JPH0897045A - Wound magnetic core, pulse transformer provided therewith, and pc card for interface - Google Patents

Abstract

PURPOSE: To realize a pulse transformer which meets frequency characteristics in impedance prescribed by 'INS NET 64' by a method wherein a wound magnetic core which is set higher than a specific value in effective AC relative initial magnetic permeability and kept in a specific range of permeability even if an ambient temperature changes is utilized. CONSTITUTION: A wound magnetic core 1 is so set as to be more than about 50,000 in effective AC relative initial magnetic permeability K.μri under conditions that an ambient temperature is 20 deg.C, frequency is 20KHz, and a magnetic field is 0.05A/m in intensity. The wound magnetic core 1 is set to change in effective AC relative initial magnetic permeability K.μri by below ±20% with a temperature change in an ambient temperature range of -40 deg.C to 85 deg.C. The surface of the wound magnetic core 1 is coated with insulating epoxy resin. Then, windings 2 and 3 are wound around the magnetic core 1 by a specific number of turns in bifilar winding, cut in prescribed lengths, and soldered, and the wound magnetic core 1 is inserted into a phenol resin case 5 equipped with surface-mount lead terminals 4 and soldered at a prescribed position. Furthermore, a plate 6 is inserted in the upperside of the case 5 and bonded for the formation of a pulse transformer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin winding magnetic core and a pulse transformer using the same, and more particularly to an electronic device for a digital transmission system such as a PCMCIA2.0 compatible ISDN (Integrated Service Digital Network) interface PC card. The present invention relates to a magnetic core used for a pulse transformer used, a pulse transformer using the same, and an interface PC card using the magnetic core.

[0002]

2. Description of the Related Art A pulse transformer for S interface of ISDN is, for example, edited by ISDN Promotion Department of Nippon Telegraph and Telephone Corporation, technical reference material "Ins Net Service Interface 2nd Volume (Layer 1, Layer 2)" issued by the Telecommunications Association of Japan. Edited by CCITT (International Telegr)
It must be designed and manufactured to meet the electrical characteristics specified by the aph and Telephone Consultative Committee).

The two 64 kb / s described in Document 1 above
In the pulse transformer for S interface which can utilize s information channel and one 16 kb / s signal channel, the primary winding impedance is p. 37 of the above-mentioned document 1 when the frequency is f in the frequency band of 2 kHz to 20 kHz. From the rules on page 55 to
Impedance equal to or higher than the value given by the expression 0.125 · f, that is, inductance equal to or higher than 19.9 mH is required.

As is well known, since the AC ratio initial permeability μri of the magnetic core decreases as the frequency f increases, the lower limit value of the primary winding impedance of the pulse transformer defined in Document 1 is most strict. 20kHz
The lower limit value of the primary winding impedance at 20 kHz is 2500Ω, and the lower limit value of the primary winding inductance at 20 kHz is 19.9 mH.

There are PCMCIA 2.0 compatible PC cards of type I having a height of 3.3 mm, type II having a height of 5 mm, and type having a height of 10.5 mm.
The height of the pulse transformer used for the card is about 2.8 mm or less for Type I, with the terminals for surface mounting provided.
Type II is less than 3.6 mm and type III is 8.
It is necessary to make it about 9 mm or less, and it is desired that the mounting area of each type is 12.7 mm × 12.7 mm or less.

The above-mentioned pulse transformer for ISDN interface needs to satisfy the safety standard established in each country. Taking the dielectric strength between the primary winding and the secondary winding and between each winding and the magnetic core as an example, for example, AC 0.5 in Japan
kV, AC1.5kV in USA, AC2kV in European countries
To AC 4 kV.

In particular, it is preferable that the ISDN interface pulse transformer for the United States or Europe, which has a high withstand voltage, is entirely resin-molded so that the above withstand voltage can be satisfied with a margin.

Further, the pulse transformer for ISDN interface is required to satisfy the electrical characteristics defined in Document 1 in the entire range of the ambient temperature range determined for each area where it is used. For example, the strictest specification in the United States requires an ambient temperature of -40 ° C to 85 ° C.

As the pulse transformer for the ISDN interface, for example, the nominal value of the AC relative initial permeability μri is 100 as described in JP-A-2-235307.
Mainly used are EI-type cores and EE-type cores in which the coupling surface of the magnetic core is mirror-polished using ferrite of 00 or more, or V-shaped or day-shaped magnetic cores without cut surfaces or toroidal-shaped magnetic cores. There is.

In order to further miniaturize the pulse transformer, a low content of 60 atomic% or more of Fe described in JP-A-2-295101 and 50% or more of microstructured grains having a grain size of less than 100 nm is used. Magnetostrictive Fe-based alloy with squareness ratio Br / Bs of less than 0.2 and 10k
AC ratio of Hz, initial permeability μri is 20,000 to 50,000
A pulse transformer using a magnetic core in the range of is has been proposed. If a winding magnetic core having an outer diameter of 14 mm, an inner diameter of 7 mm, and a height of 6 mm is wound with about 40 turns, the ISDN pulse transformer for S interface can be obtained. Implementation examples are also described.

[0011]

[Problems to be Solved by the Invention] As the ferrite core having an AC relative initial magnetic permeability μri having a nominal value of 10000 or more, Tokin 12001H having a μri nominal value of 12000 and H25Z manufactured by Fuji Electric Chemical Co., Ltd. and a TDK having a nominal value of μri of 10000 are used. H5C2 and GP-11 made by Hitachi Ferrite are known.

However, it is known that μri of these ferrite magnetic cores greatly changes depending on the ambient temperature,
-4, which is the lower limit of operating temperature specified for North American communication equipment
At 0 ° C, the temperature drops to about 50% of that at 20 ° C. For this reason, when a pulse transformer that satisfies the standards of Document 1 above in the operating range of -40 ° C to 85 ° C is constructed by using a toroidal type, mouth-shaped or day-shaped magnetic core without a cut surface, a frequency of 20 kHz Μri at 6000
As a degree, a pulse transformer must be designed.

Further, when the entire pulse transformer is resin-molded as described above, in order to relieve the stress applied to the ferrite core by the resin molding, for example, the entire pulse transformer is once covered with silicone resin and then epoxy resin molding is performed. Although the treatment is used in practice,
In this case, μri at a frequency of 20 kHz at -40 ° C is 6
It deteriorates from about 000 to about 5,000. For this reason, when a resin-molded pulse transformer with an operating range of -40 ° C to 85 ° C is manufactured using a ferrite core, frequency 2
The μri at 0 kHz should be designed to be about 5000.

In order to obtain a large inductance, the effective area Ae of the magnetic core must be increased or the number of turns N must be increased. However, increasing the effective area Ae leads to an increase in the size of the magnetic core, and increasing the number of turns N leads to an increase in the stray capacitance Cs due to the winding and causes a deterioration in the transmission characteristics.

For example, when a ferrite core having a μri of 5000 is used and a mounting area is 12.7 mm × 12.7 mm, and a pulse transformer for an S interface of ISDN of the US specification is constructed, transmission characteristics, temperature characteristics and reliability are obtained. There is a problem in practical use, such as the PCMCIA
It is difficult to set the height to 2.8 mm or less and 3.6 mm or less so that it can be mounted on a 2.0-compatible PC card type I or type II.

On the other hand, the Fe-based alloy having a small magnetostriction containing 60 atomic% or more of Fe and 50% or more of microcrystalline grains having a grain size of less than 100 nm, as described in JP-A-2-295101, For details, see Japanese Patent Laid-Open No. 63-
As described in 239906, it is manufactured by a single roll method or the like, and is industrially manufactured as a thin band having a thickness of about 10 μm to 30 μm from the viewpoint of production efficiency and manufacturing yield.

In the case of a magnetic core using this Fe-based alloy ribbon,
Generally, it is used as a wound magnetic core and is inserted in a case made of phenol resin or the like. In this case, the space factor K = Ae / A, which is the ratio of the apparent magnetic core cross-sectional area A and the effective cross-sectional area Ae excluding the case, is defined by the thickness of the Fe-based alloy ribbon used, the surface roughness, Although it depends on the tension applied when the alloy ribbon is formed as a magnetic core, it is practically set to about 0.8 or more. further,
When the winding core is provided with the winding core, in order to ensure insulation between the winding core and the winding, and to prevent the characteristics of the winding core from changing due to stress unavoidably applied from the outside, As described above, the space factor K ′ of the magnetic core when it is inserted in a case made of phenol resin or the like is reduced to about 0.5 or less.

Therefore, in the case of a wound magnetic core described in JP-A-2-295101 in which a Fe-based nanocrystalline soft magnetic alloy magnetic core is inserted in a case, the space factor K'of the wound magnetic core and the frequency of 10 k are set.
The effective AC ratio initial permeability K ′ · μri in the state of being inserted in the case represented by the product of the AC ratio initial permeability μri at Hz is
If K'is 0.5, 10000 ≤ K '・ μri ≤ 2500
It becomes 0.

On the other hand, when the ISDN pulse transformer for the SDN is constructed by using the wound magnetic core, the stray capacitance due to the winding is suppressed so as not to cause the deterioration of the transmission characteristics, and the small size can easily satisfy the safety standard. From the meaning, it is also necessary to set the number of turns of the primary winding to about 60 turns or less.

For this reason, the AC ratio initial magnetic permeability μri at a frequency of 10 kHz described in JP-A-2-295101 is 50.
000, and the space factor K'when the winding core is inserted into the case is 0.5, that is, the effective AC ratio when the winding core is inserted into the case, the initial permeability K'.μri is 25000. With the number of turns of the primary winding set to 60 turns, the temperature range is -4
0 to 85 ℃, mounting area 12.7mm × 12.7mm
When ISDN S interface pulse transformer is configured, the height can be mounted on PCMCIA2.0 compatible interface PC card type I or type II with a height of 2.8 mm or less and 3.4 mm.
The following is difficult.

Further, in the magnetic core described in JP-A-2-295101, as described in detail in JP-A-1-247557, while applying a magnetic field parallel to the axis of rotation of the winding core, the squareness ratio Br is increased. There is also a problem in that a heat treatment must be performed to reduce / Bs to 0.2 or less, and a special heat treatment furnace having a magnetic circuit for applying the above magnetic field to the heat treatment core is required. It was

[0022]

According to the present invention, the average plate thickness tμm and the width H produced by the liquid quenching method are 0.5 mm≤H≤3.
mm of amorphous soft magnetic alloy ribbon is wound and then heat-treated so that the fine magneto-crystalline grains having a crystal grain size of 50 nm or less occupy at least 50% or more of the entire volume of the structure, the saturation magnetostriction constant λs Ae / A, which is the ratio of the apparent magnetic core cross-sectional area A excluding the insulating coating and the effective cross-sectional area Ae, in a winding core whose surface has an absolute value of 1.0 x 10 ^-6 or less The occupied space factor K is t /
(T + 5) ≦ K ≦ t / (t + 2), the ambient temperature is 20 ° C., the frequency is 20 kHz, and the magnetic field strength is 0.05 A / m. The AC ratio is expressed by the product of the initial permeability μri and the space factor K. Effective AC ratio Initial permeability K · μri is 50,000 or more, and ambient temperature is −
The wound core has a temperature change of the effective AC ratio initial magnetic permeability K · μri within ± 20% in the range of 40 ° C to 85 ° C.

By using the wound magnetic core having such characteristics, "I" can be obtained in the ambient temperature range of -40 ° C to 85 ° C.
It is possible to realize a pulse transformer having a height of about 2.8 mm or less, which is required for a PCMCIA 2.0 type I PC card that satisfies the impedance frequency characteristics specified by NS Net 64 ″.

In the wound magnetic core, particularly, the ambient temperature is 20
The effective AC ratio initial permeability K · μri represented by the product of the space factor K and the AC ratio initial permeability μri when the temperature is 20 ° C., the magnetic field strength is 0.05 A / m, and the magnetic field strength is 0.050 or more, and −40.
When the temperature change of the effective AC ratio initial permeability K · μri is within ± 10% in the ambient temperature range of ℃ to 85 ℃, in the temperature range of -40 ℃ to 85 ℃, "IN
It meets the impedance frequency characteristics specified by S-net 64 ", and the height required for PCMCIA 2.0 type I PC card can be set to about 2.8 mm or less, which is required by European safety standards. It is possible to realize a resin-molded pulse transformer that also satisfies the required withstand voltage AC4kV.

In the above wound magnetic core, when the surface of the wound magnetic core is provided with an insulating coating of epoxy, nylon, polyimide or parylene, or a multi-layer insulating coating containing at least one of these, insulation is obtained. Since the insulation between the winding and the winding core can be secured even if the thickness of the coating is thinned, the space factor K'after coating can be increased, and the stress applied to the winding core by the coating is relatively small, so the stress of the magnetic characteristics Since the deterioration is small, the AC ratio initial permeability μri at an ambient temperature of 20 ° C., a frequency of 20 kHz, and a magnetic field strength of 0.05 A / m is preferably smaller than that before coating, which is preferable.

In the above pulse transformer, when an insulating layer is provided between the first winding and the second winding of the pulse transformer, the coupling degree between the two windings is not significantly reduced. This is preferable because it is easy to secure the withstand voltage between the two windings.

Further, in the above-mentioned pulse transformer, the insulating layer provided between the first winding and the second winding of the pulse transformer is an insulating coating made of epoxy, nylon, polyimide or parylene, or of these. A multi-layer insulation coating containing at least one kind is preferable because the withstand voltage between the two windings can be easily obtained without significantly increasing the size of the pulse transformer.

Even a thin interface IC card using the pulse transformer according to the present invention, such as a PCMCIA 2.0 type I or type II compatible ISDN interface PC card, cannot be handled by conventional products. It is preferable because it can easily satisfy strict overseas safety standards in a wide temperature range of -40 ° C to 85 ° C.

[0029]

EXAMPLES Examples of the present invention will be described in detail below, but the present invention is not limited to these examples. (Example 1) ISD satisfying withstand voltage AC 1.5 kV
Satisfies N S interface standard and PCMC
IA 2.0 Type I compatible interface PC card with a height of 2.8 mm or less, a mounting area of 12.7 mm x 11 mm, and a small pulse transformer not entirely resin-molded were manufactured by the following method. did.

By the liquid quenching method using a single roll, the composition is Fe74Cu1Nb3Si17B5, the thickness t is 17 μm, and the width is 2
After manufacturing a 5.4 mm amorphous soft magnetic alloy ribbon, the amorphous soft magnetic alloy ribbon was slit to obtain a ribbon having a width of 1 mm.
Using this amorphous soft magnetic alloy ribbon having a width of 1 mm, an outer diameter of 8 mm is obtained by changing the space factor K represented by Ae / A, which is the ratio of the apparent sectional area A of the winding magnetic core to the effective sectional area Ae, Eight toroidal wound magnetic cores having an inner diameter of 4 mm and a height of 1 mm were manufactured.

Here, the dimension of the wound magnetic core is determined as described above because the dimension of the finished product of the pulse transformer is PCMCIA.
This is because the height required for mounting on a 2.0 type I compatible interface PC card is 2.8 mm or less, and the mounting area is 12.7 mm × 12.7 mm.

Next, these eight amorphous winding magnetic cores were 550
After heat-treating for 1 hour in a nitrogen atmosphere at ℃, gradually cooling, waiting for the temperature of the core to reach room temperature, insulating coating the surface of the core with an epoxy resin, and comparing with Invention 1 to Invention 4. The wound magnetic cores of Examples 1 to 4 were obtained.

The amorphous soft magnetic alloy ribbon was 550
The soft magnetic alloy ribbon obtained by heat-treating for 1 hour in a nitrogen atmosphere at ℃ and slowly cooling the saturated magnetostriction constant λs with 90% or more of the entire structure occupied by fine crystals with a grain size of 50 nm or less. is + 0.3 × 10 ^- it was ^6.

The wound magnetic cores of the present inventions 1 to 4 and the comparative examples 1 to 4 and the toroidal Mn-Zn ferrite cores having an outer diameter of 9 mm, an inner diameter of 4 mm and a height of 1 mm were insulation-coated with an epoxy resin. The saturation magnetic flux density Bs, the squareness ratio Br / Bs, and the frequency of 20 kHz in the DC magnetic characteristics of the nine magnetic cores of Comparative Example 5 at an ambient temperature of 20 ° C.
z, AC ratio initial permeability μri when the magnetic field strength is 0.05 A / m, and effective AC ratio initial permeability K · μr which is the product of this μri and the space factor K of the magnetic core excluding the insulating coating.
i and the rate of change Δ of the effective AC ratio initial permeability K · μri when the ambient temperature is changed from −40 ° C. to 85 ° C.
Table 1 shows the measurement results of K · μri. The size of each magnetic core after insulation coating is 8.5 mm in outer diameter and 3.5 mm in inner diameter.
mm, height 1.5 mm.

[0035]

[Table 1]

A pulse transformer was manufactured by using the above-mentioned nine magnetic cores and by the same method as described in detail below. Table 2 shows the magnetic core 1 whose surface is shown in FIG. 1 (a), which is insulation-coated with epoxy, and the winding 2 and the winding 3 made of a polyurethane-coated electric wire (first type UEW) with a diameter of 0.05 mm. Bifilar winding is performed by the number of turns described to form a pulse transformer as shown in FIG.

The number of turns of each transformer shown in Table 2 is as follows: ambient temperature 20 ° C., frequency 20 kHz, magnetic field strength 0.05 A /
The inductance at m was selected to be the smallest integer value of 23.9 mH or more. The value of this inductance is
It is 1.2 times the inductance value 19.9 mH corresponding to the impedance shown in the DSU impedance template of FIG. 8.6 and the TE impedance template of FIG.

After cutting both ends of the windings 2 and 3 of the pulse transformer 4 shown in FIG. 1 (b) to a predetermined length, soldering is performed, and a surface mounting lead terminal 4 is provided for 12.7 mm.
It is inserted in a phenol resin case 5 of 11 mm x 2.8 mm, and both ends of the windings 2 and 3 are soldered to predetermined positions of the surface mount lead terminals 4 as shown in Fig. 1 (c).

A phenol resin plate 6 is inserted and adhered to the upper surface of a phenol resin case 5 in which the pulse transformer shown in FIG. 1 (c) is inserted to form a pulse transformer as shown in FIG. 1 (d).

The mounting area of this pulse transformer is 12.7 m.
m × 11 mm, height is 2.8 mm. Table 2 shows the evaluation results of the pulse transformer.

[0041]

[Table 2]

In Table 2, the impedance characteristics are marked with a circle when the impedance is larger than the impedances shown in the DSU impedance template of FIG. 8.6 and the TE impedance template of FIG.

The transmission characteristics were evaluated as ◯ when the electric characteristics described on pages 37 to 55 of the above-mentioned document 1 were satisfied by using an IC145 terminal device IC, MC145474 manufactured by Motorola.

Regarding the insulation characteristics, a voltage of AC 1.5 kV was applied for 1 minute between each winding and between the winding and the case, and it was inspected whether insulation breakdown occurred. If no insulation breakdown occurred, ○, Dielectric breakdown was designated as x.

As can be seen from Table 2, when the number of turns of each winding corresponding to PCMCIA 2.0 type I exceeds 60 turns in the structure of this embodiment, it becomes impossible to satisfy the withstand voltage AC 1.5 kV. It was

Here, to set the winding to 60 turns or less,
From the relationship between Table 1 and Table 2, the ambient temperature of the magnetic core forming the pulse transformer is 20 ° C., the frequency is 20 kHz, and the magnetic field strength is 0.0.
Effective AC ratio at 5 A / m Initial permeability K · μri is 500
It turned out that more than 00 is required.

After the insulating coating, the winding core has an ambient temperature of 20 ° C., a frequency of 20 kHz, and a magnetic field strength of 0.0.
Effective AC ratio at 5 A / m Initial permeability K · μri is 500
In order to make it 00 or more, the crystal grain size of the wound magnetic core is 5
Saturation magnetostriction constant λ of the soft magnetic alloy ribbon occupying at least 50% or more of the entire volume of the structure with fine crystal grains of 0 nm or less
The absolute value of s is 1.0 × 10 ^-6 or less, and the space factor which is the ratio of the apparent magnetic core cross-section A excluding the insulating coating and the average core thickness t of the soft magnetic alloy ribbon and the effective cross-section Ae K is t /
It was also found that it must be in the range of (t + 5) ≦ K ≦ t / (t + 2).

As a result of measuring the temperature characteristics of the impedance characteristics of the transformers of the present invention A to D and comparative examples A to E in the range of −40 ° C. to 85 ° C., all pulse transformers except comparative example E It was found that the impedance characteristics defined by the ISDN S interface are satisfied.

It was also confirmed that if the operating temperature range of the MC145474, the ISDN terminal device IC used for evaluation of the transmission characteristics is expanded, the transmission characteristics can be sufficiently satisfied even in a wide temperature range of -40 ° C to 85 ° C. .

As a result of further detailed examination, a pulse transformer having a structure not entirely resin-molded is -40.
In order to satisfy the characteristics defined by the ISDN S interface in the range of ℃ to 85 ℃, the effective AC ratio of the winding core is -40 ℃ to 85 ℃ of initial permeability K · μri.
It was also found that the temperature change in the range of 10% must be within ± 20%.

(Embodiment 2) PC satisfying the standard of ISDN S interface satisfying withstand voltage AC4kV
MCIA 2.0 Type I compatible interface PC
A pulse transformer which satisfies the height required for the card of 2.8 mm or less and has a small mounting area of 12.7 mm × 11 mm and which is entirely resin-molded was manufactured by the following method.

By the liquid quenching method using a single roll, the composition was Fe74Cu1Nb3Si17B5, the thickness t was 17 μm, and the width was 2
After manufacturing a 5.4 mm amorphous soft magnetic alloy ribbon, the amorphous soft magnetic alloy ribbon was slit to obtain a ribbon having a width of 1 mm.
Using this amorphous soft magnetic alloy ribbon having a width of 1 mm, an outer diameter of 8 mm is obtained by changing the space factor K represented by Ae / A, which is the ratio of the apparent sectional area A of the winding magnetic core to the effective sectional area Ae, Eight toroidal wound magnetic cores having an inner diameter of 4 mm and a height of 1 mm were manufactured.

Here, the dimension of the wound magnetic core is determined as described above because the dimension of the finished product of the pulse transformer is PCMCIA.
This is because the height required for mounting on a 2.0 type I compatible interface PC card is 2.8 mm or less and the mounting area is 12.7 mm × 11 mm.

Next, these eight amorphous winding magnetic cores were 550
After heat-treating for 1 hour in a nitrogen atmosphere at 0 ° C. and then gradually cooling, the temperature of the same winding core reached room temperature, the surface of the same winding core was insulation coated with an epoxy resin, and the invention 5 to invention 8 and comparative example 6 were obtained.
~ A wound magnetic core of Comparative Example 9 was obtained.

It should be noted that the amorphous soft magnetic alloy ribbon was 550
90% or more of the entire structure of the soft magnetic alloy ribbon obtained by heat-treating for 1 hour in a nitrogen atmosphere at ℃ and gradually cooling is 50
The saturation magnetostriction constant λs was + 0.3 × 10 ⁻⁶ in the state of being occupied by fine crystals of nm or less.

The present invention 5 to invention 8 and the wound magnetic cores of comparative examples 6 to 9 and an outer diameter of 9 mm and an inner diameter of 4 mm,
The saturation magnetic flux density Bs and the squareness ratio Br / Bs in the DC magnetic characteristics of the nine magnetic cores of Comparative Example 10 in which a toroidal Mn—Zn ferrite magnetic core having a height of 1 mm is insulation-coated with an epoxy resin at an ambient temperature of 20 ° C. , Frequency 20k
Hz, the AC relative initial permeability μri when the magnetic field strength is 0.05 A / m and the effective AC relative initial permeability K · represented by the product of this μri and the space factor K of the magnetic core excluding the insulating coating.
μri and the amount of change Δ in the effective AC ratio initial permeability K · μri when the ambient temperature is changed from −40 ° C. to 85 ° C.
Table 3 shows the measurement results of K · μri. The dimensions of each magnetic core after insulation coating are 8.5 mm outer diameter and 3.5 m inner diameter.
m, height 1.5 mm.

[0057]

[Table 3]

A pulse transformer was manufactured by using the above 9 magnetic cores and by the same method as described below in detail. The number of turns shown in Table 4 for each magnetic core is shown in Fig. 2 (a), with a magnetic core 11 having an epoxy insulation coating on the surface thereof, and a winding wire 12 made of a polyurethane-coated electric wire (first type UEW) having a wire diameter of 0.05 mm. 2B is wound evenly to form a coil as shown in FIG.

The number of turns of each transformer in Table 4 is as follows: ambient temperature 20 ° C., frequency 20 kHz, magnetic field strength 0.05 A /
It was selected to be the smallest integer value such that the inductance at m is 23.9 mH or more. The value of this inductance is the inductance value 1 corresponding to the impedance shown in the DSU impedance template of Figure 8.6 and TE impedance template of Figure 8.7 of Document 1 above.
It is 1.2 times that of 9.9 mH.

After inserting a silicon glass tube 13 of a predetermined length into both ends of the coil winding 12 shown in FIG. 2 (b), the surface of the coil is coated with epoxy as shown in FIG. 2 (c). Insulate coating.

In the coil shown in FIG. 2 (c) whose surface is insulation-coated with epoxy, the winding 14 made of a polyurethane-coated electric wire (first type UEW) having a wire diameter of 0.05 mm is shown in Table 4 for each magnetic core. The same number of turns is used to form a pulse transformer as shown in FIG.

After cutting both ends of the windings 12 and 14 shown in FIG. 2 (d) to a predetermined length, soldering is performed to make a phenol resin case 16 having surface-mounting lead terminals 15.
2 and solder both ends of the windings 12 and 14 to predetermined positions of the surface mount lead terminal 15 as shown in FIG. 2 (e).

Urethane resin is filled inside the phenol resin case 16 in which the pulse transformer shown in FIG. 2E is inserted and then cured to form a resin mold type pulse transformer as shown in FIG. 2F.

The mounting area of this pulse transformer is 12.7 m.
m × 11 mm, height is 2.8 mm. Table 4 shows the evaluation results of the pulse transformer.

[0065]

[Table 4]

In Table 4, the impedance characteristics are marked with ◯ when the impedance is larger than the impedances shown in the DSU impedance template of FIG. 8.6 and the TE impedance template of FIG.

The transmission characteristic was marked with "◯" when the electric characteristic described on page 37 to page 55 of the above-mentioned document 1 was satisfied by using MC145474, an ISDN terminal device IC manufactured by Motorola.

Regarding the insulation characteristics, a predetermined voltage was applied between the windings and between the magnetic core and the windings for 1 minute to examine whether dielectric breakdown occurred. A product with a withstand voltage of AC4kV is ◯, and a withstand voltage of AC1.5kV is satisfied, but AC4k
Those that do not satisfy the withstand voltage of V are indicated by Δ, and those that satisfy the withstand voltage of AC 0.5 kV but do not satisfy the withstand voltage of AC 1.5 kV are indicated by x.

As can be seen from Table 4, it was found that in the structure of this embodiment, when the number of turns of each winding corresponding to PCMCIA 2.0 type I exceeds 60 turns, the withstand voltage AC4kV cannot be satisfied.

Here, to set the winding to 60 turns or less,
From the relationship between Table 3 and Table 4, the ambient temperature of the magnetic core that constitutes the pulse transformer is 20 ° C, the frequency is 20 kHz, and the magnetic field strength is 0.0.
Effective AC ratio at 5 A / m Initial permeability K · μri is 500
It turned out that more than 00 is required.

After the insulating coating, the winding core has an ambient temperature of 20 ° C., a frequency of 20 kHz, and a magnetic field strength of 0.0.
Effective AC ratio at 5 A / m Initial permeability K · μri is 500
In order to make it 00 or more, the crystal grain size of the wound magnetic core is 5
Saturation magnetostriction constant λ of the soft magnetic alloy ribbon occupying at least 50% or more of the entire volume of the structure with fine crystal grains of 0 nm or less
The space factor that is the ratio of the apparent magnetic core cross-sectional area A excluding the insulating coating and the average core thickness t of the soft magnetic alloy ribbon and the effective cross-sectional area Ae when the absolute value of s is 1.0 × 10 ⁻⁶ or less. K is t /
It was also found that it must be in the range of (t + 5) ≦ K ≦ t / (t + 2).

As a result of measuring the temperature characteristics of the impedance characteristics of the transformers of the inventions E to H and comparative examples F to J in the range of −40 ° C. to 85 ° C., all the pulse transformers except comparative example J were It was found that the impedance characteristics defined by the ISDN S interface are satisfied.

It was also confirmed that if the operating temperature range of the MC145474, the ISDN terminal device IC used to evaluate the transmission characteristics was expanded, the transmission characteristics could be sufficiently satisfied even in a wide temperature range of -40 ° C to 85 ° C. .

As a result of further detailed examination, in order to satisfy the characteristics defined by the S interface of ISDN in the range of -40 ° C. to 85 ° C., the pulse transformer having a structure entirely molded with resin should have the above-mentioned volume. It was also found that the temperature change in the effective AC ratio initial permeability K · μri of the magnetic core in the range of -40 ° C to 85 ° C must be within ± 20%.

[0075]

As described above, according to the present invention, "I
A compact, high-performance pulse transformer that can be used for IC cards for NS Net 64 "with a mounting area of 12.7 mm x 12.7 mm or less and a height of 2.8 mm or less and that can meet the most strict European safety standards among the safety standards. Obtainable.

In the above description, "INS Net 6
The effectiveness of the present invention has been described by taking as an example a pulse transformer for an IC card or the like, which has the smallest mounting area and is required to be thin, among those for 4 ". Needless to say, it is effective in achieving both miniaturization and high performance of a pulse transformer used in the same frequency band as the pulse transformer for the INS net 64 ″ and other than this application.

[Brief description of drawings]

FIG. 1 is an explanatory view of a manufacturing process of an embodiment of a pulse transformer not entirely resin-molded according to the present invention.

FIG. 2 is an explanatory view of a manufacturing process of an embodiment of a pulse transformer which is wholly resin-molded according to the present invention.

[Explanation of symbols]

 1, 11 Insulated coated winding core 2, 3, 12, 14 Polyurethane-coated electric wire 4, 15 Surface mount lead terminal 5, 16 Phenol resin case 6 Phenol resin plate 13 Silicon glass tube

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location 4230-5E H01F 19/04 U (72) Inventor Hirohiko Miki 244 Katsuragi, Tottori City, Tottori Prefecture 9 Top Electronics Stock company

Claims (7)

[Claims] 1. An average plate thickness tμ manufactured by a liquid quenching method.
After winding an amorphous soft magnetic alloy ribbon having a width m of 0.5 mm ≦ H ≦ 3 mm, fine crystal grains having a grain size of 50 nm or less should occupy at least 50% or more of the entire volume of the structure. The absolute value of the saturation magnetostriction constant λs when heat-treated is 1.0
In a winding core having an insulating coating on the surface of the winding core having a size of 10 ⁻⁶ or less, the space factor K represented by Ae / A, which is the ratio of the apparent magnetic core cross-sectional area A excluding the insulating coating portion and the effective cross-sectional area Ae. Is t / (t + 5) ≦ K ≦ t / (t + 2),
Ambient temperature 20 ℃, frequency 20kHz, magnetic field strength 0.0
The effective AC ratio initial permeability K · μri represented by the product of the AC ratio initial permeability μri and the space factor K at 5 A / m is 5000.
In the range of 0 or more and the ambient temperature range of -40 ° C to 85 ° C, the temperature change of the effective AC ratio initial permeability K · μri is ±.
A wound magnetic core within 20%. 2. The wound magnetic core according to claim 1, wherein the ambient temperature is 20 ° C., the frequency is 20 kHz, and the magnetic field strength is 0.05 A.
In the range of the effective AC ratio initial magnetic permeability K · μri represented by the product of the AC ratio initial magnetic permeability μri and the space factor K above 50000 or more, and the ambient temperature range of −40 ° C. to 85 ° C. The temperature change of the effective AC ratio initial permeability K · μri is ± 1.
A wound magnetic core within 0%. 3. The wound magnetic core according to claim 1 or 2, wherein the surface of the wound magnetic core is epoxy, nylon,
Insulating coating with either polyimide or parylene, or at least one of these
A wound magnetic core characterized by having a multi-layer insulating coating containing at least one kind. 4. A pulse transformer comprising the wound magnetic core according to any one of claims 1 to 3. 5. The pulse transformer according to claim 4, wherein an insulating layer is interposed between the first winding and the second winding of the pulse transformer. 6. The pulse transformer according to claim 5, wherein the insulating layer provided between the first winding and the second winding of the pulse transformer is made of epoxy, nylon, polyimide or parylene. A pulse transformer which is an insulating coating or a multi-layer insulating coating containing at least one of these. 7. An interface P using the pulse transformer according to any one of claims 4 to 6.
C card.