JP2000091142A - Magnetic component with leads and noise reducing circuit using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve surface mountability by providing a hollow part for inserting leads in a soft magnetic material and an insulating case, and inserting the leads made of a plurality of conductors into the part. SOLUTION: A hollow part for inserting leads is provided at a soft magnetic material and an insulating case 3, and leads made of a plurality of two or more conductors are inserted into the part. Insulating layers for interlayer insulating the conductors are alternately aligned as the leads made of the plurality of the conductors. As a lead shape, a rectangular section is preferable, and the conductors and insulating resins are alternately aligned, further covered with an insulating resin, and integrated. In this case, the section of the lead and the section of the hollow part of the case are formed in the same shape. As the shape of the case 3, a rectangular parallelepiped shape is desired. A length of the case 3 in a heightwise direction is preferably shorter than lateral and longitudinal lengths.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic component having leads and a noise reduction circuit using the same, and more particularly to a magnetic component effective for reducing noise of a switching power supply such as a semiconductor element of a DC-DC converter. More specifically, the present invention relates to a noise reduction circuit that improves surface mountability by improving the shape of a lead or an insulating case, and improves the connection method of a lead, thereby enabling various uses to be properly used.

[0002]

2. Description of the Related Art A semiconductor device such as a diode or a transistor can be cited as a noise source in an electronic circuit such as a switching power supply.
(Referred to as a noise reduction element). The noise reduction element is formed by a cylindrical body (a toroidal magnetic core) made of various magnetic materials such as an amorphous alloy and an insulating member disposed around the cylindrical body, for example, and is used by inserting leads of a semiconductor element. Is done.

[0003] This method has been widely used in recent years because noise measures can be taken for a power supply unit that has been assembled as compared with a method of reducing noise using a normal noise filter or the like. Further, since the conventional ferrite is changed from a ferrite to a magnetic material having a small loss such as an amorphous alloy, problems such as heat generation and cracking of the noise reduction element are also improved.

[0004]

However, for example, Japanese Unexamined Patent Publication No.
Conventional noise reduction elements such as 71164 and Japanese Patent Application Laid-Open No. 5-234760 use a cylindrical magnetic core that is mainly passed through one lead of a semiconductor element. You could only get one turn for one turn. In order to increase the inductance value, the number of windings must be increased. However, in order to obtain a winding effect of two or more turns, it is necessary to separately wind the cylindrical magnetic core.

In recent years, there has been a strong demand for miniaturization of semiconductor circuits, and there has been a demand for miniaturization of components such as noise reduction elements and surface mounting. Therefore, when the above-mentioned noise reducing element using a wound-type cylindrical magnetic core is surface-mounted, special measures such as soldering a mounting member such as a special pedestal are required because the surface mounting cannot be performed as it is, and the noise reducing element is large-sized. It has been a factor of increasing complexity, complicating work processes, and increasing costs.

In addition, the conventional noise reduction element comprising a cylindrical magnetic core can be used only as a noise reduction element such as a normal mode choke coil, and can be diverted as another component, for example, a common mode choke coil. I was without.

[0007]

According to the present invention, there is provided a magnetic component with a lead according to the first aspect of the present invention, wherein the magnetic component includes a toroidal soft magnetic material housed in an insulating case. A magnetic component with a lead, wherein a hollow portion for inserting a lead is provided in an insulating case, and a lead made of two or more conductors is inserted into the hollow portion.

According to a second aspect of the present invention, there is provided the magnetic component with a lead according to the first aspect, wherein the layers of the respective conductors of the lead are insulated and integrated. According to a third aspect of the present invention, there is provided the magnetic component with a lead according to the first or second aspect, wherein a cross section of the lead is square.

According to a fourth aspect of the present invention, there is provided the magnetic component with a lead according to any one of the first to third aspects, wherein the hollow portion of the insulating case has the same shape as the cross section of the lead. Claim 5
The magnetic component with leads according to any one of claims 1 to 4, wherein the shape of the insulating case is a rectangular parallelepiped.

According to a sixth aspect of the present invention, there is provided the magnetic component with a lead according to any one of the first to fifth aspects, wherein a length in a height direction of the insulating case is smaller than a length in a vertical direction and a horizontal direction.

According to a seventh aspect, the magnetic component with leads according to any one of the first to sixth aspects, wherein the soft magnetic material is an amorphous alloy ribbon. Claim 8 relates to a magnetic component in which a toroidal soft magnetic material is housed in an insulating case, wherein the soft magnetic material and the insulating case are provided with a hollow portion for inserting a lead, and the hollow portion has two or more hollow portions. A noise reduction circuit comprising: mounting a magnetic component with a lead through which a lead made of a conductor is inserted on a circuit board, wherein the conductors are not connected to each other.

According to a ninth aspect of the present invention, there is provided a magnetic component in which a toroidal soft magnetic material is accommodated in an insulating case, wherein the soft magnetic material and the insulating case are provided with a hollow portion for inserting a lead, and the hollow portion has a hollow portion. In a noise reduction circuit in which a magnetic component with leads through which leads made of a plurality of conductors are inserted is attached to a circuit board, an end of one conductor is connected to an opposite end of an adjacent conductor. A noise reduction circuit characterized by the following.

According to a tenth aspect, the noise reduction circuit according to any one of the eighth to ninth aspects, wherein the soft magnetic material is an amorphous alloy ribbon. In the present invention, a toroidal soft magnetic material having a hollow portion is housed in an insulating case, and a plurality of winding effects are obtained by inserting leads made of a plurality of conductors into the hollow portion. It is characterized by.

Further, by controlling the connection method of the leads during surface mounting, it is possible to provide magnetic components with leads, such as a normal mode choke coil and a common mode choke coil, which can be used in various ways.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment for carrying out the present invention will be described. The magnetic component with a lead of the present invention is a magnetic component in which a toroidal soft magnetic material is housed in an insulating case, wherein the soft magnetic material and the insulating case are provided with a hollow portion for inserting a lead, and the hollow portion is provided in the hollow portion. A lead made of two or more conductors is inserted.

First, a lead made of two or more conductors has a structure in which conductors and insulating layers for interlayer insulation are alternately arranged as shown in FIG. As the conductor, an inexpensive conductive material such as Cu or Al is preferable. As the insulating material, there is no particular problem as long as the insulating property can be obtained. However, an organic resin, particularly polyester is preferable from the viewpoint of insulating property and strength.

The lead shape is not particularly limited, but preferably has a rectangular cross section, and a structure in which conductors and insulating resins are alternately arranged is further covered with an insulating resin to be integrated. In this case, it is preferable to integrate the conductors in a state where they are placed in parallel. Further, since it is sufficient that each conductor is interlayer-insulated, conductors coated with insulation may be integrated. When integrated as described above, it becomes easy to insert into a hollow portion of an insulating case described later.

There is no problem if the number of conductors is two or more, and the number of conductors may be increased in order to obtain a desired noise reduction effect. The lead manufactured in this manner is shown in FIG.
As described above, it is inserted into the hollow portion of the insulating case containing the toroidal soft magnetic material. At the time of this insertion, if the cross section of the lead and the cross section of the insulating case hollow portion have the same shape, it is easy to insert, the steps such as the bonding step can be omitted, and the lead does not fall off when mounting to the board,
It is preferable that the cross section of the lead and the cross section of the hollow portion of the insulating case are the same, for example, square.

There is no particular problem with the insulating case as long as the material can provide insulation, but epoxy, silicone, polybutylene terephthalate (PBT), liquid crystal polymer and the like are preferable. In recent years, since the leads are joined to the mounting substrate by heat treatment such as a reflow process during surface mounting, an insulating resin having excellent heat resistance, for example, a liquid crystal polymer is desirable.

The shape of the case is desirably a rectangular shape, particularly a rectangular parallelepiped. If the surface is flat like a rectangular parallelepiped, it is easy to carry out suction and conveyance by a mounting device when mounting on a substrate. Also, the size of the insulating case is not particularly limited, but it is preferable that the length of the case in the height direction is smaller than the length in the vertical direction and the horizontal direction as shown in FIG. As described above, the mounting of magnetic components in recent years has been advanced by mechanization, and the mounting of the magnetic components has often been performed by a suction conveyance device. At the time of this mounting, a magnetic component having a height that is too high tends to cause troubles such as falling when placed on a substrate. To address this issue,
If an insulating case with a low height is used, it is stable when installed on a substrate and troubles such as falling down are reduced.

FIG. 3 shows the body and lid of the insulating case.
It is preferable that the shape is as shown in FIG. In particular, if the protrusion of the lid is formed into the hollow portion of the magnetic core, the lead can be easily fixed, and the magnetic core can be fixed in the case, so that the magnetic core is not damaged in the case due to vibration and the yield is improved. Also, when the lead is inserted from the lid when inserting the lead,
The case body and the lid do not need to be disassembled. Normally, the case body and the lid are simply fitted and fixed by welding such as ultrasonic welding or an adhesive, but if too much force is applied when inserting the lead, the case body and the lid may be disassembled. A protrusion is provided for inserting and fixing the lead to the lid for easy separation.

There is no problem if the shape of the hollow portion of the case lid is adjusted to the cross section of the lead.
Within this range, the mountability is good and sufficient fixing strength is obtained, and it is not necessary to fix the lead and the case with an adhesive.
If it is smaller than the cross-sectional shape of the lead by 5% or more, the shape of the hollow portion becomes too small and the mounting property is deteriorated, and an extra force is applied at the time of mounting, leading to breakage of the lead and the magnetic core. On the other hand, if it is more than 5%, the size of the hollow portion becomes too large and sufficient fixing strength cannot be obtained, so that an adhesive step is required, which is not preferable.

Further, as shown in FIG. 4, the entrance shape of the hollow portion is made the same as the cross section of the lead, and the inner surface of the hollow portion is made convex in a circular shape, thereby facilitating the insertion of the lead and sufficiently fixing the lead. It is possible to obtain strength. It is preferable that the total value of the maximum heights of the protrusions is also within 5% of the height direction of the lead.

The magnetic component with a lead mounted on the surface of the present invention can be used as a normal normal mode choke coil or a common mode choke coil even though it is the same product, depending on how the conductors of the leads are connected on the substrate. become able to.

For example, when a lead in which two conductors are integrated is used, both ends of the conductor of the first lead are A and A '.
And both ends of the second conductor are B and B ′. As a normal normal mode choke coil, when B and A 'are connected on a substrate as shown in FIG. 5A, the circuit is in a normal mode as shown in FIG. 5B.

When a lead having three conductors integrated is used, both ends of the conductor of the third lead are C and C '.
In this case, by connecting B and A 'and C and B', respectively, an effect of three turns = 3 turns can be obtained.

On the other hand, as shown in FIG.
If B and B 'are used without being connected, they can be used as a common mode choke coil as shown in FIG. When used as a common mode choke coil, the number of conductors must be even.

The soft magnetic material forming the leaded magnetic component of the present invention is not particularly limited, but is preferably an amorphous alloy or an Fe-based magnetic alloy having a fine crystal structure described below.

As the amorphous alloy, an Fe-based amorphous alloy,
Co-based amorphous alloys and Fe-Ni-based amorphous alloys are preferred. As the Fe-based and Co-based amorphous alloys, those satisfying the following general formula 1 are preferable.

Formula 1: (M _{1 -a} M ′ _a ) _{100-b Xb In the} formula, M is at least one element selected from Fe and Co, and M ′ is Ti, V, Cr, Mn, Ni, Cu, Z
X represents at least one element selected from r, Nb, Mo, Ta and W, and X represents at least one element selected from B, Si, C and P, and 0 ≦ a ≦ 0.5 and 10 ≦ b ≤35
(Each number is at%).

Here, the M element becomes Co or Fe, and the composition ratio is adjusted according to required magnetic properties such as magnetic flux density, iron loss, sensitivity to minute current, etc.
It is an element necessary for controlling corrosion resistance and crystallization temperature,
Preferably, they are Cr, Mn, Nb, and Mo. The X element is an element necessary for obtaining an amorphous alloy. In particular, B is an element effective for amorphization, and Si is an amorphous element. Is an element that is effective for assisting in increasing the crystallization temperature.

As the Fe—Ni-based amorphous alloy, those satisfying the following general formula 2 are preferable. General formula 2: (Ni _1-a Fe _a ) _100-xyz M _x Si _y B
_{In the} formula, M is V, Cr, Mn, Co, Nb, Ta, W, Z
represents at least one element selected from r, and 0.2 ≦
a ≦ 0.5, 0.05 ≦ x ≦ 10, 4 ≦ y ≦ 12, 5 ≦
z ≦ 20 (each figure is at%). The Fe-Ni-based amorphous alloy can be manufactured at a lower cost than the above-mentioned Co-based material by using the Ni-rich Fe-Ni-based as a base, and has good magnetic properties. Here, the M element is an element necessary for controlling thermal stability, corrosion resistance, and crystallization temperature, and is preferably Cr, Mn, Co, or Nb.

As a method for producing an amorphous alloy, a liquid quenching method is preferable. For example, it can be obtained by quenching an alloy material adjusted to a predetermined composition ratio from a molten state at a cooling rate of 10 ⁵ ° C / sec or more. Such liquid quenching methods are usually
This is a method called a single roll method or a twin roll method, and the obtained amorphous alloy is obtained as a ribbon. The thickness of the ribbon is 30 μm or less, preferably 20 μm or less, and more preferably 8 to 15 μm. By controlling the thickness of the ribbon, a reactor with low loss can be obtained.

The Fe-based magnetic alloy having a fine crystal structure preferably satisfies the following general formula 3. Formula _{3: Fe a Cu b M c} Si d B e wherein, M is the Periodic Table 4a, 5a, 6a group element or Mn,
At least one or more elements selected from Ni, Co, and Al; a + b + c + d + e = 100 at%, 0.0
1 ≦ b ≦ 4, 0.01 ≦ c ≦ 10, 10 ≦ d ≦ 25, 3
≦ e ≦ 12. Here, Cu is an element effective in improving corrosion resistance, preventing coarsening of crystal grains, and improving soft magnetic properties such as iron loss and magnetic permeability, and the M element is effective in making the crystal diameter uniform. In addition, it is an element effective for reducing magnetostriction and magnetic anisotropy and improving magnetic properties with respect to temperature change. As the fine crystal structure, 50 to 300 Å of crystal grains are contained in the alloy in an area ratio of 50% or more, preferably 90% or more.
This is the state that exists.

As a method for producing an Fe-based magnetic alloy having a fine crystal structure, an amorphous alloy ribbon is obtained by a liquid quenching method, and then the crystallization temperature of the amorphous alloy is -50 to +12.
Heat treatment at 0 ° C. for 1 minute to 5 hours can be performed to precipitate fine crystals, or a method of directly depositing fine crystals by controlling the quenching rate of the liquid quenching method.

After obtaining such a magnetic ribbon such as an amorphous alloy ribbon or an Fe-based magnetic alloy ribbon having a fine crystal structure,
A magnetic core is formed by winding or laminating these ribbons, and then an insulating sheathing process is performed to form a reactor.

It is preferable to perform a heat treatment in a magnetic field in which a heat treatment is performed while applying a magnetic field perpendicularly (in the width direction of the magnetic core) or parallel to the magnetic path length direction of the above-mentioned magnetic core before or after the insulating sheathing treatment. As a heat treatment condition in a magnetic field, a slight inclination is allowed as long as a magnetic field is effectively applied in a vertical direction or a parallel direction. The heat treatment in a magnetic field may be performed continuously as a treatment subsequent to the heat treatment for removing the strain after the magnetic core is formed, or may be once cooled after the heat treatment for removing the strain and then heat-treated in the magnetic field again. The magnetic field may be applied for the first time during the heat treatment in the magnetic field, or may be applied during the strain relief heat treatment.

The heat treatment temperature in a magnetic field may be lower than the Curie temperature, and is practically 100 ° C. or higher, and more effective at 180 ° C. or higher. The atmosphere may be any of an inert atmosphere such as nitrogen and argon, a vacuum, a reducing atmosphere such as hydrogen gas, and the atmosphere. The heat treatment time is preferably about 10 minutes to 3 hours, particularly preferably 1 hour.
5 to 60 minutes.

As the above-mentioned insulating sheath, there are two types of interlayer insulating between magnetic ribbons and insulating core sheath. The magnetic ribbon forming the reactor is subjected to interlayer insulation treatment to obtain insulation. Regarding the insulation treatment, an insulating coating of a metal oxide such as magnesia, alumina, silica, zirconia is provided on the surface of the ribbon in order to obtain interlayer insulation. Then, it is stored in the above-mentioned insulating case.

[0040]

(Embodiment 1) An embodiment in the case of using as a noise reducing inductance element (normal mode choke coil) will be described.

As a soft magnetic material, a Co-based amorphous alloy ribbon (thickness: 17 μm) was formed in a toroidal shape,
m, an inner diameter of 2 mm, and a height of 6 mm were prepared and heat-treated. A rectangular parallelepiped (6 mm wide x 8 mm long x 5 mm high) made of a liquid crystal polymer was used as the insulating case, and the shape of the hollow portion for lead insertion was 1.5 mm wide x 0.2 m high.
m.

Two tin-plated rectangular soft copper wires (CU Joiner CUJ manufactured by Hitachi Cable, Ltd.) were placed in parallel as leads, partitioned and covered with a polyester insulator, and integrated.
These soft magnetic material, insulating case, and lead were assembled into a noise reduction element. This element was connected as shown in the circuit pattern of FIG. 5 (a), and the circuit was configured to have two turns.

The present element and this pattern were introduced in series into a secondary rectifier diode of a DC / DC converter (200 kHz) input 24 V, output 5 V-1 A circuit as shown in FIG.

(Embodiment 2) The lead has three conductors.
The measurement was performed under the same conditions as in Example 1. (Comparative Example 1) Output noise was measured when no noise reduction element was used (no noise measures were taken).

Comparative Example 2 For comparison, a bead-shaped Amobead (r) (size 4 × 2 × 6 W; the same size as in Example 1) manufactured by Toshiba was used by inserting it into a diode lead.
The output noise was compared under the same conditions as in the first embodiment.

[0046]

[Table 1]

Compared with the comparative example, the lead having two conductors was confirmed to have about twice the noise suppression effect, and the lead having three conductors was confirmed to have about three times the effect. From this result, by increasing the number of lead conductors,
It can be seen that the desired noise suppression effect is obtained.

(Embodiment 3) As an application of the present element,
If the circuit connection pattern was connected as shown in FIG. 6A, it could be used as a common mode choke coil.

[0049]

As described above, the noise reduction element of the present invention can have a plurality of winding effects by using a lead in which a plurality of conductors are integrated, and the shape of the insulating case can be changed to a rectangular parallelepiped. By doing so, it is possible to improve the surface mountability. In addition, by selecting the method of connecting the conductor on the substrate, it can be used as a choke coil in either a normal mode or a common mode.

[Brief description of the drawings]

FIG. 1 is a diagram showing a lead shape according to the present invention.

FIG. 2 is a view showing a magnetic component with leads of the present invention.

FIG. 3 is a diagram illustrating an example of a configuration of an insulating case of the present invention.

FIG. 4 is a diagram illustrating an example of a shape of a hollow portion of the insulating case of the present invention.

FIG. 5 (a) is a circuit pattern connection method representing a normal noise reduction element of the present invention. (B) A circuit diagram when the connection method of (a) is performed.

FIG. 6A is a circuit pattern connection method representing a common mode noise reduction element of the present invention. (B) A circuit diagram when the connection method of (a) is performed.

FIG. 7 is a circuit diagram used in Embodiment 1 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1 '... Conductor which comprises a lead 2 ... Insulator which comprises a lead 3 ... Insulating case 4 ... Hollow part 5 ... Body part of an insulating case 6 ... Magnetic core 7 ... Cover part of an insulating case 8 ... Mounting board 9 ... Projection part 10: convex shape in hollow part

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Claims (10)

[Claims] 1. A magnetic component in which a toroidal soft magnetic material is housed in an insulating case, wherein the soft magnetic material and the insulating case are provided with a hollow portion through which leads are inserted. A lead made of the above conductor is inserted therethrough. 2. The magnetic component with a lead according to claim 1, wherein the layers between the conductors of the lead are insulated and integrated. 3. The magnetic component with a lead according to claim 1, wherein the cross section of the lead is square. 4. The magnetic component with a lead according to claim 1, wherein the hollow portion of the insulating case has the same shape as the cross section of the lead. 5. The magnetic component with leads according to claim 1, wherein the shape of the insulating case is a rectangular parallelepiped. 6. The insulating case according to claim 1, wherein the length in the height direction is smaller than the length in the vertical direction and the horizontal direction.
6. The magnetic component with a lead according to any one of items 5 to 5. 7. The leaded magnetic component according to claim 1, wherein the soft magnetic material is an amorphous alloy ribbon. 8. A magnetic component in which a toroidal soft magnetic material is housed in an insulating case, wherein the soft magnetic material and the insulating case are provided with a hollow portion through which leads are inserted. A noise reduction circuit comprising: mounting a magnetic component with a lead through which a lead made of a conductor is inserted on a circuit board, wherein the conductors are not connected to each other. 9. A magnetic component in which a toroidal soft magnetic material is housed in an insulating case, wherein the soft magnetic material and the insulating case are provided with a hollow portion for inserting a lead, and the hollow portion has two or more pluralities. In a noise reduction circuit in which a magnetic component with a lead through which a lead made of a conductor is inserted is attached to a circuit board, one end of one conductor is connected to the opposite end of an adjacent conductor. Noise reduction circuit. 10. The noise reduction circuit according to claim 8, wherein the soft magnetic material is an amorphous alloy ribbon.