg portion 133 is wound with the third winding 113. A configuration in which the fourth winding 114 is provided side by side is conceivable.

  In FIG. 24, the solid line arrows shown in the respective winding portions indicate the direction of the magnetic flux in the common mode, and the broken line arrows indicate the direction of the magnetic flux in the normal mode. As shown in the figure, with respect to the common mode signal 141C, the direction of the magnetic flux Φ1 by the first winding 111 and the second winding 112 and the third winding 113 and the fourth winding 114 in the middle leg portion 131. The direction of the magnetic flux Φ2 due to the magnetic flux Φ2 is the same, and the magnetic fluxes Φ1 and Φ2 do not cancel each other. On the other hand, for the normal mode signal 141N, the direction of the magnetic flux Φ11 by the first winding 111 and the direction of the magnetic flux Φ12 by the second winding 112 are opposite to each other and cancel each other. Similarly, the direction of the magnetic flux Φ13 by the third winding 113 and the direction of the magnetic flux Φ14 by the fourth winding 114 are opposite to each other and cancel each other. Thereby, the inductance value with respect to the normal mode signal 141N becomes small. In the case of this configuration, the leakage magnetic flux with respect to the normal mode signal 141N also acts in the direction of canceling out. That is, since the first winding 111 and the second winding 112 are arranged side by side in one outer leg 132, the direction of the leakage magnetic flux by the first winding 111 and the second winding The directions of the leakage magnetic flux due to 112 are opposite to each other and cancel each other. Similarly, the direction of the leakage flux by the third winding 113 and the direction of the leakage flux by the fourth winding 114 are opposite to each other and cancel each other. As a result, the leakage inductance value for the normal mode signal 141N is also reduced. For this reason, there is a problem that the attenuation effect on the normal mode noise when combined with the X capacitor Cx1 is also reduced.

  In the case of downsizing, a method of winding the windings of the two common mode choke coils 110 and 120 around one annular core like a square shape is conceivable. And the second and fourth windings 112 and 114 are strongly coupled, and mutual inductance is formed in series with the Y capacitors Cy1 and Cy2. As a result, the cut-off frequency is low. There is a problem that the desired characteristics cannot be obtained due to movement to the side.

  Further, although the composite coil described in Patent Document 1 can generate an inductance component for the common mode signal and an inductance component for the normal mode signal, the AC power component and the data signal flowing in the AC power line and the signal line can be generated. There is a problem that the core is saturated by the normal mode signal of the component, and a sufficient inductance value for normal mode noise cannot be obtained.

  The present invention has been made in view of such a problem, and an object thereof is to provide a composite coil and a noise filter that can obtain necessary inductance values for both a common mode signal and a normal mode signal. is there.

  A composite coil according to the present invention includes a core having a middle leg portion and first to fourth sides substantially orthogonal to the middle leg portion, a first winding wound around the first side of the core, A second winding wound around the second side; a third winding wound around the third side of the core; and a fourth winding wound around the fourth side of the core. ing. The first side and the second side are respectively connected to both ends of the middle leg portion so as to be opposed to each other, and the third side and the fourth side are respectively both ends of the middle leg portion. And the first leg and the first and second sides form a first magnetic path for the first and second windings, and the middle leg. A second magnetic path for the third and fourth windings is formed by the third and fourth sides, and the first to the second magnetic paths are oriented in the same direction in the middle leg portion with respect to the common mode signal. Four windings are wound around the first to fourth sides of the core.

  In the composite coil according to the present invention, each winding is wound with the same core, and a first magnetic path for the first and second windings is formed by the middle leg portion and the first and second sides. A choke having a configuration in which two common mode choke coils are integrated by forming a second magnetic path for the third and fourth windings by the middle leg portion and the third and fourth sides. A coil is formed. In this case, the first magnetic path and the second magnetic path are formed so as to share the middle leg portion, and each winding is arranged so that the direction of the magnetic flux with respect to the common mode signal is the same direction in the middle leg portion. By winding the wire, the magnetic flux in the first magnetic path and the magnetic flux in the second magnetic path do not cancel each other, and each inductor by each winding functions as a choke coil independently. In addition, since the first winding and the second winding are wound around the first side and the second side facing each other, the first winding and the second winding are wound on one side. Compared with the case of winding together with a wire, the effect of the leakage magnetic flux canceling out by the first and second windings on the normal mode signal is reduced. Similarly, since the third winding and the fourth winding are wound around the third side and the fourth side facing each other, the third winding and the fourth winding are wound on one side. Compared with the case of winding together with the winding, the action of the leakage magnetic fluxes canceled by the third and fourth windings on the normal mode signal is reduced. This increases the leakage inductance value for the normal mode signal. In this way, necessary inductance values are obtained for both the common mode signal and the normal mode signal.

In the composite coil according to the present invention, the core includes, for example, an H-shaped core having a middle leg portion at the center and two U-shaped integrated with the H-shaped core so as to sandwich both ends of the H-shaped core. It can be configured to have a core. In this case, the H-shaped core and the U-shaped core may be disposed at different positions in the vertical cross section.
When the H-shaped core and the U-shaped core are arranged at different positions in the vertical cross section, it is easy to secure a component arrangement space in which circuit components such as capacitors are arranged in the vertical cross section. Thereby, when a noise filter is comprised, it becomes easy to aim at size reduction of the whole.

In addition, the core may be configured to include an I-shaped core serving as a middle leg portion and two U-shaped cores integrated with the I-shaped core so as to sandwich the I-shaped core. In this case, one end of the I-shaped core and one end of the two U-shaped cores are inserted, the first bobbin around which the first and third windings are wound, and the other end of the I-shaped core And the second bobbin around which the second and fourth windings are wound, and the first bobbin and the second bobbin form an I shape. The core and the two U-shaped cores may be integrated.
In the case of the configuration in which the I-shaped core and the two U-shaped cores are integrated by the first bobbin and the second bobbin, for example, a bobbin is arranged on each of the first to fourth sides and each winding is arranged. Compared to the wound configuration, the number of parts is reduced.

  The core has an H-shaped core having a middle leg portion at the center, a U-shaped core disposed on one end of the H-shaped core and integrated with the H-shaped core, and the other end of the H-shaped core. It may be configured to have an I-shaped core disposed on the side and integrated with the H-shaped core.

  The noise filter according to the present invention is a noise filter including a composite coil having a function as a choke coil, and the composite coil has a middle leg portion and first to fourth sides substantially orthogonal to the middle leg portion. A core, a first winding wound around the first side of the core, a second winding wound around the second side of the core, and a third winding wound around the third side of the core It has a winding and a fourth winding wound around the fourth side of the core. The first side and the second side are respectively connected to both ends of the middle leg portion so as to be opposed to each other, and the third side and the fourth side are respectively both ends of the middle leg portion. And the first leg and the first and second sides form a first magnetic path for the first and second windings, and the middle leg. A second magnetic path for the third and fourth windings is formed by the third and fourth sides, and the first to the second magnetic paths are oriented in the same direction in the middle leg portion with respect to the common mode signal. Four windings are wound around the first to fourth sides of the core.

  In the noise filter according to the present invention, in the composite coil, each winding is wound with the same core, and the first magnetic path for the first and second windings by the middle leg portion and the first and second sides. And a second magnetic path for the third and fourth windings is formed by the middle leg portion and the third and fourth sides, thereby integrating the two common mode choke coils. A choke coil having the above-described configuration is formed. In this case, the first magnetic path and the second magnetic path are formed so as to share the middle leg portion, and each winding is arranged so that the direction of the magnetic flux with respect to the common mode signal is the same direction in the middle leg portion. By winding the wire, the magnetic flux in the first magnetic path and the magnetic flux in the second magnetic path do not cancel each other, and each inductor by each winding functions as a choke coil independently. In addition, since the first winding and the second winding are wound around the first side and the second side facing each other, the first winding and the second winding are wound on one side. Compared with the case of winding together with a wire, the effect of the leakage magnetic flux canceling out by the first and second windings on the normal mode signal is reduced. Similarly, since the third winding and the fourth winding are wound around the third side and the fourth side facing each other, the third winding and the fourth winding are wound on one side. Compared with the case of winding together with the winding, the action of the leakage magnetic fluxes canceled by the third and fourth windings on the normal mode signal is reduced. This increases the leakage inductance value for the normal mode signal. In this way, necessary inductance values are obtained for both the common mode signal and the normal mode signal, and both the common mode noise and the normal mode noise are satisfactorily suppressed.

In the noise filter according to the present invention, the composite coil further includes at least one capacitor, and the composite coil has an H-shaped core having a middle leg portion at the center and an H-shaped core sandwiching both ends of the H-shaped core. You may have two U-shaped cores integrated. The H-shaped core and the U-shaped core are arranged at different positions in the vertical cross section so that the component arrangement space is formed in the vertical cross section, and the capacitor is arranged in the component arrangement space. Also good.
In the case of this configuration, the composite coil and the capacitor are integrated in the vertical cross section, and the overall size can be easily reduced.

  According to the composite coil of the present invention, the first to fourth windings are wound around the core having the middle leg portion and the first to fourth sides substantially orthogonal to the middle leg portion, Since optimization is made, necessary inductance values can be obtained for both the common mode signal and the normal mode signal.

  According to the noise filter of the present invention, the first to fourth windings are wound around the core having the middle leg portion and the first to fourth sides substantially orthogonal to the middle leg portion, Since the optimized composite coil is used as a choke coil, the required inductance value can be obtained for both the common mode signal and the normal mode signal. Both can be satisfactorily attenuated.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a basic configuration of a composite coil according to an embodiment of the present invention. FIG. 2 shows an equivalent circuit of a choke coil formed by the composite coil. The composite coil includes a core 10, a first winding 11, a second winding 12, a third winding 13, and a fourth winding 14 wound around the core 10. The core 10 has a Japanese character shape as a whole, and includes a middle leg portion 20, a first side 21, a second side 22, a third side 23, and a fourth side substantially orthogonal to the middle leg portion 20. 24. The first side 21 and the second side 22 are respectively connected to both end portions of the middle leg portion 20 and provided so as to face each other on one side (left side in the figure). The third side 23 and the fourth side 24 are respectively connected to both end portions of the middle leg portion 20 and provided to face each other on the other side (right side in the drawing).

  The first winding 11 is wound around the first side 21 of the core 10. The second winding 12 is wound around the second side 22 of the core 10. When the first winding 11 is wound around the first side 21, the first inductor L 1 is formed on the first conductive wire 1, and the second winding 12 is wound around the second side 22. Thus, the second inductor L2 is formed on the second conductive line 2. The third winding 13 is wound around the third side 23 of the core 10. The fourth winding 14 is wound around the fourth side 24 of the core 10. When the third winding 13 is wound around the third side 23, the third inductor L 3 is formed on the first conductive wire 1, and the fourth winding 14 is wound around the fourth side 24. Thus, a fourth inductor L4 is formed on the second conductive line 2.

  In the core 10, a first magnetic path for the first winding 11 and the second winding 12 is formed by a substantially one side portion including the first side 21, the middle leg portion 20, and the second side 22. . Further, in the core 10, the second magnetic path with respect to the third winding 13 and the fourth winding 14 by the other substantially one side portion including the third side 23, the middle leg portion 20, and the fourth side 24. Is formed. Thus, the first magnetic path and the second magnetic path are formed so as to share the middle leg portion 20. In addition, the first to fourth windings 11 to 14 are the third winding and the direction of the magnetic flux Φ1 by the first winding 11 and the second winding 12 with respect to the common mode signal 3C in the middle leg portion 20. 13 and the fourth winding 14 are wound around the first to fourth sides 21 to 24 of the core 10 so that the direction of the magnetic flux Φ2 is the same.

  In FIG. 1, solid arrows shown in the respective winding portions indicate the direction of magnetic flux in the common mode, and broken arrows indicate the direction of magnetic flux in the normal mode. In FIG. 2, Lx1 and Lx2 represent leakage inductance components generated by the leakage magnetic flux of the first to fourth windings 11-14.

Next, the operation of the composite coil according to the present embodiment will be described.
In this composite coil, each winding is wound around the same core 10 in the shape of a Japanese character, and in the core 10, by a substantially one side portion including the first side 21, the middle leg portion 20, and the second side 22. The first magnetic path is formed, and the second magnetic path is formed by the other substantially one side portion including the third side 23, the middle leg portion 20, and the fourth side 24. A choke coil having a configuration in which two common mode choke coils (a common mode choke coil by the first and second windings 11 and 12 and a common mode choke coil by the third and fourth windings 13 and 14) are integrated. It is formed. In this composite coil, as shown in FIG. 1, for the common mode signal 3C, the direction of the magnetic flux Φ1 and the third winding by the first winding 11 and the second winding 12 in the middle leg portion 20 are applied. The direction of the magnetic flux Φ2 by the line 13 and the fourth winding 14 is the same, and the magnetic fluxes Φ1 and Φ2 do not cancel each other, and the inductors L1 to L4 by the windings 11 to 14 each function as a choke coil independently. .

  On the other hand, for the normal mode signal 3N, in the core 10, the direction of the magnetic flux Φ11 by the first winding 11 and the direction of the magnetic flux Φ12 by the second winding 12 are opposite to each other and cancel each other. Similarly, in the core 10, the direction of the magnetic flux Φ13 by the third winding 13 and the direction of the magnetic flux Φ14 by the fourth winding 14 are opposite to each other and cancel each other. As a result, the inductance value with respect to the normal mode signal 141N is reduced and the saturation with respect to the magnetic flux in the core 10 is eliminated. However, in this composite coil, the first winding 11 and the second winding 12 are wound around the first side 21 and the second side 22 facing each other. Compared with the case where the winding 11 and the second winding 12 are wound side by side (see FIG. 24), the leakage magnetic flux by the first and second windings 11 and 12 cancels each other with respect to the normal mode signal 3N. The effect is reduced. Similarly, since the third winding 13 and the fourth winding 14 are wound around the third side 23 and the fourth side 24 that face each other, the third winding is provided on one side. Compared with the case of winding 13 and the fourth winding 14 side by side, the action of the leakage magnetic fluxes canceled by the third and fourth windings 13 and 14 on the normal mode signal 3N is reduced. As a result, the values of the leakage inductances Lx1 and Lx2 for the normal mode signal 3N increase. Thus, necessary inductance values are obtained for both the common mode signal 3C and the normal mode signal 3N. For this reason, when the noise filter is configured by combining the X capacitors, it is possible to improve the attenuation effect on the normal mode noise.

  FIG. 4 shows the results (examples) of measuring the values of leakage inductances Lx1 and Lx2 obtained by this composite coil. FIG. 3 shows an equivalent circuit of the circuit used for the measurement. FIG. 4 also shows a measurement result obtained by the composite coil having the configuration shown in FIG. 24 as a comparative example. 4, k12 represents a coupling coefficient between the first winding 11 and the second winding 12, as shown in FIG. k13 indicates a coupling coefficient between the first winding 11 and the third winding 13. k14 represents a coupling coefficient between the first winding 11 and the fourth winding 14. As can be seen from the measurement results, in this composite coil, the coupling coefficients k12, k13, k14 between the windings are smaller than in the configuration of the comparative example. From this, it can be seen that in this composite coil, the coupling between the windings is weaker and more leakage magnetic flux is generated than in the configuration of the comparative example. Thereby, the values of the leakage inductances Lx1 and Lx2 are larger than those of the configuration of the comparative example.

As described above, according to the composite coil according to the present embodiment, with respect to the core 10 having the middle leg portion 20 and the first to fourth sides 21 to 24 substantially orthogonal to the middle leg portion 20, Since the first to fourth windings 11 to 14 are wound and the winding positions are optimized, necessary inductance values can be obtained for both the common mode signal and the normal mode signal.
<Specific configuration example of composite coil>

  FIG. 5A, FIG. 5B, FIG. 6A, and FIG. 6B show a first specific configuration example of this composite coil. FIG. 5A shows an exploded plan view (top view) and FIG. 5B shows an exploded side view before the components of the composite coil are integrated. FIG. 6A shows a plan view (top view) in a state where the constituent elements of the composite coil are integrated, and FIG. 6B shows a side view.

  In this configuration example, the core 10 is integrated with the H-shaped core 30H having a portion that becomes the middle leg portion 20 at the center and the H-shaped core 30H so as to sandwich both ends of the H-shaped core 30H. This is composed of two U-shaped cores 31U and 32U. In this configuration example, the first winding 11 and the second winding 12 are wound so as to straddle the connecting portion between the H-shaped core 30H and one U-shaped core 31U, and the third winding 13 and The fourth winding 14 is wound so as to straddle the connecting portion between the H-shaped core 30H and the other U-shaped core 32U. In this case, the H-shaped core 30H and the U-shaped cores 31U and 32U may be connected via a bobbin, and each winding may be wound around the bobbin. In this configuration example, as can be seen from FIGS. 5B and 6B, the vertical direction (Z direction) between the H-shaped core 30H and the two U-shaped cores 31U and 32U when viewed from the side. The vertical arrangement positions in the cross section are substantially the same.

  FIGS. 7A, 7B, 8A, and 8B show a second specific configuration example of the composite coil. FIG. 7A shows an exploded plan view (top view) and FIG. 7B shows an exploded side view before the components of the composite coil are integrated. FIG. 8A shows a plan view (top view) in a state where the constituent elements of the composite coil are integrated, and FIG. 8B shows a side view.

  In this configuration example, the core 10 is composed of an H-shaped core 30H and two U-shaped cores 31U and 32U, as in the first configuration example. However, as can be seen from FIGS. 7B and 8B, the H-shaped core 30H and the two U-shaped cores 31U and 32U are located at different positions in the vertical direction in the cross section in the vertical direction (Z direction). Has been placed. In the illustrated example, the H-shaped core 30H is disposed on the upper side and the two U-shaped cores 31U and 32U are disposed on the lower side in the vertical cross section. Then, the H-shaped core 30H and the one U-shaped core 31U are integrated so that the leg on one side of the H-shaped core 30H and the leg of the one U-shaped core 31U partially overlap in the plane direction. It has a structure. Similarly, the H-shaped core 30H and the other U-shaped core 32U are integrated so that the leg of the other side of the H-shaped core 30H and the leg of the other U-shaped core 32U partially overlap in the plane direction. It has a structure that is In the case of this configuration example, the H-shaped core 30H and the two U-shaped cores 31U and 32U are arranged at different positions in the vertical cross section, so that circuit components such as a capacitor in the vertical cross section. It is easy to secure a part arrangement space for arranging the parts. For example, as shown in the figure, the component placement space 40 can be formed below the H-shaped core 30H, and the component placement spaces 41 and 42 can be formed above the two U-shaped cores 31U and 32U. By disposing a capacitor component or the like in this portion, it is easy to reduce the overall size when configuring a noise filter.

  FIG. 9A, FIG. 9B, FIG. 10A, and FIG. 10B show a third specific configuration example of this composite coil. FIG. 9A shows an exploded plan view (top view) and FIG. 9B shows an exploded side view before the components of the composite coil are integrated. FIG. 10A is a plan view (top view) and FIG. 10B is a side view showing the components of the composite coil in an integrated state.

  In this configuration example, the core 10 includes an I-shaped core 30I serving as the middle leg portion 20 and two U-shaped cores 31U integrated with the I-shaped core 30I so as to sandwich both ends of the I-shaped core 30I. 32U. In this configuration example, the first winding 11 and the second winding 12 are wound around opposing leg portions of one U-shaped core 31U, and the third winding 13 and the fourth winding 14 are the other. The U-shaped core 32U is wound around opposing leg portions.

  FIGS. 11A, 11B, 12A, and 12B show a fourth specific configuration example of the composite coil. FIG. 11A shows an exploded plan view (top view) and FIG. 11B shows an exploded side view in a state before the components of the composite coil are integrated. FIG. 12A shows a plan view (top view) and FIG. 12B shows a side view in a state where the components of the composite coil are integrated.

  In this configuration example, the core 10 is integrated with the H-shaped core 30H, which is disposed on one end side of the H-shaped core 30H having a portion that becomes the middle leg 20 at the center, and the H-shaped core 30H. The U-shaped core 31U and the I-shaped core 32I which is disposed on the other end side of the H-shaped core 30H and integrated with the H-shaped core 30H. In this configuration example, the first winding 11 and the second winding 12 are wound so as to straddle the connection portion between the H-shaped core 30H and the U-shaped core 31U. Further, the third winding 13 and the fourth winding 14 are wound around opposing leg portions on the other end side of the H-shaped core 30H.

  FIGS. 13A, 13B, 13C, 14A, and 14B show a fifth specific configuration example of the composite coil. FIG. 13A shows an exploded plan view (top view) and FIG. 13B shows an exploded side view of the composite coil before the components are integrated. FIG. 13C is a partial side view.

  In this configuration example, the configuration of the core 10 is the same as that of the third configuration example, and includes an I-shaped core 30I and two U-shaped cores 31U and 32U. However, in this configuration example, first and second bobbins 51 and 52 are provided at a connection portion between the I-shaped core 30I and the two U-shaped cores 31U and 32U. The first bobbin 51 has a hollow cylindrical shape, and an opening 51A is provided at the center, and openings 51B and 51C are provided at both ends. Similarly, the second bobbin 52 has a hollow cylindrical shape, and has an opening 52A at the center and openings 52B and 52C at both ends. FIG. 13C shows a state in which the second bobbin 52 is viewed from the opening 52A side in the center.

In this configuration example, one end of the I-shaped core 30I is inserted into the opening 51A of the first bobbin 51, and one end of the two U-shaped cores 31U and 32U is inserted into the openings 51B and 51C at both ends. The The other end of the I-shaped core 30I is inserted into the opening 52A of the second bobbin 52, and the other ends of the two U-shaped cores 31U and 32U are inserted into the openings 52B and 52C at both ends. . Thereby, the I-shaped core 30I and the two U-shaped cores 31U and 32U are integrated via the first and second bobbins 51 and 52. The first bobbin 51 is wound with the first and third windings 11 and 13, and the second bobbin 52 is wound with the second and fourth windings 12 and 14. In the case of this configuration, for example, compared to a configuration in which a bobbin is arranged in each of four connection portions of the I-shaped core 30I and the two U-shaped cores 31U and 32U, and each winding is wound around each part, The score can be reduced. Further, the I-shaped core 30I can be fixed by the first and second bobbins 51 and 52, and the I-shaped core 30I can be prevented from being displaced.
<Specific configuration example of noise filter>

  Next, a specific configuration example of the noise filter using the composite coil according to the present embodiment will be described.

  FIG. 16A is a plan view (top view) showing a specific configuration example of the noise filter, and FIG. 16B is a side view. FIG. 15 shows an equivalent circuit of this noise filter. First, the circuit configuration of the noise filter will be described with reference to FIG. This noise filter has a configuration in which two X capacitors Cx1 and Cx2 and two Y capacitors Cy1 and Cy2 are connected to a choke coil formed by the composite coil according to the present embodiment. One end of the first Y capacitor Cy1 is connected between the first winding 11 and the third winding 13, and the other end is grounded. One end of the second Y capacitor Cy2 is connected between the second winding 12 and the fourth winding 14, and the other end is grounded. The first X capacitor Cx1 has one end connected to the first conductive line 1 and the other end connected to the second conductive line 2 on the side where the third winding 13 and the fourth winding 14 are provided. It is connected to the. The second X capacitor Cx2 has one end connected to the first conductive line 1 and the other end connected to the second conductive line 2 on the side where the first winding 11 and the second winding 12 are provided. It is connected to the. In FIG. 15, Lx1 and Lx2 represent leakage inductance components generated by the leakage magnetic flux of the first to fourth windings 11-14.

  Next, a specific configuration will be described. The configuration example shown in FIGS. 16A and 16B is a second configuration example of the composite coil according to the present embodiment (FIGS. 7A, 7B, and 8A). 8 (B)), the core 10 is composed of an H-shaped core 30H and two U-shaped cores 31U and 32U, and the H-shaped cores 30H and 2H are applied. The two U-shaped cores 31U and 32U are arranged at different positions in the vertical direction in the cross section in the vertical direction. A component placement space 40 is formed below the H-shaped core 30H, and component placement spaces 41 and 42 are formed above the two U-shaped cores 31U and 32U. The H-shaped core 30H and the two U-shaped cores 31U and 32U are integrated via four bobbins 61 to 64. The first winding 11 is wound around the first bobbin 61, the second winding 12 is wound around the second bobbin 62, and the third winding 13 is wound around the third bobbin 63. The fourth winding 14 is wound around the fourth bobbin 64.

  The two X capacitors Cx1 and Cx2 are constituted by, for example, lead type capacitors. The second X capacitor Cx2 is arranged in the component arrangement space 41 on the upper side of one U-shaped core 31U, and the first X capacitor Cx1 is arranged in the component arrangement space 42 on the upper side of the other U-shaped core 32U. Yes. The two Y capacitors Cy <b> 1 and Cy <b> 2 are constituted by, for example, chip type capacitors, and are arranged in the component arrangement space 40 below the H-shaped core 30 </ b> H. The composite coil component and each capacitor component are mounted on the surface of the substrate 60. In this configuration example, the arrangement of the H-shaped core 30H and the two U-shaped cores 31U and 32U is devised to form a component arrangement space, and the capacitor component is arranged there. The composite coil and the capacitor component are integrated to reduce the overall size.

  Next, transmission characteristics of a noise filter using the composite coil according to the present embodiment will be described. FIG. 20 shows an example of transmission characteristics in the common mode of the noise filter according to the present embodiment, and FIG. 21 shows an example of transmission characteristics in the normal mode. 20 and FIG. 21, the horizontal axis represents frequency (Hz) and the vertical axis represents attenuation (dB). FIG. 17 shows an equivalent circuit of a circuit used for simulation of transmission characteristics. The second X capacitor Cx2 is omitted from the circuit configuration shown in FIG. FIG. 19 shows circuit values used for the simulation. K12 represents a coupling coefficient between the first winding 11 and the second winding 12, as shown in FIG. k13 indicates a coupling coefficient between the first winding 11 and the third winding 13. k14 represents a coupling coefficient between the first winding 11 and the fourth winding 14. k23 represents a coupling coefficient between the second winding 12 and the third winding 13. k24 represents a coupling coefficient between the second winding 12 and the fourth winding 24. k34 indicates a coupling coefficient between the third winding 13 and the fourth winding 14.

  As Comparative Example 1, transmission characteristics when the equivalent circuit is the same but the composite coil has the configuration shown in FIG. 24 (configuration in which two windings are provided on one leg) are also shown. Further, as Comparative Example 2, transmission characteristics when the circuit is configured as shown in FIG. 22 (configuration having two common mode choke coils 110 and 120) are also shown. The difference in circuit value between the noise filter according to the present embodiment and the noise filters of Comparative Examples 1 and 2 appears as a difference in coupling coefficient between windings as shown in FIG. The noise filter according to the present embodiment does not show much difference with respect to the noise filter of Comparative Example 1 with respect to the transmission characteristics in the common mode (FIG. 20). However, with respect to the transmission characteristics in the normal mode (FIG. 21), the noise filter according to the present embodiment has an attenuation pole on the low frequency side compared to the noise filters of Comparative Examples 1 and 2. This is because in the noise filter according to the present embodiment, the leakage inductance component due to the leakage magnetic flux is large. Comparative Example 1 and Comparative Example 2 have the same transmission characteristics in the normal mode. Thus, in the noise filter using the composite coil according to the present embodiment, an attenuation pole can be generated in the transmission characteristics in the normal mode.

  In addition, this invention is not limited to the said embodiment, A various change is possible. For example, the specific configuration of the core 10 is not limited to the specific example described above, and a configuration in which cores of other shapes are combined is also possible. The specific configuration of the noise filter is not limited to the configuration shown in FIGS. 16A and 16B, and may be a configuration using another specific example of the composite coil described above.

It is a block diagram which shows the basic composition of the composite coil which concerns on one embodiment of this invention. It is a circuit diagram which shows the equivalent circuit of the composite coil which concerns on one embodiment of this invention. It is a circuit diagram which shows the measuring circuit of leakage inductance. It is explanatory drawing which shows the measurement result of leakage inductance. BRIEF DESCRIPTION OF THE DRAWINGS The 1st specific structural example of the composite coil which concerns on one embodiment of this invention is shown, (A) is an exploded plan view (top view), (B) is an exploded side view. The 1st specific structural example of the composite coil which concerns on one embodiment of this invention is shown, (A) is a top view (top view), (B) is a side view. The 2nd example of a specific structure of the composite coil which concerns on one embodiment of this invention is shown, (A) is an exploded plan view (top view), (B) is an exploded side view. The 2nd example of a specific structure of the composite coil which concerns on one embodiment of this invention is shown, (A) is a top view (top view), (B) is a side view. The 3rd example of a specific structure of the composite coil which concerns on one embodiment of this invention is shown, (A) is an exploded plan view (top view), (B) is an exploded side view. The 3rd example of a specific structure of the composite coil which concerns on one embodiment of this invention is shown, (A) is a top view (top view), (B) is a side view. The 4th example of a specific structure of the composite coil which concerns on one embodiment of this invention is shown, (A) is an exploded plan view (top view), (B) is an exploded side view. The 4th example of a specific structure of the composite coil which concerns on one embodiment of this invention is shown, (A) is a top view (top view), (B) is a side view. The 5th example of a specific composition of the compound coil concerning one embodiment of the present invention is shown, (A) is an exploded top view (top view), (B) is an exploded side view, (C) is a partial side view. The 5th example of a specific structure of the composite coil which concerns on one embodiment of this invention is shown, (A) is a top view (top view), (B) is a side view. It is an equivalent circuit diagram which shows the circuit structure of the noise filter using the composite coil which concerns on one embodiment of this invention. The specific structural example of the noise filter using the composite coil which concerns on one embodiment of this invention is shown, (A) is a top view (top view), (B) is a side view. It is an equivalent circuit diagram of a circuit used for simulation of transmission characteristics. It is explanatory drawing about a coupling coefficient. It is explanatory drawing which shows the circuit value used for the simulation of the transmission characteristic. It is a characteristic view which shows the simulation result of the transmission characteristic in a common mode. It is a characteristic view which shows the simulation result of the transmission characteristic in normal mode. It is a circuit diagram which shows an example of the circuit structure of the conventional noise filter. It is a circuit diagram which shows the equivalent circuit of the composite coil which integrated two choke coils. It is a block diagram which shows an example of the composite coil which integrated two choke coils.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... 1st conductive wire, 2 ... 2nd conductive wire, 3C ... Normal mode signal, 3N ... Common mode signal, 11 ... 1st winding, 12 ... 3rd winding, 14 ... 4th winding 20 ... middle leg, 21 ... first side, 22 ... second side, 23 ... third side, 24 ... fourth side, 30H ... H-shaped core, 30I ... I-shaped core, 31U, 32U ... U-shaped core, 51 ... first bobbin, 52 ... second bobbin.

Claims (8)

A core having a middle leg portion and first to fourth sides substantially orthogonal to the middle leg portion;
A first winding wound around the first side of the core;
A second winding wound around the second side of the core;
A third winding wound around the third side of the core;
A fourth winding wound around the fourth side of the core;
The first side and the second side are respectively connected to both ends of the middle leg portion so as to be opposed to each other, and the third side and the fourth side are respectively Connected to both ends of the leg and provided to face each other,
The middle leg portion and the first and second sides form a first magnetic path for the first and second windings, and the middle leg portion and the third and fourth sides To form the second magnetic path for the third and fourth windings, and the first to fourth windings so that the direction of the magnetic flux with respect to the common mode signal is the same in the middle leg portion. Is wound around the first side to the fourth side of the core. The core has an H-shaped core having a portion serving as the middle leg at the center, and two U-shaped cores integrated with the H-shaped core so as to sandwich both end portions of the H-shaped core. The composite coil according to claim 1. The composite coil according to claim 2, wherein the H-shaped core and the U-shaped core are arranged at different positions in a cross section in a vertical direction. The said core has an I-shaped core used as the said middle leg part, and two U-shaped cores integrated with the said I-shaped core so that the said I-shaped core may be pinched | interposed. The composite coil as described. A first bobbin around which one end of the I-shaped core and one end of the two U-shaped cores are inserted and the first and third windings are wound;
A second bobbin on which the other end of the I-shaped core and the other end of the two U-shaped cores are inserted and on which the second and fourth windings are wound;
The composite coil according to claim 4, wherein the I-shaped core and the two U-shaped cores are integrated with each other by the first bobbin and the second bobbin. The core includes an H-shaped core having a central leg portion at a central portion, a U-shaped core disposed on one end side of the H-shaped core and integrated with the H-shaped core, and the H-shaped core. The composite coil according to claim 1, further comprising: an I-shaped core disposed on the other end side and integrated with the H-shaped core. A noise filter including a composite coil having a function as a choke coil,
The composite coil is:
A core having a middle leg portion and first to fourth sides substantially orthogonal to the middle leg portion;
A first winding wound around the first side of the core;
A second winding wound around the second side of the core;
A third winding wound around the third side of the core;
A fourth winding wound around the fourth side of the core;
The first side and the second side are respectively connected to both ends of the middle leg portion so as to be opposed to each other, and the third side and the fourth side are respectively Connected to both ends of the leg and provided to face each other,
The middle leg portion and the first and second sides form a first magnetic path for the first and second windings, and the middle leg portion and the third and fourth sides To form the second magnetic path for the third and fourth windings, and the first to fourth windings so that the direction of the magnetic flux with respect to the common mode signal is the same in the middle leg portion. Is wound around the first side to the fourth side of the core. Further comprising at least one capacitor;
The composite coil includes an H-shaped core having a central leg portion at the center, and two U-shaped cores integrated with the H-shaped core so as to sandwich both end portions of the H-shaped core. Have
The H-shaped core and the U-shaped core are arranged at different positions in the vertical cross section so that a component arrangement space is formed in the vertical cross section, and the capacitor is arranged in the component arrangement space. The noise filter according to claim 7, wherein:

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