JP2909392B2 - Wound core, pulse transformer using the same, and PC card for interface - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin wound magnetic core and a pulse transformer using the same, particularly to an electronic device for a digital transmission system such as a PC card for an ISDN (Integrated Service Digital Network) interface compatible with PCMCIA 2.0. 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 same.

[0002]

2. Description of the Related Art A pulse transformer for an ISDN S interface is disclosed in, for example, Technical Reference Material "INS Network Service Interface Volume 2 (Layer 1 and Layer 2)" published by the Telecommunications Association of Japan, edited by the ISDN Promotion Department. Ed.) CCITT (International Telegr
It must be designed and manufactured to meet the electrical characteristics specified by the aph and Telephone Consultative Committee.

[0003] The two 64 kb /
In the pulse transformer for S interface that can use s information channel and one 16 kb / s signal channel, in the frequency band of 2 kHz to 20 kHz, when the frequency is f, the primary winding impedance is page 37 of the above document 1. According to the provisions described on page 55 from
The impedance must be equal to or greater than the value given by the equation of 0.125 · f, that is, the inductance must be equal to or greater than 19.9 mH.

As is well known, since the AC ratio initial permeability μri of the magnetic core decreases with an increase in the frequency f, the lower limit value of the primary winding impedance of the pulse transformer specified in the above document 1 is strictest. Will be 20kHz
The lower limit of the primary winding impedance at 20 kHz is 2500Ω, and the lower limit of the primary winding inductance at 20 kHz is 19.9 mH.

[0005] PCMCIA 2.0 compliant PC cards include a type I having a height of 3.3 mm, a type II having a height of 5 mm, and a type having a height of 10.5 mm.
The height of the pulse transformer used for the card is approximately 2.8 mm or less for Type I
Type II is about 3.6 mm or less and type III is 8.
It is necessary to be about 9 mm or less, and it is desired that the mounting area of each type be 12.7 mm × 12.7 mm or less.

The pulse transformer for the ISDN interface must satisfy safety standards set in each country. For example, taking the withstand voltage between the primary winding and the secondary winding and between each winding and the magnetic core as an example, for example, AC0.5 in Japan
kV, 1.5kV AC in the US, 2kV AC in European countries
Or AC4 kV.

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

Further, the pulse transformer for the ISDN interface needs to satisfy the electrical characteristics specified in the document 1 in the entire range of the ambient temperature range determined for each region where the ISDN interface is used. For example, the strictest specifications in the United States require an ambient temperature of -40C to 85C.

As a pulse transformer for the ISDN interface, for example, as described in Japanese Patent Laid-Open No. 235307/1990, the nominal value of the AC ratio initial permeability μri is 100
An EI type core or EE type core having a core surface mirror-polished with a ferrite of at least 00 or more, or a mouth-shaped or sun-shaped core without a cut surface, or a toroidal-shaped core is mainly used. I have.

In order to further reduce the size of the pulse transformer, Japanese Patent Application Laid-Open No. 2-295101 discloses a low-voltage pulse transformer comprising 60 atomic% or more of Fe and having 50% or more of the structure composed of microcrystalline particles having a particle size of less than 100 nm. A magnetostrictive Fe-based alloy having a squareness ratio Br / Bs of less than 0.2 and 10 k
Hz AC ratio initial permeability μri is 20,000 to 50,000
A pulse transformer using a magnetic core having a diameter of 14 mm, an inner diameter of 14 mm, an inner diameter of 7 mm, and a height of 6 mm is wound around a turn of about 40 turns to provide the ISDN S interface pulse transformer. An embodiment to the effect is also described.

[0011]

The ferrite cores having an AC ratio initial permeability μri nominal value of 10,000 or more include Tokin's 12001H having a μri nominal value of 12000, H25Z manufactured by Fuji Electric Chemical, and TDK's TDK having a nominal μri value of 10,000. H5C2 and Hitachi Ferrite GP-11 are known.

However, it is known that the μri of these ferrite 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 standard of the above document 1 in the operating range of -40 ° C. to 85 ° C. is configured using a toroidal type, a mouth-shaped or a sun-shaped core without a cut surface, the frequency is 20 kHz. Μri at 6000
To the extent, a pulse transformer must be designed.

Further, when the entire pulse transformer is resin-molded as described above, in order to reduce the stress applied to the ferrite core by the resin mold, for example, the entire pulse transformer is once covered with silicon resin and then epoxy resin molding is performed. Processing is used practically,
In this case, μri at a frequency of −20 ° C. and a frequency of 20 kHz is 6
It deteriorates from about 000 to about 5000. For this reason, when manufacturing a resin-molded pulse transformer having an operating range of −40 ° C. to 85 ° C. using a ferrite core, the frequency 2
Μri at 0 kHz must be designed to be about 5000.

The only way to obtain a large inductance is to increase the effective area Ae of the magnetic core or increase the number of turns N. However, increasing the effective area Ae causes an increase in the size of the magnetic core, and increasing the number of turns N increases the stray capacitance Cs due to the windings, thereby deteriorating 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 to constitute a pulse transformer for S interface of ISDN of US specification, transmission characteristics, temperature characteristics and reliability are considered. Such as the PCMCIA.
It is difficult to make the height 2.8 mm or less and 3.6 mm or less that can be mounted on the type I or type II of the 2.0 compatible PC card.

On the other hand, an Fe-based alloy having a small magnetostriction, which is described in JP-A-2-295101 and contains microcrystalline particles containing at least 60 atomic% of Fe and having a structure of at least 50% having a particle size of less than 100 nm, The details are described in
As described in US Pat. No. 239906, it is manufactured by a single roll method or the like, and is industrially manufactured as a thin ribbon 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,
In general, it is used as a wound core and inserted in a case made of phenol resin or the like. In this case, the space factor K = Ae / A, which is the ratio between the apparent magnetic core cross-sectional area A and the effective cross-sectional area Ae excluding the case, is determined by the thickness, surface roughness, Although it depends on the tension applied when forming the alloy ribbon as a magnetic core, it is practically about 0.8 or more. further,
When the winding core is provided with a winding, to ensure insulation between the winding core and the winding, and to prevent the characteristics of the winding core from changing due to stress inevitably applied from the outside to the winding core, As described above, the space factor K ′ of the magnetic core when inserted into a case made of a phenol resin or the like is reduced to about 0.5 or less.

For this reason, in the case of a wound core in which an Fe-based nanocrystalline soft magnetic alloy core described in JP-A-2-295101 is inserted into a case, the space factor K 'of the wound core and the frequency of 10 k
The effective AC ratio initial permeability K ′ · μri in the state inserted in the case represented by the product of the AC ratio initial permeability μri in Hz is
If K ′ is 0.5, 10,000 ≦ K ′ · μri ≦ 2500
0.

On the other hand, when a pulse transformer for an ISDN S interface is formed using a wound core, the stray capacitance due to the winding is suppressed so as not to cause deterioration of the transmission characteristics, so that the size is small and safety standards can be easily satisfied. From the viewpoint, the number of turns of the primary winding must be about 60 turns or less.

For this reason, the AC ratio initial permeability μri at a frequency of 10 kHz described in JP-A-2-295101 is 50.
000, and a space factor K ′ of 0.5 when the core is inserted into the case, that is, a core having an effective AC ratio initial permeability K ′ · μri of 25000 when the core is inserted into the case. Assuming that the number of turns of the primary winding is 60 turns, a temperature range of -4
0 to 85 ° C, mounting area 12.7mm x 12.7mm
2.8mm or less and 3.4mm that can be mounted on a PCMCIA 2.0 compatible interface PC card type I or type II when the ISDN S interface pulse transformer is configured
It is difficult to:

Further, in the magnetic core described in the above-mentioned 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 wound core, the squareness ratio Br is increased. Heat treatment must be performed to make / Bs 0.2 or less, and there is also a problem that a special heat treatment furnace having a magnetic circuit for applying the above-described magnetic field to the magnetic core to be heat-treated is required. Was.

[0022]

According to the present invention, an average plate thickness t μm and a width H of 0.5 mm ≦ H ≦ 3 manufactured by a liquid quenching method.
mm of an amorphous soft magnetic alloy ribbon, and then heat-treated so as to occupy at least 50% or more of the entire volume of the structure with fine crystal grains having a crystal grain size of 50 nm or less. In a core in which the absolute value is 1.0 × 10 ⁻⁶ or less, the surface of the core is insulatively coated, and expressed as Ae / A which is a ratio of an apparent core cross-sectional area A excluding an insulating coating portion to an effective cross-sectional area Ae. Space factor K is t /
(T + 5) ≦ K ≦ t / (t + 2), represented by the product of the AC ratio initial permeability μri and the space factor K when the ambient temperature is 20 ° C., the frequency is 20 kHz, and the magnetic field strength is 0.05 A / m. Effective AC ratio initial permeability K · μri is 50,000 or more and ambient temperature −
The wound core has a temperature change of the effective AC ratio initial permeability K · μri within ± 20% from 40 ° C. to 85 ° C.

The use of a wound core having such characteristics allows the "I" in an ambient temperature range of -40.degree. C. to 85.degree.
It is possible to realize a pulse transformer having a height of about 2.8 mm or less required for a PCMCIA 2.0 type I PC card which satisfies the impedance frequency characteristics defined by the NS net 64 ".

In the above-mentioned wound core, in particular, at an ambient temperature of 20
° C, a frequency of 20 kHz, and a magnetic field strength of 0.05 A / m, the effective AC ratio initial permeability K · μri expressed by the product of the space factor K and the AC ratio initial permeability μri is 50,000 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 from 0 ° C. to 85 ° C., “IN” in the temperature range of −40 ° C. to 85 ° C.
The frequency characteristics of the impedance stipulated by S-net 64 "are satisfied, and the height required for PCMCIA 2.0 type I PC card can be about 2.8 mm or less. It is possible to realize a resin-molded pulse transformer that satisfies the required withstand voltage AC4 kV.

In the above-mentioned wound core, if the surface of the wound core is coated with an insulating coating of any of epoxy, nylon, polyimide or parylene, or a multi-layer insulating coating containing at least one of these, Even if the thickness of the coating is reduced, the insulation between the winding and the core can be ensured, so that the space factor K ′ after coating can be increased. Since 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 also hard to be smaller than before coating, which is preferable.

In the above-mentioned pulse transformer, when an insulating layer is interposed between the first and second windings of the pulse transformer, the degree of coupling between the two windings can be reduced without significantly lowering the degree of coupling between the two windings. This is preferable because it is easy to secure the dielectric strength between the two windings.

Further, in the above-mentioned pulse transformer, an insulating layer provided between the first winding and the second winding of the pulse transformer may be an insulating coating made of epoxy, nylon, polyimide or parylene, or an insulating coating made of any of these. It is preferable to use a multi-layer insulating coating containing at least one or more types 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 compliant interface PC card for ISDN, cannot be used with a conventional product. It is preferable because it can easily satisfy strict overseas safety standards in a wide temperature range from -40 ° C to 85 ° C.

[0029]

Embodiments of the present invention will be described below in detail, but the present invention is not limited to these embodiments. (Example 1) ISD that satisfies a dielectric strength voltage of AC 1.5 kV
Satisfies the standard of N S interface and PCMC
IA 2.0 A pulse transformer with a mounting area of 12.7 mm x 11 mm that satisfies the required height of 2.8 mm or less for an interface PC card compatible with Type I, and a small whole that is not resin-molded is manufactured by the following method. did.

By a liquid quenching method using a single roll, the composition was Fe74 Cu1 Nb3 Si17 B5, 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 1 mm wide ribbon.
Using the amorphous soft magnetic alloy ribbon having a width of 1 mm, an outer diameter of 8 mm in which a space factor K represented by Ae / A which is a ratio of an apparent cross-sectional area A and an effective cross-sectional area Ae of a wound core is changed. Eight toroidal winding cores having an inner diameter of 4 mm and a height of 1 mm were produced.

Here, the dimensions of the wound core are determined as described above, because the dimensions of the completed pulse transformer are determined by PCMCIA.
2.0 The height is 2.8 mm or less and the mounting area is 12.7 mm × 12.7 mm, which is necessary for mounting on an interface PC card compatible with Type I.

Next, these eight amorphous wound cores were
After heat treatment for 1 hour in a nitrogen atmosphere at ℃, slowly cooled, and then waited for the temperature of the wound core to reach room temperature, then insulated the surface of the wound core with epoxy resin, and compared with Invention 1 to Invention 4. The wound cores of Examples 1 to 4 were obtained.

The above amorphous soft magnetic alloy ribbon was 550
The soft magnetic alloy ribbon obtained by heat-treating in a nitrogen atmosphere at a temperature of 1 ° C. for 1 hour and then slowly cooled has a saturation magnetostriction constant λs in which 90% or more of the entire structure is occupied by fine crystals having a crystal grain size of 50 nm or less. is + 0.3 × 10 ^- it was ^6.

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

[0035]

[Table 1]

Using the nine magnetic cores, a pulse transformer was manufactured in the same manner as described in detail below. A winding 2 and a winding 3 each made of a polyurethane-coated electric wire (first type UEW) having a wire diameter of 0.05 mm are attached to a magnetic core 1 whose surface is insulated with epoxy as shown in FIG. The pulse transformer as shown in FIG. 1B is formed by winding the bifilar by the described number of turns.

The number of windings of each transformer in Table 2 is as follows: ambient temperature 20 ° C., frequency 20 kHz, magnetic field strength 0.05 A /
The minimum integer value at which the inductance at m was 23.9 mH or more was selected. The value of this inductance is
This is 1.2 times the inductance value of 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. 1B to a predetermined length, soldering is performed, and a 12.7 mm having a surface mounting lead terminal 4 is provided.
Then, each of the windings 2 and 3 is soldered to a predetermined position of the surface mounting lead terminal 4 as shown in FIG. 1C.

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

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

[0041]

[Table 2]

In Table 2, when the impedance characteristic is larger than the impedance shown in the DSU impedance template of FIG. 8.6 and the TE impedance template in FIG.

The transmission characteristics were evaluated as ○ when the electrical characteristics described on pages 37 to 55 of the above document 1 were satisfied using a Motorola ISDN terminal device IC, MC145474.

The insulation characteristics were evaluated by applying a voltage of 1.5 kV AC between the windings and between the windings and the case for 1 minute to determine whether or not insulation breakdown occurred. The sample that had been subjected to dielectric breakdown was evaluated 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 the present embodiment, it is not possible to satisfy the dielectric breakdown voltage of 1.5 kV. Was.

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

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

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

Further, it was confirmed that if the operating temperature range of the IC for terminal DN, MC145474 used for evaluating the transmission characteristics was expanded, the transmission characteristics could be sufficiently satisfied even in a wide temperature range from -40 ° C to 85 ° C. .

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

(Embodiment 2) A PC that satisfies the S-interface standard of ISDN that satisfies the insulation withstand voltage AC4 kV.
MCIA 2.0 Type I interface PC
A pulse transformer that satisfies the height required for the card of 2.8 mm or less, has a mounting area of 12.7 mm × 11 mm, and is small and entirely resin-molded is manufactured by the following method.

By a liquid quenching method using a single roll, the composition was Fe74 Cu1 Nb3 Si17 B5, the thickness t was 17 μm, and the width was 2
After producing a 5.4 mm amorphous soft magnetic alloy ribbon, the amorphous soft magnetic alloy ribbon was slit to obtain a 1 mm wide ribbon.
Using the amorphous soft magnetic alloy ribbon having a width of 1 mm, an outer diameter of 8 mm in which a space factor K represented by Ae / A which is a ratio of an apparent cross-sectional area A and an effective cross-sectional area Ae of a wound core is changed. Eight toroidal winding cores having an inner diameter of 4 mm and a height of 1 mm were produced.

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

Next, these eight amorphous wound cores are
After heat-treating in a nitrogen atmosphere at 1 ° C. for 1 hour and then gradually cooling, the surface of the wound core was insulated with epoxy resin after the temperature of the wound core reached room temperature.
~ A wound core of Comparative Example 9 was obtained.

In addition, 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 of
In the state where fine crystals having a diameter of not more than nm occupy, the saturation magnetostriction constant λs was + 0.3 × 10 ⁻⁶ .

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

[0057]

[Table 3]

Using the nine magnetic cores, a pulse transformer was manufactured in the same manner as described in detail below. A winding 12 made of a 0.05 mm-diameter polyurethane-coated electric wire (first type UEW) is wound on a magnetic core 11 whose surface is insulated with epoxy as shown in FIG. 2B to form a coil as shown in FIG.

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

After inserting a silicon glass tube 13 of a predetermined length into both ends of the winding 12 of the coil shown in FIG. 2B, the surface of the coil is epoxied as shown in FIG. 2C. Insulate coating.

A coil 14 of a 0.05 mm-diameter polyurethane-coated electric wire (1st class UEW) is shown in Table 4 for each magnetic core on a coil shown in FIG. The number of turns is equal to form a pulse transformer as shown in FIG.

After cutting both ends of the windings 12 and 14 shown in FIG. 2D to a predetermined length, soldering is performed, and a phenol resin case 16 having surface mounting lead terminals 15 is provided.
Then, both ends of the windings 12 and 14 are soldered to predetermined positions of the surface mounting lead terminals 15 as shown in FIG.

The inside of the phenol resin case 16 in which the pulse transformer shown in FIG. 2E is inserted is filled with urethane resin and then cured to form a resin-molded pulse transformer as shown in FIG. 2F.

The mounting area of this pulse transformer is 12.7 m.
mx 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 characteristic is indicated by a circle when the impedance is larger than the impedance shown by the DSU impedance template in FIG. 8.6 of the document 1 and the TE impedance template in FIG. 8.7.

The transmission characteristics were evaluated as ○ when the electrical characteristics described on pages 37 to 55 of the above document 1 were satisfied using a Motorola ISDN terminal device MC145474.

The insulation characteristics were examined by applying a predetermined voltage for 1 minute between the windings and between the magnetic core and the windings to determine whether or not dielectric breakdown occurred. Those having a withstand voltage of AC4kV are rated as ○, and those with a withstand voltage of AC1.5kV are satisfied.
Those that did not satisfy the withstand voltage of V were rated Δ, and those that satisfied the withstand voltage of 0.5 kV AC but did not satisfy the withstand voltage of 1.5 kV AC.

As can be seen from Table 4, 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 is not possible to satisfy the dielectric breakdown voltage AC4 kV.

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

The temperature around the wound core after insulation coating is 20 ° C., the frequency is 20 kHz, and the magnetic field strength is 0.0.
The effective AC ratio initial permeability K · μri at 5 A / m is 500
In order to achieve a value of at least 00, a crystal grain size of 5
Saturation magnetostriction constant λ of a soft magnetic alloy ribbon occupying at least 50% or more of fine crystal grains of 0 nm or less in the entire volume of the structure.
An occupancy ratio in which the absolute value of s is 1.0 × 10 ⁻⁶ or less and the ratio of the average thickness t of the soft magnetic alloy ribbon to the apparent core area A excluding the insulating coating portion and the effective area Ae. K is t /
It has also been found that it must be in the range of (t + 5) ≦ K ≦ t / (t + 2).

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

Further, it was confirmed that if the operating temperature range of the IC for terminal DN, MC145474 used for evaluating the transmission characteristics was expanded, the transmission characteristics could be sufficiently satisfied even in a wide temperature range from -40 ° C to 85 ° C. .

As a result of further detailed examination, it was found that the pulse transformer having a resin-molded structure in the entire range of -40 ° C. to 85 ° C. satisfied the characteristics defined by the ISDN S interface. It was also found that the temperature change of 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 small, high-performance pulse transformer that can be used for NS Net 64 "IC cards with a mounting area of 12.7 mm x 12.7 mm or less, a height of 2.8 mm or less, and can satisfy even the strictest European safety standards among safety standards. Obtainable.

In the above description, “INS net 6
Although the effectiveness of the present invention has been described using an example of a pulse transformer for an IC card, which requires the smallest mounting area and a thinner one among those for 4 ", a pulse transformer for an exchange or a telephone, or the aforementioned" Needless to say, it is effective for achieving both miniaturization and high performance of the pulse transformer other than this application, which is used in the same frequency band as the pulse transformer for the INS net 64 ″.

[Brief description of the drawings]

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

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

[Explanation of symbols]

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

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-94609 (JP, A) JP-A-63-239906 (JP, A) JP-A-7-45440 (JP, A) 139519 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01F 27/24-27/26

Claims (7)

(57) [Claims] 1. An average plate thickness tμ manufactured by a liquid quenching method.
m, and after winding an amorphous soft magnetic alloy ribbon having a width H of 0.5 mm ≦ H ≦ 3 mm, fine crystal grains with a crystal grain size of 50 nm or less occupy at least 50% or more of the entire structure volume. The absolute value of the saturation magnetostriction constant λs after heat treatment is 1.0
The space factor K expressed by Ae / A, which is the ratio of the apparent core cross-sectional area A to the effective cross-sectional area Ae, excluding the insulating coating portion, in a wound core having an insulating coating on the surface of the wound core of 10 ⁶ or less. Is t / (t + 5) ≦ K ≦ t / (t + 2),
Ambient temperature 20 ° C, frequency 20kHz, magnetic field strength 0.0
The effective AC ratio initial permeability K · μri expressed by the product of the AC ratio initial permeability μri and the space factor K at 5 A / m is 5000
0 or more, and a temperature change of the effective AC ratio initial permeability K · μri within a range of −40 ° C. to 85 ° C. ±
A wound core within 20%. 2. The wound 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.
/ M when the effective AC ratio initial magnetic permeability K · μri expressed by the product of the AC ratio initial magnetic permeability μri and the space factor K is 50,000 or more and the ambient temperature is in the range of −40 ° C. to 85 ° C. The temperature change of the effective AC ratio initial permeability K · μri is ± 1.
Wound core within 0%. 3. The wound core according to claim 1, wherein the surface of the wound core is epoxy, nylon,
An insulating coating of either polyimide or parylene, or at least one of these
A wound core having a multi-layer insulating coating containing at least one kind. 4. A pulse transformer comprising the wound magnetic core according to claim 1. 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 any one of epoxy, nylon, polyimide and parylene. A pulse transformer comprising an insulating coating or a multilayer insulating coating containing at least one of these. 7. An interface P using the pulse transformer according to claim 4. Description:
C card.