JPH07307225A - Magnetic thin film transformer - Google Patents

Abstract

PURPOSE:To improve inductance, realize the excellent high frequency characteristics and, further, suppress the noise. CONSTITUTION:A primary side coil unit 1 has a primary thin film core 4, a primary electrical insulating film 5 which covers the circumference of the thin film core 4 except its both end parts and a primary conductor coil 6 which is wound around the insulating film 5. A secondary side coil unit 2 has a secondary thin film core 7, a secondary electrical insulating film 8 which covers the circumference of the thin film core 7 except its both end parts and a secondary conductor coil 9 which is wound around the insulating film 8. Magnetic pieces 10 are fixed to both ends of an electrical insulating thin plate 3 respectively. Both end parts of the primary thin film core 4 and the secondary thin film core 7 are brought into contact with the magnetic pieces 10 respectively to form a closed magnetic circuit. It is to be noted that both end parts of the primary thin film core 4 and the secondary thin film core 7 may be directly brought into contact with each other by folding them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic thin film transformer having a magnetic thin film.

[0002]

2. Description of the Related Art As a conventional magnetic thin film transformer, the one shown in FIG. 2 is known. This magnetic thin film transformer is described in "All About Micro Magnetic Devices", a manual for magnetic devices (published by Kogyo Kenkyukai, October 1992, p. 14).
7).

The magnetic thin film transformer shown in FIG.
1, an electric insulating film 102 that covers the periphery of the thin film magnetic core 101, and a primary conductor coil 103 and a secondary conductor coil 104 that are alternately wound around the electric insulating film 102.
And are fixed to the substrate 105. The direction of the main component of the magnetic field lines generated by the primary current flowing through the primary conductor coil 103 is indicated by arrow 106. A secondary current is generated in the secondary conductor coil due to the interlinkage between the magnetic field lines generated by the primary current flowing in the primary conductor coil 103 and the secondary conductor coil.

[0004]

However, in the conventional magnetic thin film transformer, since the thin film magnetic core 101 has a rectangular shape and both ends thereof are located at both ends of the magnetic thin film transformer, the primary current magnetic field lines generated by the primary current. As a result, a demagnetizing field is generated in the thin film magnetic core 101 due to magnetization, and the density of the magnetic flux generated by the primary current decreases. Further, in the conventional magnetic thin film transformer, since the primary conductor coil 103 and the secondary conductor coil 104 are adjacent to each other, the magnetic force lines generated by the one-turn primary conductor coil 103 are adjacent to the secondary conductor coil 104. It does not interlink with the secondary conductor coil 104 that is farther away. Due to these causes, the conventional magnetic thin film transformer has a problem that the inductance becomes small.

Further, in the conventional magnetic thin film transformer, since the thin film magnetic core 101 does not have magnetic anisotropy in a specific direction, magnetization of the thin film at high frequency involves both domain wall movement and magnetization rotation. There is a problem that the permeability decreases at a high frequency, the inductance at a high frequency of the transformer decreases, and a large amount of Barkhausen noise is generated due to the domain wall motion.

An object of the present invention is to provide a magnetic thin film transformer capable of improving inductance.

Another object of the present invention is to provide a magnetic thin film transformer having excellent high frequency characteristics and capable of reducing noise.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a primary coil portion, a secondary coil portion opposed to the primary coil portion, and these primary coil portions. An electrical insulating thin plate disposed between the secondary coil portion and the primary coil portion, wherein the primary coil portion covers a primary thin film magnetic core and a peripheral portion of the primary thin film magnetic core excluding both ends thereof. And a primary conductor coil wound around the primary electrical insulating film, wherein the secondary coil portion covers a secondary thin film magnetic core and a peripheral portion except both ends of the secondary thin film magnetic core. A secondary electrical insulating film, and a secondary conductor coil wound around the secondary electrical insulating film, and both ends of the primary thin film magnetic core and the secondary thin film magnetic core are in contact with each other. It is characterized in that a closed magnetic circuit is formed.

Further, according to the present invention, in the magnetic thin film transformer, the primary and secondary thin film magnetic cores are formed such that a hard axis of magnetization is parallel to a magnetic force line generated by a current flowing through the primary conductor coil. Is characterized by.

[0010]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is an exploded perspective view showing an embodiment of the present invention. As shown in FIG. 1, a magnetic thin film transformer according to the present invention includes a primary side coil section 1, a secondary side coil section 2 arranged to face the primary side coil section 1, the primary side coil section 1 and the secondary side coil section. And an electrically insulating thin plate 3 arranged between the part 2 and the part 2.

The primary side coil portion 1 includes a primary thin film magnetic core 4
And a primary electrical insulating film 5 covering the peripheral portion of the primary thin film magnetic core 4 excluding both ends thereof, and a primary conductor coil 6 wound around the primary electrical insulating film 5. The secondary coil portion 2 includes a secondary thin film magnetic core 7, a secondary electric insulating film 8 covering the peripheral portion of the secondary thin film magnetic core 7 excluding both ends thereof, and a secondary electric insulating film 8 surrounding the secondary electric insulating film 8. It has the wound secondary conductor coil 9.

Magnetic pieces 10 are fixed to both ends of the electrically insulating thin plate 3, respectively. Both ends of the primary thin film magnetic core 4 and the secondary thin film magnetic core 7 are in contact with the magnetic pieces 10 to form closed magnetic paths. Both ends of the primary thin film magnetic core 4 and the secondary thin film magnetic core 7 may be bent to directly contact each other.

The primary thin film magnetic core 4, the secondary thin film magnetic core 7 and the magnetic piece 10 are arranged such that the hard magnetization axis is parallel to the magnetic field lines generated by the current flowing through the primary conductor coil 6.
That is, the primary thin film magnetic core 4 and the secondary thin film magnetic core 7 are formed in the direction of arrow 11 parallel to the long sides, and the easy axis of magnetization is formed in the direction of arrow 12.

The primary coil portion 1 is an electrically insulating thin plate 1.
It is fixed to the substrate 14 via 3. The secondary coil portion 2 is covered with an electrically insulating thin plate 15.

The substrate 14 is made of borosilicate glass. The primary thin film magnetic core 4, the secondary thin film magnetic core 7 and the magnetic piece 10 are the same as those described in R.M. C formed by F sputtering device
It is an amorphous film of oNbZr, and by applying a magnetic field in the direction parallel to the short sides of the primary and secondary thin film magnetic cores of the rectangular coil during sputtering, the easy axis of magnetization 12 is formed in this direction.
Is formed, and the hard axis 11 is formed in the direction orthogonal to the above. For example, the primary thin film magnetic core 4 and the secondary thin film magnetic core 7 are formed to a thickness of 6 μm, the magnetic piece 10 is formed to a thickness of 16 μm, and the relative magnetic permeability at 10 MHz is 1000 or more on the hard axis. Is.

The primary and secondary electrical insulating films 5 and 8 and the electrical insulating thin plates 13 and 15 are formed of SiO ₂ to a thickness of 1 μm. Said primary and secondary conductor coils 6,9
Is made of Cu to a thickness of 8 μm and has a coil width of 20 μm.
0 μm, the coil spacing is 100 μm, the number of turns is 5, and the size of the entire transformer is 3 mm × 2 mm × 1
mm.

At 10 MHz, the inductance is 200 nanohenries in the conventional magnetic thin film transformer of FIG. 2, whereas it is 380 nanohenries in the embodiment of the present invention. The coupling coefficient was 0.3 at 10 MHz in the conventional magnetic thin film transformer of FIG. 2, whereas it was 0.8 or more in the example of the present invention. Regarding the high frequency characteristics, the inductance was 150 nanohenries in the conventional magnetic thin film transformer of FIG. 2 at 500 MHz, whereas it was 350 nanohenries in the embodiment of the present invention.

The primary thin film magnetic core 4, the secondary thin film magnetic core 7 and the magnetic piece 10 are made of, for example, Fe, Co or Ni.
It may be formed of a system amorphous film or a Fe, Co or Ni system microcrystalline film. The primary and secondary electrical insulation films 5 and 8
The electrically insulating thin plates 13 and 15 may be made of AlN or Al ₂ O ₃ . Said primary and secondary conductor coils 6,9
May be formed of Al.

[0020]

The magnetic thin film transformer of the present invention can improve the inductance. Further, another magnetic thin film transformer of the present invention has excellent high frequency characteristics and can reduce noise.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a conventional magnetic thin film transformer with a part cut away.

[Explanation of symbols]

 1 primary side coil part 2 secondary side coil part 3 electrical insulating thin plate 4 primary thin film magnetic core 5 primary electrical insulating film 6 primary conductor coil 7 secondary thin film magnetic core 8 secondary electrical insulating film 9 secondary conductive coil 10 magnetic piece 13, 15 Electrically insulating thin plate 14 Substrate

Claims (3)

[Claims] 1. A primary side coil portion, a secondary side coil portion arranged to face the primary side coil portion, and an electrically insulating thin plate arranged between the primary side coil portion and the secondary side coil portion. The primary side coil portion includes a primary thin film magnetic core, a primary electrical insulating film that covers a peripheral portion of the primary thin film magnetic core except both ends thereof, and a primary conductor coil wound around the primary electrical insulating film. And a secondary side coil portion, a secondary thin film magnetic core, a secondary electric insulating film that covers the peripheral portion of the secondary thin film magnetic core except for both ends, and around the secondary electric insulating film. A magnetic thin film transformer comprising a wound secondary conductor coil, wherein both ends of the primary thin film magnetic core and the secondary thin film magnetic core are in contact with each other to form a closed magnetic circuit. 2. The magnetic thin film transformer according to claim 1, wherein both ends of the primary thin film magnetic core and the secondary thin film magnetic core are in contact with each other through magnetic pieces to form a closed magnetic circuit. Magnetic thin film transformer. 3. The magnetic thin film transformer according to claim 1, wherein the primary and secondary thin film magnetic cores are formed such that axes of hard magnetization are parallel to magnetic lines of force generated by a current flowing through the primary conductor coil. A magnetic thin film transformer characterized in that