Wiring core structure, semiconductor evaluation device and semiconductor device

A wound wire is wound around a core assembly so that both ends are short-circuited. In a coupling pin insertion state in which a coupling pin is inserted in a through hole of the core assembly, outer-peripheral space parts of respective divided core portions of the core assembly are disposed so as to overlap in plan view. Consequently, an air gap is formed in a part of a side surface of the core assembly. Before formation of a covering member, a main wire is caused to pass through the air gap and is thus disposed in a wiring hole of the core assembly. Then, the covering member for closing the air gap is provided on an outer peripheral surface side of the core assembly including the air gap so that a core structure is obtained.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a wiring core structure provided in a wiring region where a parasitic inductance is to be suppressed in a large current circuit, a high frequency circuit and the like, that is, a wiring region to be a parasitic-inductance suppression target.

Description of the Background Art

In a large current circuit and a high frequency circuit, it is necessary to reduce a wiring parasitic L (inductance). An inductance L of a wiring cable, an applied current I, and a magnetic flux ϕ generated around the wiring cable have a relationship of {L=ϕ/1}.

In other words, the wiring parasitic L is caused by the magnetic flux generated around a wire. As a countermeasure to be taken against the wiring parasitic L, conventionally, the wiring is shortened as greatly as possible. Alternatively, a method using a twisted wire, a parallel plate or the like is utilized to cancel the magnetic flux.

Moreover, in order to suppress the wiring parasitic L, Japanese Patent Application Laid-Open No. 2001-313216 or the like discloses a noise-current absorbing tool that surrounds an outer peripheral part of a wire to absorb a noise getting in/out of an electric wire through an external environment.

However, a wiring physically needs a length to some degree. Moreover, a magnetic flux cannot be perfectly cancelled by using a twisted wire or a parallel plate. For this reason, a large current circuit or a high frequency circuit still has a problem of the wiring parasitic L. In addition, a conventional noise current absorber has a disadvantage in that the problem of the wiring parasitic L cannot be solved sufficiently.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a wiring core structure capable of suppressing a wiring parasitic L (inductance) more effectively, and a semiconductor evaluation device and a semiconductor device which use the wiring core structure.

The wiring core structure according to the present invention includes a tubular-shaped core portion and a wound wire. The core portion includes a wiring hole for passage of a main wire to be a parasitic-inductance suppression target and has a body portion made of a soft magnetic material. The wound wire is formed by winding the wire around the core portion and has both ends short-circuited.

The core portion includes a plurality of divided core portions which are disposed in a superposed relation and each have a wiring hole. The divided core portions are formed such that shapes of the wiring holes and outside diameters of body portions are different from each other. Consequently, there is implemented a superposition structure without overlapping in plan view.

The wiring core structure according to the present invention produces an inductance suppression effect for reducing a parasitic inductance of a main wire by utilizing the principle of a transformer in which a main wire is set to be a primary cable and a wound wire is set to be a secondary cable in the case where a current flows to the main wire.

In this case, in the plurality of divided core portions, the shapes (diameters or the like) of the wiring holes, and the outer diameters (diameters of outermost peripheral portions) of body portions are made different from each other. Thus, by changing a combination of superposition structures between the plurality of divided core portions depending on a thickness of the main wire, it is possible to efficiently decrease a magnetic flux to be generated around the main wire.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

<Principle of the Invention>

The present invention utilizes a characteristic of a transformer. First of all, the characteristic of the transformer will be described.FIG. 1is an explanatory view showing a configuration of a general transformer andFIG. 2is a circuit diagram showing an equivalent circuit of the transformer shown inFIG. 1.

As shown in these drawings, a primary voltage V1and a secondary voltage V2are obtained from a primary input terminal (a left side in the drawing) and a secondary output terminal (a right side in the drawing). In these drawings, a ratio of a mutual conductance M to the numbers of turns of inductances L1and L2are set to be 1 to N between a primary current I1and an inductance L1at a primary side and a secondary current I2and an inductance L2at a secondary side.

The primary voltage V1and the secondary voltage V2are expressed by the following equations (1) and (2).
[Equation 1]
V1=L1·dI1/dt+M·dI2/dt(1)
[Equation 2]
V2=M·dI1/dt+L2·dI2/dt(2)

Moreover, a relationship between the primary voltage V1and the secondary voltage V2is derived from the following equations (3) and (4).
[Equation 3]
L1·L2=M2(3)
[Equation 4]
V1−L1·dI1/dt+M·dI2/dt=L1/M(M·dI1/dt+L2·dI2/dt)=L1/M×V2  (4)

If the secondary output terminal is short-circuited, the secondary voltage is V2=0V so that V1=0V is obtained.

On the other hand, energy PM to be stored in the transformer is expressed by {PM−V1·I1+V2·I2}. When the secondary side is short-circuited, {V1=V2=0V} is set so that {PM=0 W} is obtained. In other words, it means that the energy is not stored in the transformer when the secondary side is short-circuited.

In the meantime, energy of a magnetic field per unit volume is proportional to a square of a magnetic flux density. Accordingly, the energy to be stored in the transformer is 0 W so that a magnetic flux generated in a core is also 0 Wb.

Thus, when a secondary output of the transformer is short-circuited, the secondary current I2flows to cancel the magnetic flux in the core also in the case where the primary current I1is caused to flow to the primary side. For this reason, the magnetic flux is not generated in the core.

The present invention utilizes the characteristic of the transformer.

FIGS. 3A and 3BandFIG. 4are explanatory views each showing a (wiring) core structure100to be the technical premise according to the present invention. As shown in these drawings, the core structure100is constituted (formed) of a tubular-shaped core portion1including a wiring hole2for passage of a main wire4to be a parasitic-inductance suppression target and a body portion (a substantial part in which the wiring hole2is to be formed) made of a soft magnetic material, and a wound wire3formed by winding the wire around a side surface of the core portion1and having both ends short-circuited. As shown inFIG. 4, the core portion1is disposed such that the main wire4passes through an inner part of the wiring hole2. Thus, the core structure100is used.

With this configuration, when a current is caused to flow to the main wire4serving as a primary cable, a magnetic flux is generated around the main wire4. However, according to the characteristic of the transformer, the current flows through the core portion1so as to cancel the magnetic flux in the wound wire3serving as a secondary cable. For this reason, the magnetic flux is not generated. In other words, the magnetic flux is not generated in the care portion1. Correspondingly, the generation of the magnetic flux is decreased. Thus, a parasitic L resulting from the main wire4is reduced.

Thus, by utilizing the characteristic of the transformer, the parasitic L resulting from the main wire4is reduced in wiring core structures (core structures10,20,30A to30D,40,60A to60C and80) which will be described in the following first to seventh preferred embodiments.

First Preferred Embodiment

FIG. 5is a plan view showing the (wiring) core structure10according to the first preferred embodiment of the present invention. As shown inFIG. 5, a core portion in the core structure10according to the first preferred embodiment is made up of an assembly of a plurality of divided core portions11to13, each of which has a wiring hole. The divided core portions11to13can be superposed on one another and disposed so as not to overlap in plan view.

Each of the divided core portions11to13has a wiring hole2for passage of a main wire4to be a parasitic-inductance suppression target, and has a tubular-shaped (cylindrical) body portion made of a soft magnetic material having a high magnetic permeability, for example, ferrite in the same manner as the core portion1according to the technical premise shown inFIGS. 3A and 3BandFIG. 4. Then, the core structure10is provided with a wound wire3which is formed by winding the wire around each of the divided core portions11to13and has both ends short-circuited.

However, the core structure10according to the first preferred embodiment features that the divided core portions11to13are formed such that inside diameters (diameters of wiring holes defining shapes of the wiring holes) and outside diameters of the body portions (diameters of outermost peripheral parts) are different from each other. More specifically, the divided core portion11has the diameter of the wiring hole2which is the largest and is slightly larger than the outside diameter of the body portion of the divided core portion12, and the divided core portion12has the diameter of the wiring hole2which is large and is slightly larger than the outside diameter of the body portion of the divided core portion13. Accordingly, the outside diameter of the body portion is also reduced in order of the divided core portion11, the divided core portion12and the divided core portion13, and the wiring hole2of the divided core portion13is a minimum wiring hole in the core structure10having the smallest diameter.

Accordingly, the core structure10according to the first preferred embodiment has a superposition structure without overlapping in plan view in which the divided core portion12can be disposed in the wiring hole2of the divided core portion11and the divided core portion13can be disposed in the wiring hole2of the divided core portion12.

In general, a magnetic flux generated around a main circuit increases in density in a closer place to a wire and decreases in density with the distance from the wire. Thus, in order to reduce a parasitic L resulting from the main wire4, it is necessary to decrease the magnetic flux to be generated in the vicinity of the main wire4as greatly as possible. With the core structure10according to the first preferred embodiment, if the wiring hole2is large with respect to a cable serving as the main wire4, comparatively large clearance is formed between the main wire4and the core portion so that the magnetic flux cannot be decreased efficiently. Thus, by preparing the divided core portions11to13in which the diameters of the wiring holes2and the outside diameters of the body portions are different from each other and changing the combination of the superposition structures depending on a thickness of the cable serving as the main wire4, it is possible to produce an advantage that the magnetic flux to be generated around the main wire4can be decreased efficiently.

For example, in the case where the thickness of the main wire4is small, all of the divided core portions11to13are used in a superposed relation, and the main wire4is disposed in the wiring hole2of the divided core portion13. In the case where the thickness of the main wire4has a middle degree (is greater than the wiring hole2of the divided core portion13), the two divided core portions11and12except for the divided core portion13are used in a superposed relation, and the main wire4is disposed in the wiring hole2of the divided core portion12. In the case where the thickness of the main wire4is greater than the wiring hole2of the divided core portion12, the divided core portion11is used alone, and the main wire4can be disposed in the wiring hole2of the divided core portion11.

Thus, the core structure10according to the first preferred embodiment has an inductance suppressing effect for reducing the parasitic inductance of the main wire4by utilizing the principle of a transformer in which the main wire4is set to be a primary cable and the wound wire3is set to be a secondary cable in the case where a current flows to the main wire4.

Furthermore, in the core structure10according to the first preferred embodiment, the diameters of the wiring holes and the outside diameters of the body portions are made different from each other in the divided core portions11to13(the plurality of divided core portions). Thus, by changing the combination of the superposition structures depending on the thickness of the main wire4, it is possible to efficiently decrease the magnetic flux to be generated around the main wire.

Second Preferred Embodiment

FIG. 6is an explanatory view showing a (wiring) core structure20according to a second preferred embodiment of the present invention. As shown inFIG. 6, a core portion in the core structure20according to the second preferred embodiment is made up of an assembly of a plurality of divided core portions21to26which are stacked on one another and disposed and each have a wiring hole.

Each of the divided core portions21to26has a wiring hole2for passage of a main wire4to be a parasitic-inductance suppression target and has a body portion made of a soft magnetic material in the same manner as the core portion1according to the technical premise shown inFIGS. 3A and 3BandFIG. 4. Then, the core structure20is provided with a wound wire3which is formed by winding the wire around each of the divided core portions21to26and has both ends short-circuited.

However, with the core structure20according to the second preferred embodiment, the main wire4having a curved (or bent) portion4cpartially is set to be a parasitic-inductance suppression target, and the wiring hole2of the core structure20(the whole divided core portions21to26) is provided for passage of the curved portion4c.

For this reason, each of the divided core portions21to26(particularly, the divided core portions22to25) forming the core portion of the core structure20features to be a deformed and divided core portion having an obliquely sectional shape in which an interval between an upper surface (an upper side in the drawing) and a lower surface (a lower side in the drawing) is monotonously changed between both opposite ends (for example, ends P22aand P22bof the divided core portion22) of the body portion in plan view (as seen in a plane where a circular shape including the wiring hole2is formed). The “obliquely sectional shape” represents such a shape that at least one of the upper surface and the lower surface is a surface obtained by obliquely cutting a cylindrical object (which corresponds to a surface referred to as a “Sogi” of the New Year's decorative pine trees).

FIG. 7is an explanatory view showing a (wiring) core structure300for comparison with the second preferred embodiment. As shown inFIG. 7, a core portion in the core structure300is made up of an assembly of a plurality of divided core portions31to36which are stacked on one another and disposed in a vertical direction, and each have a wiring hole2.

Each of the divided core portions31to36has the wiring hole2for passage of a main wire4to be a parasitic-inductance suppression target, and has a body portion made of a soft magnetic material and formed into a tubular shape in the same manner as the core portion1according to the technical premise shown inFIGS. 3A and 3BandFIG. 4. Then, the core structure300is provided with a wound wire3which is formed by winding the wire around a side surface of each of the divided core portions31to36and has both ends short-circuited.

In the case of the stacking structure of the tubular-shaped divided core portions31to36as in the core structure300shown inFIG. 7, comparatively large clearance is formed among the divided core portions31to36when they are disposed corresponding to the curved portion4cof the main wire4shown inFIG. 6. In the clearance part, a magnetic flux is not cancelled but left.

On the other hand, in the core structure20according to the second preferred embodiment, each of the divided core portions21to26is formed into an obliquely sectional shape. Consequently, corresponding to a bent state of a cable serving as the main wire4, a whole or part of the divided core portions21to26can be disposed in combination such that clearance is not formed as much as possible.

Thus, at least one of the divided core portions21to26(the plurality of divided core portions) includes a deformed and divided core portion having an obliquely sectional shape. Consequently, it is possible to reduce the interval among the divided core portions21to26with respect to the curved portion4cof the main wire4. Accordingly, it is possible to produce an effect for enhancing an inductance suppressing effect more greatly.

Third Preferred Embodiment

FIG. 8is an explanatory view showing a (wiring) core structure30A according to a first mode of a third preferred embodiment of the present invention. As shown inFIG. 8, a core portion in the core structure30A according to the third preferred embodiment is a tubular-shaped core portion made up of a core assembly3X of a plurality of divided core portions3ieach of which is a plate-shaped core. The divided core portions3iare stacked and disposed without clearance between the respective divided core portions in a vertical direction, each have a wiring hole2, and are made of a soft magnetic material having a high magnetic permeability, for example, ferrite. The respective divided core portions3ihave planar shapes (shapes of the wiring holes2and outside diameters of body portions) set to be identical.

In the same manner as the core structure300shown inFIG. 7, each of the divided core portions3ihas the wiring hole2for passage of a main wire4to be a parasitic-inductance suppression target and has the body portion made of a soft magnetic material. Then, the core structure30A is provided with a wound wire3which is formed by winding the wire around the core assembly3X and has both ends short-circuited.

The divided core portion3iin the core structure30A according to the third preferred embodiment has an outer-peripheral space part, provided in the body portion (a substantial part around the wiring hole2), for inserting the main wire4into the wiring hole2at a side-surface side of the body portion (a space for forming an air gap16), and a through hole17, provided on the body portion, for causing a common coupling pin18to penetrate between the divided core portions3iof the core assembly3X.

In the core structure30A, the coupling pin18is inserted into the through hole17provided on the core assembly3X so that the plurality of divided core portions3iare integrated as the core assembly3X in a coupling pin insertion state. Then, the core assembly3X is fixed. The fixation of the core assembly3X is carried out by using a method such as calking or bonding.

Thereafter, it is possible to short-circuit both ends by the wound wire3wound around the core assembly3X as described above.

On the other hand, in the coupling pin insertion state, the outer-peripheral space parts of the divided core portions3iof the core assembly3X are disposed so as to overlap (coincide) in plan view. Consequently, an air gap16(a side-surface space region defined by an assembly of the outer-peripheral space parts) is formed in a part of the side surface of the core assembly3X to be the core portion.

Before formation of a covering member19A, the main wire4is caused to pass through the air gap16so that the main wire4is disposed in the wiring hole2of the core assembly3X, and then, the covering member19A serving as a closing member for closing the air gap16is provided on the outer peripheral surface side of the core assembly3X including the air gap16. The covering member19A is made of a soft magnetic material having a high magnetic permeability. Although the covering member19A is fixed by methods such as fitting and screwing, the present invention is not restricted to these fixing methods. Moreover, a sheet-like magnetic shielding material may be stuck as the covering member19A.

The covering member19A implements a closing structure that prevents the main wire4inserted into the wiring hole2from being removed toward the outside of the wiring hole2through the air gap16.

Thus, with the core structure30A according to the first mode of the third preferred embodiment, in a previous stage to the formation of the covering member19A, the core assembly3X (the plurality of divided core portions3i) is disposed to have an opening structure in which the main wire4can be inserted into the wiring hole2through the air gap16defined by the assembly of the outer-peripheral space parts of the body portions of the respective divided core portions3i, and the main wire4is inserted into the wiring hole2through the air gap16. Consequently, the main wire4can be disposed in the wiring hole2comparatively easily.

The core structure30A can exhibit the inductance suppressing effect for the main wire4with high stability by the closing of the air gap16using the covering member19A.

Thus, after the main wire4is disposed in the wiring hole2with respect to the core assembly3X in the coupling pin insertion state, the covering member19A serving as a closing member is provided. Consequently, in the coupling pin insertion state, the core assembly3X can be changed from the opening state having the air gap16to the closing state.

For example, in the case where the core structure300shown inFIG. 7is utilized for the main wire4which has already been connected to a device, it is necessary to once detach one of ends of the main wire4from the device, and to then insert the end into the wiring hole2of the core structure300. Consequently, workability is poor.

On the other hand, in the core structure30A according to the third preferred embodiment, the main wire4serving as a primary cable is inserted through the air gap16into the wiring hole2before the formation of the covering member19A, and then the covering member19A can be provided. Thus, it is possible to considerably improve workability in the case where the core structure30A is formed and used.

Furthermore, according to the first mode of the third preferred embodiment, the covering member19A can prevent the magnetic flux generated from the main wire4from leaking to the outside of the core structure30A.

FIG. 9is an explanatory view showing a structure of a (wiring) core structure30B according to a second mode of the third preferred embodiment of the present invention. The core structure30B shown inFIG. 9is implemented in the following manner: a main wire4is passed through an air gap16and is thus disposed in the main wire4in a wiring hole2of a core assembly3X before formation of a covering member19B serving as a closing member for closing the air gap16, and then the covering member19B is provided on an inner peripheral surface side of the core assembly3X including the air gap16. Since the other configurations, an inductance suppressing effect, a workability improving effect and the like are the same as those in the core structure30A according to the first mode shown inFIG. 8, description thereof will be omitted.

According to the second mode of the third preferred embodiment, the covering member19B can prevent a magnetic flux (a noise) generated on the outside from leaking into a core portion (a wiring hole).

FIG. 10is an explanatory view showing a structure of a (wiring) core structure30C according to a third mode of the third preferred embodiment of the present invention. In the core structure30C shown inFIG. 10, a main wire4is passed through an air gap16and is thus disposed in the main wire4in a wiring hole2of a core assembly3X before formation of a covering member19C, and then a covering member19A and a covering member19B, which each serve as a closing member for closing the air gap16, are respectively provided on outer and inner peripheral surface sides of the core assembly3X including the air gap16. Since the other configurations, an inductance suppression effect, a workability improving effect and the like are the same as those in the core structure30A shown inFIG. 8, description thereof will be omitted.

According to the third mode of the third preferred embodiment, the covering members19A and19B can prevent a magnetic flux generated from the main wire4from leaking to the outside of the core structure30C.

Fourth Preferred Embodiment

FIG. 11is an explanatory view showing a (wiring) core structure30D according to a fourth preferred embodiment of the present invention. As shown inFIG. 11, a core portion in the core structure30D according to the fourth preferred embodiment is a tubular-shaped core portion is made up of a core assembly3X of a plurality of divided core portions3ieach of which is a plate-shaped core. The divided core portions3iare stacked and disposed without clearance between the respective divided core portions in a vertical direction, each have a wiring hole2, and are made of a soft magnetic material having a high magnetic permeability, for example, ferrite. The respective divided core portions3ihave planar shapes (diameters of the wiring holes2and outside diameters of body portions) set to be identical.

Since a wound wire3, an air gap16(not shown inFIG. 11), a through hole17, a coupling pin18and the like are the same as those of the first to third modes of the third preferred embodiment shown inFIGS. 8 to 10, description thereof will be omitted.

In a coupling pin insertion state, outer-peripheral space parts of the respective divided core portions3iin the core assembly3X are disposed so as to overlap in plan view. Thus, the air gap16to be a side-surface space region (an assembly of the outer-peripheral space parts) is formed on a part of a side surface of the core assembly3X forming the core portion.

First of all, a main wire4is passed through the air gap16and is thus disposed in the wiring hole2of the core assembly3X before formation of a cap portion50, and then the cap portion50to be a click portion is fitted in the air gap16of the core assembly3X. Consequently, the core structure30D is formed. The cap portion50is constituted of a body portion51and a soft-magnetic-material surface portion52. The body portion51has flexibility and is formed into such a shape as to conform to the air gap16. For example, in the case where the air gap16is formed into a trapezoidal shape in plan view, in which an inside (the wiring hole2side) is set to be a short side, the body portion51is also formed into a trapezoidal shape in plan view, in which an inside is set to be a short side.

Furthermore, the cap portion50(the body portion51) has flexibility. Thus, the cap portion50fitted in the air gap16can be removed comparatively easily. In other words, the cap portion50can be removable from the air gap16.

For example, in the case where the core structure300shown inFIG. 7is utilized for the main wire4which has already been connected to a device, it is necessary to once detach one of ends of the main wire4from the device, and to then insert the end into the wiring hole2of the core structure300. Consequently, workability is poor.

On the other hand, in the core structure30D according to the fourth preferred embodiment, the main wire4serving as a primary cable is inserted through the air gap16into the wiring hole2before the formation of the cap portion50, and then the cap portion50for closing the air gap16can be provided. Thus, it is possible to considerably improve workability when the core structure30D is formed and used.

The soft-magnetic-material surface portion52made of a soft magnetic material having a high magnetic permeability is formed on a surface of the cap portion50along an outer peripheral surface of the core structure30D. Although the body portion51is desirably made of a flexible material, and may be obtained by bending a metal plate or may be made of a resin material, the present invention is not restricted thereto.

The cap portion50serving as the closing member for closing the air gap16implements a closing structure that prevents the main wire4inserted in the wiring hole2from being removed toward the outside of the wiring hole2through the air gap16.

Thus, with the core structure30D according to the fourth preferred embodiment, in a previous stage to the formation of the cap portion50, the core assembly3X (the plurality of divided core portions3i) is disposed to have an opening structure in which the main wire4can be inserted into the wiring hole2through the air gap16defined by the assembly of the outer-peripheral space parts of the body portions of the respective divided core portions3i, and the main wire4is inserted into the wiring hole2through the air gap16. Consequently, the main wire4can be disposed in the wiring hole2comparatively easily.

The cap portion50is fitted in the air gap16so that the structure of the core assembly3X is set into the closing structure. Consequently, it is possible to exhibit the inductance suppression effect for the main wire4with high stability.

Moreover, after the main wire4is disposed in the wiring hole2with respect to the core assembly3X in the coupling pin insertion state, the cap portion50serving as a closing member is fitted in the air gap16. Consequently, the core assembly3X can be changed comparatively easily from the opening structure having the air gap16to the closing structure. For this reason, it is possible to produce the same workability improving effect as that in the third preferred embodiment.

Furthermore, the cap portion50according to the fourth preferred embodiment can be removable from the air gap16. Correspondingly, it is possible to enhance the workability more greatly than in the third preferred embodiment. Depending on the presence of attachment of the cap portion50(the click portion) having the flexibility, it is possible to set the closing structure/opening structure in the core assembly3X comparatively easily.

Furthermore, according to the fourth preferred embodiment, the cap portion50can prevent a magnetic flux generated from the main wire4from leaking to the outside of the core structure30D.

Fifth Preferred Embodiment

FIGS. 12 and 13are explanatory views each showing a (wiring) core structure40according to a first mode of a fifth preferred embodiment of the present invention, andFIG. 12is a perspective view showing the whole core structure40andFIG. 13is a perspective view showing a planar structure of a divided core portion4i(i=1 to 3). Herein,FIG. 13shows an XY rectangular coordinate system.

As shown in these drawings, a core portion in the core structure40according to the fifth preferred embodiment is a tubular-shaped core portion obtained by stacking divided core portions41to43each of which is a plate-shaped core. The divided core portions41to43are stacked and disposed without clearance between the respective divided core portions in a vertical direction (a Z direction), each have a wiring hole2, and are made of a soft magnetic material having a high magnetic permeability, for example, ferrite. The respective divided core portions41to43have planar shapes (sizes of the wiring holes2and outside diameters of body portions) set to be identical.

Each of the divided core portions41to43has the wiring hole2for passage of a main wire4to be a parasitic-inductance suppression target and has a body portion made of a soft magnetic material in the same manner as in the core structure300shown inFIG. 7. Then, the core structure40is provided with a wound wire3which is formed by winding the wire around the core portion (an assembly of the divided core portions41to43) and has both ends short-circuited.

The divided core portions41to43in the core structure40according to the fifth preferred embodiment have outer-peripheral space parts161to163, provided in the body portion (a substantial part around the wiring hole2), for inserting the main wire4into the wiring hole2at a side-surface side of the body portion, and a plurality of (three in the present preferred embodiment) through holes17, provided in the body portion, for causing a common coupling pin18(not shown) to penetrate through the divided core portions41to43.

In the core structure40, the divided core portions41to43are stacked and disposed temporarily in such a manner that the outer-peripheral space parts161to163overlap one another in plan view. Consequently, the main wire4can be inserted into the wiring hole2through an air gap16(seeFIGS. 8 to 10) formed on the side surface of the core portion by the outer-peripheral space parts161to163.

Moreover, as shown inFIG. 13, the respective divided core portions4i(i=1 to 3) have a counterbore portion46which is recessed from a surface in a circumferential direction of the body portion (the substantial part on the outer periphery of the wiring hole2), and is provided with the three through holes17in a part thereof. When forming an arrangement structure of the outer-peripheral space part in the divided core portion in the following description, it is possible to recognize a position of the through hole17comparatively easily by using the counterbore portion46as a guide.

As shown inFIG. 12, in the coupling pin insertion state in which three coupling pins18are inserted into the three through holes17among the divided core portions41to43, it is possible to implement a closing structure in which the main wire4inserted in the wiring hole2is not removed from the wiring hole2to the outside by the arrangement structure of the divided core portions41to43in which the outer-peripheral space parts161to163of all the divided core portions41to43do not overlap one another in plan view.

Herein, the closing structure is implemented by the arrangement structure of the divided core portions41to43in which at least two outer-peripheral space parts16i(i=1 to 3) in the divided core portions41to43do not overlap each other in plan view in an XY plane ofFIG. 13in the coupling pin insertion state.

After the closing structure is implemented, both ends are short-circuited by the wound wire3wound around the core portion constituted of the divided core portions41to43. Consequently, the core structure40according to the fifth preferred embodiment is formed and used.

Thus, in the core structure40according to the fifth preferred embodiment, the divided core portions41to43are disposed temporarily in an opening structure in which the main wire4can be inserted into the wiring hole2through the air gap16defined by the assembly of the outer-peripheral space parts161to163of the divided core portions41to43and the main wire4is inserted through the air gap16into the wiring hole2in a previous stage to the coupling pin insertion. Consequently, the main wire4can be disposed in the wiring hole2comparatively easily.

After the insertion of the main wire4, the counterbore portion46is used as a guide to recognize the position of the through hole17, and the three coupling pins18are inserted into the three through holes17to fix the divided core portions41to43, thereby implementing the closing structure. Thus, it is possible to exhibit the inductance suppression effect for the main wire4with high stability.

Furthermore, in the core structure40according to the first mode of the fifth preferred embodiment, it is possible to recognize the position of the through hole17by using the counterbore portion46as the guide in each of the divided core portions41to43. Thus, it is possible to change the arrangement of the divided core portions41to43from the opening structure to the closing structure comparatively easily. As a result, it is possible to simplify a work process.

Moreover, according to the fifth preferred embodiment, it is possible to prevent leakage of a magnetic flux generated from the main wire4to the outside and a phenomenon in which a route of a magnetic flux generated in a core assembly3X is divided between the plurality of divided core portions4iby the arrangement structures of the divided core portions41to43.

Moreover, according to the first mode of the fifth preferred embodiment, it is not necessary to attach the covering members19A and19B or the cap portion50unlike the third and fourth preferred embodiments. Correspondingly, it is possible to reduce a cost.

FIGS. 14 and 15are explanatory views each showing a divided core portion4j(j=1 to 3) in a core structure40according to a second mode of the fifth preferred embodiment of the present invention, andFIG. 14is a plan view showing a planar structure of the divided core portion4jandFIG. 15is a cross-sectional view taken along line A-A inFIG. 14. Herein,FIG. 14shows an XY rectangular coordinate system andFIG. 15shows an XZ rectangular coordinate system.

As shown inFIG. 14, the divided core portion4jhas an outer-peripheral space part16j, provided in a body portion (a substantial portion around a wiring hole2), for inserting a main wire4into the wiring hole2at a side-surface side of the body portion, and three through holes17and three recessed portions47(recessed surface-positioning portions) which are provided in the body portion and which cause a common coupling pin18(not shown) to penetrate through the divided core portions41to43. Furthermore, the divided core portion4jis provided with a projected portion48(a projected back-surface-positioning portion) at a back side corresponding to the recessed portion47(XY coordinates are coincident with each other) as shown inFIG. 15. The other configurations are the same as those in the first mode shown inFIGS. 12 and 13except that the counterbore portion46is not provided. Differences from the first mode will be mainly described below.

In the second mode, after the main wire4is inserted, three projected portions48of an upper divided core portion4k(k=1, 2) are fitted in three recessed portions47of a lower divided core portion4(k+1) in each of a pair of divided core portions (divided core portions41and42and divided core portions42and43) which are adjacent in a vertical direction (a Z direction) in the divided core portions41to43. Consequently, it is possible to position the divided core portions41to43.

After the positioning, the three coupling pins18are inserted into the three through holes17to fix the divided core portions41to43. Consequently, it is possible to exhibit the inductance suppression effect for the main wire4with high stability.

Thus, according to the second mode of the fifth preferred embodiment, the projected portions48of the upper divided core portion4kare fitted in the recessed portions47of the lower divided core portion4(k+1) in each of the divided core portions41to43. Consequently, it is possible to change the arrangement of the divided core portions41to43from an opening structure to a closing structure comparatively easily.

In other words, the recessed portion47and the projected portion48serve as positioning guides in stacking the divided core portions41to43. The provision of the recessed portion47and the projected portion48facilitates a work process. Moreover, the recessed portion47and the projected portion48are also used as positioning guides in shifting the positions of the outer-peripheral space parts161to163from the opening structure of the divided core portions41to43. For example, in the case where a silicon steel sheet is used for the body portion of the core portion, it is possible to easily make the recessed portion47and the projected portion48using sheet metal working. Thus, it is also possible to produce an advantage that the recessed portion47and the projected portion48can be provided at a lower cost than the fabrication of the counterbore portion46according to the first mode.

An upper surface of the divided core portion41and a lower surface of the divided core portion43do not need fitting. For this reason, the formation of both the recessed portion47of the divided core portion41and the projected portion48of the divided core portion43may be omitted.

Sixth Preferred Embodiment

FIGS. 16 to 18are explanatory views each showing a (wiring) core structure60A according to a first mode of a sixth preferred embodiment of the present invention, andFIG. 16is a view showing a structure of a side surface of the core structure60A in a state of being attached to (wound around) a main wire,FIG. 17is a plan view showing a planar structure of the core structure60A andFIG. 18is an explanatory view showing a configuration of a core portion61.FIGS. 16 and 18show an XZ rectangular coordinate system andFIG. 17shows an XY rectangular coordinate system.

As shown in these drawings, the core portion61and a wound wire63are provided. The core portion61has flexibility and includes at least a part (a laminated portion61b) made of a soft magnetic material. The wound wire63is provided on an outer peripheral part of the core portion61and has both ends short-circuited. The core portion61having the wound wire63wound directly plural times is provided on an outer peripheral part of a main wire64to be a parasitic-inductance suppression target. Thus, the core structure60A is obtained.

As shown inFIG. 18, the core portion61is constituted of a winding core portion61amade of polyimide having an insulation property and flexibility, and the laminated portion61bobtained by laminating a plurality of core forming layers (core base materials), each of which is made of a soft magnetic material having the flexibility. It is possible to suppress magnetic saturation by laminating the core forming layers.

As shown inFIG. 17, the core portion61is directly wound around the outer periphery of the main wire64plural times and is thus provided in an outer peripheral part of the main wire64. In this case, the core portion61is wound in such a manner that the winding core portion61ais disposed on an inside (a main wire64side) and the laminated portion61bis disposed on the outside (an outer peripheral side).

Furthermore, the core portion61has a core extended portion65fixed to the main wire64side by bending so as to be positioned between an end in an outermost peripheral part of the core portion61and an innermost forming part of the core portion61provided on an outer peripheral surface of the main wire64and in the innermost part. The core extended portion65can also be implemented by extending the laminated portion61bfrom an end of the winding core portion61a, for example.

Thus, the core structure60A can exhibit the inductance suppression effect by a comparatively easy attachment work in which the core portion61having the wound wire63wound therearound covers the outer periphery of the main wire64to be a parasitic-inductance suppression target.

Further, in the core portion61, the laminated portion61bmade of a soft magnetic material can prevent leakage of a magnetic flux generated from the main wire64to the outside of the core structure60A and leakage of a magnetic flux generated on the outside into an inside (the main wire side) of the core portion61.

In addition, the core portion61is reinforced with the winding core portion61ahaving an insulating property. Consequently, damage can be suppressed, and furthermore, an insulating property from the main wire64can be ensured.

Moreover, the core portion61has the winding core portion61adisposed on the main wire64side and wound around the main wire64. Consequently, it is possible to ensure an insulation state between the main wire64and the core portion61.

The winding core portion61ais made of polyimide. Consequently, it is possible to implement the winding core portion61awhich is excellent in flexibility and the insulating property.

Moreover, the core portion61of the core structure60A is formed by covering the outer periphery of the main wire64plural times. Thus, it is possible to effectively suppress a phenomenon in which the core portion causes magnetic saturation.

Furthermore, after the main wire64is disposed, the core portion61is wound around the main wire64in close contact therewith. Consequently, the core structure60A can be disposed in a desirable position comparatively easily.

For example, in the case where a bulk-shaped parasitic inductance suppressing core is utilized for the main wire64which has already been connected to a device, it is necessary to once remove one of ends of a cable serving as the main wire64from the device, and to insert the end through the bulk-shaped core. For this reason, workability is poor.

On the other hand, in the case where the core structure60A is used, the core portion61made of a soft magnetic material having flexibility is wound around the main wire64to be a primary cable and is thus attached thereto, and a distal end is processed (the core extended portion65is bent or a covering member66according to a second mode which will be described below is formed). Consequently, the workability can be improved remarkably.

Furthermore, the core extended portion65is fixed by an inner peripheral part of the core portion61, thereby preventing clearance from being generated on an outermost peripheral tip part of the core portion61. Consequently, it is possible to prevent division of a route of a magnetic flux generated in the core portion61.

FIG. 19is a plan view showing a (wiring) core structure60B according to a second mode of the sixth preferred embodiment of the present invention. As shown inFIG. 19, the core structure60B features that a covering member66made of a soft magnetic material having a high magnetic permeability is formed by covering an end of an outermost peripheral part in a core portion61(a laminated portion61b) and a periphery thereof in place of the core extended portion65. Since the other structures are the same as those in the first mode shown inFIGS. 16 to 18, description thereof will be omitted.

The core structure60B is provided with the covering member66to reliably prevent clearance from being generated on a tip of the outermost peripheral part in the core portion61. Consequently, it is possible to prevent leakage of a magnetic flux to the outside, thereby hindering a route of a magnetic flux generated in the core portion61from being divided.

The covering member66is fixed by a method such as bonding. However, the present invention is not restricted to these techniques. A sheet-like magnetic shield material may be stuck as the covering member66or wound around the whole outer peripheral part of the core portion61.

Also in the second mode, the core extended portion65may further be provided to enhance an effect for preventing leakage of a magnetic flux to the outside and division of a magnetic flux route still more in the same manner as in the first mode.

FIG. 20is a plan view showing a planar structure of a (wiring) core structure60C according to a third mode of the sixth preferred embodiment of the present invention. As shown inFIG. 20, a core portion61is wound around a main wire64with a space region69provided between the core portion61and the main wire64. The other configurations are the same as those in the first mode shown inFIGS. 16 to 18.

In the core structure60C according to the third mode, the space region69is ensured between the core portion61and the main wire64. Thus, it is possible to produce an advantage that a movement thereof can be carried out comparatively easily after attachment of the core structure60C.

Although the core portion61is constituted of the winding core portion61aand the laminated portion61bin the first to third modes of the sixth preferred embodiment shown inFIGS. 16 to 20, the core portion61may be constituted of only the laminated portion61b.

Seventh Preferred Embodiment

FIGS. 21 and 22are explanatory views each showing a (wiring) core structure80according to a seventh preferred embodiment of the present invention.FIG. 21is a perspective view showing a bobbin67in a core structure80andFIG. 22is a perspective view showing the whole configuration of the core structure80.FIGS. 21 and 22show an XYZ rectangular coordinate system.

As shown inFIG. 21, the bobbin67is constituted of a hollow portion67aand a body portion67b, a core portion61can be inserted into the hollow portion67a, and a wound wire63is wound around an outer periphery of the body portion67bhaving flexibility and made of an insulating material.

As shown inFIG. 22, the core portion61is inserted into the hollow portion67aof the bobbin67, thereby forming the core structure80. In the core structure80, the core portion61including the bobbin67is bent and wound directly around an outer periphery of a main wire64plural times. Thus, the outer periphery of the main wire64can be covered. As a mode for providing the core portion61on the outer peripheral part of the main wire64, it is also possible to use any of the first to third modes according to the sixth preferred embodiment.

Thus, the core structure80according to the seventh preferred embodiment is different from that in the sixth preferred embodiment in that the wound wire63is not directly wound around the core portion61but the wound wire63is wound around the bobbin67made of the insulating material and the core portion61and the bobbin67are integrated with each other. In other words, the wound wire63is indirectly provided on the outer peripheral part of the core portion61by way of the bobbin67.

In respect of a process, it is not easy to wind a cable serving as the wound wire63while holding the core portion61made of a material having flexibility, thereby forming a dense and stable coil in a predetermined direction. Thus, as in the seventh preferred embodiment, the wound wire63is wound around the bobbin67and then the core structure80including the bobbin67and the core portion61is disposed with respect to the main wire64.

Thus, with the core structure80according to the seventh preferred embodiment, the bobbin67is used for winding the wound wire63. Consequently, it is possible to produce an advantage that the wound wire63can be disposed on the core portion61comparatively easily.

In addition, with the core structure80according to the seventh preferred embodiment, the placement can easily be carried out, and furthermore, the wound wire63can readily be changed and attached/removed over the bobbin67when the winding number of the wound wire63is to be varied. Although the body portion67bof the bobbin67is desirably made of engineering plastic which is excellent in environment resistance, the present invention is not restricted thereto.

Eighth Preferred Embodiment

FIG. 23is a circuit diagram showing a circuit configuration of a semiconductor evaluation device according to an eighth preferred embodiment of the present invention. As shown inFIG. 23, a switching characteristic evaluation circuit90is constituted of a diode D1, an L load portion LD, a power supply VD and a capacitor C10, and one of electrodes of a capacitor C10, a cathode of the diode D1, and one of ends of the L load portion LD are connected to a positive electrode of the power supply VD. A collector of an IGBT8(measurement target element) to be a switching element of a switch characteristic evaluation target is connected to an anode of the diode D1and the other end of the L load portion LD. An emitter of the IGBT8and the other electrode of the capacitor C10are grounded.

The switching characteristic evaluation circuit90thus configured has a measuring function capable of evaluating a switching characteristic of the IGBT8(particularly, in an OFF state) by measuring a current flowing to the IGBT8through the L load portion LD.

When exhibiting the measuring function, the switching characteristic evaluation circuit90sets, as a core structure arrangement region A1, a wiring region between the positive electrode of the power supply VD and one of the ends of the L load portion LD; as a core structure arrangement region A2, a wiring region between one of the ends of the L load portion LD and the anode of the diode D1; as a core structure arrangement region A3, a wiring region between the other end of the L load portion LD and the cathode of the diode D1; and as a core structure arrangement region A4, a wiring region (a wiring portion of the measurement target element) between the emitter of the IGBT8and the ground.

The switching characteristic evaluation circuit90sets a wiring portion in at least one of the core structure arrangement regions A1to A4as a main wire4(64) and places any of the wiring core structures according to the first to seventh preferred embodiments, thereby enhancing the inductance suppression effect. Thus, it is possible to measure the switching characteristic (an operating characteristic) of the IGBT8with high precision.

Furthermore, by reducing a parasitic L of the wiring portion provided with the wiring core structure, it is possible to lessen an induced current flowing to the other part by inductive coupling to the parasitic L of the wiring portion. As a result, it is possible to realize energy saving of the switching characteristic evaluation circuit90.

In addition, the parasitic L of the wiring portion provided with the wiring core structure is reduced to decrease a surge voltage so that a device is prevented from being destroyed by the surge voltage. Consequently, it is possible to enhance a yield of the switching characteristic evaluation circuit90.

Ninth Preferred Embodiment

FIGS. 24A and 24Bare explanatory diagrams showing an IGBT module70according to a ninth preferred embodiment of the present invention, andFIG. 24Ashows a circuit configuration of the IGBT module70andFIG. 24Bshows a device structure of the IGBT module70.

As shown inFIG. 24A, diodes D11and D12are connected in parallel with IGBTs81and82with an emitter side set to be an anode. An emitter of the IGBT81(an anode of the diode D11) and a collector of the IGBT82(a cathode of the diode D12) are electrically connected to each other.

The IGBT81has a collector electrode P11(C1), an emitter electrode P12(E1) and a gate electrode P13(G1). Similarly, the IGBT82has a collector electrode P21(C2E1), an emitter electrode P22(P22a, P22b) (E2) and a gate electrode P23(G2).

In the circuit shown inFIG. 24A, a wiring region between the collector electrode P11and an internal collector electrode portion P25(in the vicinity of a cathode connection point of the diode D11) is set as a core structure arrangement region A11, a wiring region between the emitter of the IGBT81and the collector of the IGBT82is set as a core structure arrangement region A12, a wiring region between the collector electrode P21and an internal collector electrode portion P26of the IGBT82is set as a core structure arrangement region A13, and a wiring region between the emitter electrode P22aand the emitter electrode P22bof the IGBT82is set as a core structure arrangement region A14.

On the other hand, as shown inFIG. 24B, the IGBT module70is configured to accommodate a plurality of silicon chips77disposed on a metal pattern (not shown) of a surface of an insulating (ceramic) substrate76through the insulating substrate76on a copper base plate75in a silicone gel portion72and a (epoxy) resin sealing portion73in a case71. The silicon chips77or the silicon chip77and a metal pattern are connected electrically by an aluminum wire78.

In addition, inFIG. 24B, the collector electrode P21, the emitter electrode P22aand the collector electrode P11, and an auxiliary terminal P30are provided as an external connecting electrode of the IGBT module70in an upper part of the case71. The collector electrode portion P26and the emitter electrode P22bin the IGBT82and the emitter electrode P12and the collector electrode portion P25in the IGBT81are provided as electrodes (portions) having bent parts on the corresponding silicon chips77. With the configurations, the circuit shown inFIG. 24Ais implemented.

Accordingly, in the IGBT module70, the wiring portions of the collector electrode portion P26, the emitter electrode P22b, the emitter electrode P12and the collector electrode portion P25included in the core structure arrangement regions A13, A14, A12and A11shown inFIG. 24Bare set as a main wire4(a main wire64), and any of the wiring core structures described in the first to seventh preferred embodiments is provided to enhance an inductance suppression effect. Consequently, an operating characteristic can be enhanced.

Furthermore, by reducing a parasitic L of the wiring portion provided with the wiring core structure, it is possible to lessen an induced current flowing to the other part by inductive coupling to the parasitic L of the wiring portion. As a result, it is possible to realize energy saving of the IGBT module70.

In addition, the parasitic L of the wiring portion provided with the wiring core structure is reduced to decrease a surge voltage so that a device is prevented from being destroyed by the surge voltage. Consequently, it is possible to enhance a yield of the IGBT module70.