JP2866796B2 - Pulse transformer for ISDN - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse transformer for ISDN.

[0002]

2. Description of the Related Art A pulse transformer for ISDN is 20 kHz.
It is necessary to guarantee a high inductance of 20 mH or more in z and to realize a low capacitance and a low leakage inductance. Conventionally, a ferrite core of a pot type, an EI type, an EE type, or the like is combined with a bobbin with a winding. Alternatively, the ring-shaped ferrite core is formed by winding. Alternatively, a winding core is formed by attaching an insulating case or an epoxy coating to a wound core formed by winding a Co-based amorphous.

[0003]

In recent years, a pulse transformer for ISDN has a minimum height of 5 mm or less, and actually has a height of 3.6 mm or 2.8 mm in order to be housed in an IC card.
Ultra-thin dimensions such as the following are required. Also, the card size is limited to 54 × 85.6 mm, and it is necessary to mount two transformers for drive and receive in this area. When an attempt is made to construct a pulse transformer for ISDN that can be accommodated in this IC card, a conventional ferrite core such as a pot type, EI type, or EE type has a magnetic permeability of at most 8000 to 10000, and a high inductance with a required size. In order to obtain the required number of turns, an enormous number of turns is required, resulting in an increase in leakage inductance or an increase in capacity. Therefore, it is extremely difficult and unrealistic to satisfy required characteristics. When a ring-shaped ferrite core is used, a magnetic permeability of about 15000 can be obtained at the maximum, but a large number of turns is still required. Assuming a trial calculation, μi = 15000 and O
When a ring-shaped ferrite core of R11-3-4H is used, at least 49 turns are required with a 0.05 mm wire, which is not a realistic specification. This calculation shows that μi = 15000MI
N. It is a stricter specification in consideration of the variation in characteristics, temperature characteristics, and the like. Further, an increase in the number of turns in the ring-shaped ferrite core causes the following problem. 1) Difficulty of work, increased cost. 2) The occurrence rate of interlayer insulation failure increases. 3) If the number of windings is one, the effect on the coil height is small. However, if the number of windings is two or three, the effect on the coil height is large and the production variation is large. 4) Increase in winding capacity. 5) Increase in leakage inductance. On the other hand, a Co-based amorphous core has a permeability of 10,000.
A very high value such as 0 can be obtained, but has the following disadvantages. 1) A general thin ring-shaped wound core has a core height of 3 mm.
It is difficult to manufacture a ribbon having a smaller width than this, and it is difficult to manufacture the ribbon and to wind up the core, which leads to an increase in cost. 2) When winding a ribbon having a width of 3 mm, the ribbon core is shifted, so that the magnetic core height varies up to a maximum of about 3.5 mm. Further, when the winding is performed on the ring-shaped magnetic core with one layer, an unnecessary space is formed at the center of the winding frame, which hinders miniaturization of the coil. Therefore, it has been extremely difficult to satisfy the required characteristics and required dimensions even with a conventional Co-based amorphous wound core. The above-described problems occur, and it has been practically impossible to satisfy both the height dimension and the required characteristics in the past. The present invention, in view of the above,
ISD that satisfies both height dimensions and required characteristics and is easy to produce
An object is to provide a pulse transformer for N.

[0004]

As a result of conducting research to solve the above-mentioned problems, it has been found that both the height and the required characteristics can be satisfied with the following configuration. The present invention has a plurality of pipe-shaped cores formed by winding an Fe-based ultra-microcrystalline soft magnetic alloy having a maximum thickness of 15 μm or less, and a storage space in which two or more pipe-shaped cores are disposed adjacent to each other. And a case having wiring terminals,
An IND pulse transformer comprising a winding passing through a through hole of an adjacent pipe-shaped magnetic core provided in the storage space, and connecting a lead wire of the winding to the wiring terminal. Further, the present invention has four pipe-shaped cores formed by winding an Fe-based ultra-microcrystalline soft magnetic alloy having a maximum thickness of 15 μm or less, and two pipe-shaped cores are arranged adjacent to each other. The pipe-shaped magnetic cores are respectively provided in the storage space of the case having the spaces in parallel and having the wiring terminals.
This is a pulse transformer for ISND in which two adjacent pipe-shaped magnetic cores are provided adjacent to each other, and a winding passing through a through hole is applied to each of two adjacent pipe-shaped cores, and a lead wire of the winding is connected to the wiring terminal. . Further, in the above structure, the winding disposed on the magnetic core in two adjacent two pipes is used as a drive transformer, and the winding disposed on the other adjacent two pipes in the magnetic core. Is a receiving transformer. The preferred dimensions of the magnetic core are an outer diameter of 4 mm or less and a length of 30 mm or less, and more preferably an outer diameter of 2.4 to 2.0 mm, an inner diameter of 1.3 to 1.7 mm, and a length of 1 mm.
0 to 30 mm. The magnetic core has a thickness of 15 mm.
It is preferable to provide insulation by coating in a coating of 0 μm or less or a case of 0.15 mm or less in thickness. In the present invention, it is preferable to use a material having μe = 30000 or more.

[0005]

According to the invention, a pipe-shaped magnetic core is provided.
With this pipe-shaped core, a high AL value can be obtained without increasing the outer diameter of the core, and the number of turns can be reduced. In addition, since the windings are formed by applying windings passing through the two through holes around the opposite side surfaces of the two pipe-shaped cores, the windings do not appear on the outer diameter of the cores, and the winding thickness is reduced. Height dimensions can be reduced. The outer diameter of the core is 4
If the length is 30 mm or less and the length is 30 mm or less, a coil that satisfies the characteristics sufficiently and can be mounted can be obtained. More preferably, when the outer diameter of the magnetic core is 2.4 to 2.0 mm, the inner diameter is 1.3 to 1.7 mm, and the length is 10 to 30 mm, the height of the pulse transformer is 2.8 mm. And a pulse transformer with sufficient characteristics can be obtained. The above dimensions are for the case of using an Fe-based ultra-microcrystalline soft magnetic alloy material, and it is difficult to satisfy the characteristics and dimensions using a conventional ferrite core. The reason is that, with ferrite, only μ = 15,000 can be obtained, the number of turns is required to be about 1.4 times that of the present invention, and the characteristics are not satisfied unless the magnetic core is increased. Needless to say, coating and enclosing the case are for insulation and protection of the magnetic core and insulation with the coil. Further, according to the present invention, since a case having a space for accommodating a pipe-shaped magnetic core is used, the winding operation is facilitated. For example, when a winding is applied to the through-holes of two pipe-shaped magnetic cores, if the magnetic core is twisted, the winding work is difficult to perform, and the coil height becomes higher than a predetermined dimension. Occur, but these are improved by the case of the present invention. Also,
The wiring terminals are located on the side parallel to the axial direction of the magnetic core, so the long side of the parts can be used, the wiring terminals can be easily laid out, and the actual wiring work can be set with a wide terminal interval, making it easy Becomes The reason why the thickness of the ribbon of the Fe-based ultra-microcrystalline soft magnetic alloy is limited to 15 μm or less is that the workability and the yield at the time of manufacturing the wound core are taken into consideration. That is, a typical amorphous ribbon has a thickness of 17 to 25.
μm, but the thicker the ribbon, the smaller the inner diameter of the magnetic core and the more difficult it is to wind up. The biggest problem that makes the winding difficult is breakage of the ribbon. Table 1 shows the experimental results of ribbon thickness and ribbon breakage. The ribbon thickness in Table 1 is the minimum thickness and the maximum thickness of each ribbon.
This is the number of breaks when the coil is wound 00 times.

[0006]

[Table 1]

[0007]

【Example】

Example 1 Using a ribbon of Fe-based ultrafine crystal material (FT-3 material manufactured by Hitachi Metals, Ltd.) (thickness: 15 μm, width: 15 mm), an outer diameter of 2.2 mm, an inner diameter of 1.5 mm, and a length of 15 mm were used. A pipe-shaped core was prepared and heat-treated at 570 ° C. for 1 hour in a nitrogen atmosphere. When the characteristics of this magnetic core were measured, μe =
30,000, AL value was 34 μH / N ＾ 2. An 80 μm thick parylene coating is applied to the magnetic core.
Using a 06φ wire, six parallel wires are wound 9 turns, and 1
A pulse transformer of the next 18 turns and the secondary 36 turns was used. FIG. 1 shows a perspective view of this embodiment. In FIG.
1 is a magnetic core, 2 is a winding, and 3 is a wire. When the inductance at 20 kHz of this example was measured, a sufficient inductance of 22.1 mH was obtained. FIG. 2 is a front view of a case in which the magnetic core is provided.
A back view is shown in FIG. The case 11 has a through-hole 12 into which the pipe-shaped magnetic core 1 (indicated by a broken line in the figure) is inserted, and a plurality of wiring terminals 13 are recessed on the side surface parallel to the axis of the through-hole 12. 15, a wiring groove 14 for passing a lead wire is formed between a portion where the through hole 12 is provided and a portion where the wiring terminal is provided. I have. A pipe-shaped magnetic core 1 is provided in a through hole 12 of
A pulse transformer was constructed. This property is as described above. In this embodiment, the winding state and the case are described separately for convenience of explanation.
Then, the above-mentioned pipe-shaped magnetic core 1 is inserted, and then the above-mentioned winding is performed.
The above-described pulse transformer is configured by connecting to the wiring terminal 13 of FIG.

Example 2 As in Example 1, a ribbon of FT-3 material (12 μm thick) was used.
m, width 15 mm) using an outer diameter of 2.2 mm and an inner diameter of 1.
A wound core having a length of 5 mm and a length of 15 mm was prepared and heat-treated at 570 ° C. for 1 hour in a nitrogen atmosphere. When the characteristics of this pipe-shaped magnetic core were measured, μe = 45000, AL value 5
1.1 μH / N ＾ 2. The thickness of this core is 80μm
Is applied, and 6 parallel wires are wound by 8 turns using a wire of 0.06φ, and the primary 16 turns, 2 turns
A pulse transformer of the next 32 turns was used. 2 of this embodiment
When the inductance at 0 kHz was measured,
A sufficient inductance of 6.2 mH was obtained. FIG. 4 is a front view of a case constituting the pulse transformer, and FIG. 5 is a rear view of the case. The case 21 has a through-hole 22 into which the above-mentioned pipe-shaped magnetic core 26 (shown by a broken line in the figure) is inserted, and a plurality of wiring terminals 23 are provided on the side surface parallel to the axis thereof. A wiring groove 24 for passing a lead wire is formed between a portion where the through hole 22 is provided and a portion where the wiring terminal 23 is provided. I have. The through hole 22 is formed in a shape into which two pipe-shaped magnetic cores 26 can be inserted adjacently, and two a and b are formed. The pulse transformer having the structure as shown in FIG. 1 was constructed for each of a and b, and a pulse transformer for ISDN was constructed with a used for driving and b used for receiving. In the present embodiment, the winding state and the case are separately described for the sake of explanation. In the present embodiment, the pipe-shaped core 26 is inserted into the case 21 and then the winding is performed. The above-described pulse transformer is configured by connecting the lead wires of the wires to the wiring terminals 23 of the case 21. Further, the shape of the through hole of the case into which the ring-shaped magnetic core is inserted is not limited to the above shape, and may be, for example, a shape as shown in FIGS. The winding may be inserted into the case after the core is wound. However, it is easier to perform the winding operation by inserting the core into the case and then winding the core. Since the position of the wiring terminal is provided on the side surface parallel to the axis of the through hole, a pipe-shaped magnetic core is used. Can be set widely, so that the actual wiring work becomes easy. Also, the through hole 2
The wiring groove 24 provided between the part where the wiring terminal 2 is provided and the part where the wiring terminal 23 is provided prevents unnecessary leakage inductance from being generated when the lead wire from the winding is extended for a long time. In order to suppress this, wiring is provided so that wiring can be performed in a concentrated manner. If there is no wiring groove, each lead wire is spread and wired, so that an air-core coil is formed, and this air-core coil causes leakage inductance.

Comparative Example 1 Ribbon of Fe-based ultrafine crystal material FT-3 (having a thickness of 17 μm)
m, width 1.5mm), outer diameter 10mm, inner diameter 4m
m and a height of 1.5 mm were prepared and heat-treated at 570 ° C. for 1 hour in a nitrogen atmosphere. When the characteristics of this magnetic core were measured, μe = 50000, AL value 12.8 μH /
N ＾ 2. This magnetic core is stored in a predetermined case, and
Using a 06φ wire, six parallel wires are wound 21 turns,
The pulse transformer had 42 turns of primary and 84 turns of secondary. FIG. 9 shows a perspective view of this comparative example. In FIG.
Reference numeral 91 denotes a magnetic core, 92 denotes a winding, and 93 denotes a wire. When the inductance at 20 kHz of this comparative example was measured, a sufficient inductance of 22.7 mH was obtained.

Comparative Example 2 Mn-Zn high permeability material (GP manufactured by Hitachi Ferrite Co., Ltd.)
-11)), outer diameter 2.2mm, inner diameter 1.5m
A pipe-shaped magnetic core having a length of m and a length of 15 mm was prepared. When the characteristics of this core were measured, μe = 10000, AL value 1
1.4 μH / N ＾ 2. The thickness of this core is 80μm
Was applied to a predetermined bobbin, and six parallel wires were wound using a 0.06φ wire rod as much as possible to obtain 10 turns. This was used as a transformer with 20 turns of primary and 40 turns of secondary. When the inductance of this transformer at 20 kHz was measured, only an insufficient inductance of 9.1 mH was obtained. Table 2 shows the dimensions, inductance, and number of coil turns of the above Examples and Comparative Examples.

[0011]

[Table 2]

From Table 2, it can be seen that in the example, the height did not exceed 2.8 mm, the inductance was satisfied, and the number of turns was small, but in Comparative Example 1, the height was 2.8 mm or less and the inductance was satisfied. However, the number of turns is remarkably large at 42 turns: 84 turns compared to 18 turns: 36 turns of the first embodiment, and it is clear that workability is poor. In Comparative Example 2 using ferrite, required characteristics could not be obtained. Further, in the above embodiment, the wire constituting the primary coil is colored in advance, and in the winding work and the terminal tying work,
Discrimination and work could be facilitated. Further, in the above embodiment, the coating is applied to the insulation of the pipe-shaped magnetic core.
It is desirable that the thickness be 0 μm or less. The insulating means is not limited to the coating, and a case may be used. In this case, the thickness of the case is 0.15 mm
It is desirable to make the following.

[0013]

As described above, according to the present invention, the ISDN
Therefore, the characteristics of the pulse transformer for use can be satisfied and the thickness can be reduced, and it is effective for simplifying the manufacturing method.

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment according to the present invention.

FIG. 2 is a front view of a case according to an embodiment of the present invention.

FIG. 3 is a rear view of the case according to the embodiment of the present invention.

FIG. 4 is a front view of a case according to another embodiment of the present invention.

FIG. 5 is a rear view of a case of another embodiment according to the present invention.

FIG. 6 is a front view of a case according to another embodiment of the present invention.

FIG. 7 is a front view of a case according to another embodiment of the present invention.

FIG. 8 is a front view of a case according to another embodiment of the present invention.

FIG. 9 is a perspective view of a comparative example according to the present invention.

[Explanation of symbols]

 1, 26 core 2 winding 3 wire 11, 21 case 12, 22 through-hole 13, 23 wiring terminal 14, 24 wiring groove 15, 25 recess

Claims (3)

(57) [Claims] 1. A plurality of pipe-shaped cores formed by winding an Fe-based ultra-microcrystalline soft magnetic alloy having a maximum thickness of 15 μm or less, and a storage space in which two or more pipe-shaped cores are disposed adjacent to each other. And a case having a wiring terminal, and a winding passing through a through hole of an adjacent pipe-shaped core provided in the storage space, and connecting a lead wire of the winding to the wiring terminal. A pulse transformer for ISND. 2. A storage having four pipe-shaped cores formed by winding an Fe-based ultra-microcrystalline soft magnetic alloy having a maximum thickness of 15 μm or less, wherein two pipe-shaped cores are arranged adjacent to each other. Two pipe-shaped cores are arranged adjacent to each other in the storage space of a case having a space in parallel and having a wiring terminal, and two adjacent pipe-shaped cores are respectively provided with through holes. And a lead wire of the winding is connected to the wiring terminal. 3. The drive core according to claim 2, wherein the winding disposed on the magnetic core in one adjacent two pipes is a drive transformer, and the core is formed on the other adjacent two pipes. A pulse transformer for ISDN, characterized in that the winding disposed in the transformer is a receiving transformer.