JPH03188607A - Transformer - Google Patents

Abstract

PURPOSE:To obtain a transformer, which can be miniaturized and integrated and has the high transformation efficiency of high-frequency power, by installing a primary coil and a secondary coil onto the same plane and using a magnetic core in which insulating thin-films and magnetic thin-films are laminated alternately. CONSTITUTION:A magnetic layer 8 is sputtered onto a non-magnetic insulating substrate 7, an insulating layer 9 is vapor-growth, and the pattern of a conductive thin-film having a shape that a zigzag shape and a spiral shape are combined is formed onto the insulating layer 9. Current is made to flow through a terminal 4 from the terminal 3 of a plate coil 1. The current the coil 1 form a flow 13 of magnetic flux. The flow 13 of magnetic flux does not go to the outside by magnetic layers 7 and 12, and is interlinked with a coil 2 and flows. When AC current is made to flow through the coil 1, voltage is generated in the coil 2 by interlinking magnetic flux. According to the constitution, the transformation characteristics of high-frequency power incapable of being transformed owing to eddy current loss in a conventional transformer is improved, and the magnetic layers wrap the coil, thus also resisting noises from the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a planar transformer suitable for use in high-frequency pulse transformers, power supply circuits in integrated circuits, and the like.

[Conventional technology]

As a conventional technique, there is a thin transformer described in Japanese Unexamined Patent Publication No. 169315/1983. FIG. 4(a) Perspective view,
As shown in FIG. 4(a), a sectional view of which is shown in FIG. 4(b), a thin transformer is constituted by a magnetic core 17, a bobbin 16, a primary winding, and a secondary winding 18.

- The secondary winding 18 is wound around the bobbin 16 and connected to the terminal 19, and the magnetic core 1 is connected to the hole in the center of the bobbin 16.
7 is connected by mechanical compression or adhesive, as shown in Fig. 5(b).
As shown in the figure, a magnetic core 17 is arranged around a winding 18 to form a magnetic circuit.

[Problem to be solved by the invention]

However, with conventional thin transformers, it is impossible to integrate them together with semiconductor elements on a substrate. Furthermore, when attempting to construct a transformer using winding wire, the configuration becomes complicated, such as passing a magnetic core through a central hole, making it difficult to manufacture.Furthermore, due to the structure of the transformer, the conventional thin transformer cannot be used in high frequency bands. are unsuitable for power and signal transmission due to eddy current losses.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a small-sized transformer that can be integrated into a small size, has a simple manufacturing process, and has high conversion efficiency for high-frequency power.

[Means to solve the problem]

In order to solve the above problems, the transformer of the present invention includes a planar coil in which a primary coil and a secondary coil are formed on the same plane, and a magnetic core in which a number of magnetic layers are alternately laminated with insulating thin films and magnetic thin films. The magnetic circuit is characterized in that the insulating layer is a thin film to constitute the magnetic circuit.

[Effect]

According to the above structure of the present invention, since it has a thin film structure and is suitable for compact integration, it is possible to incorporate a stabilizing power supply, which was conventionally installed on a circuit board for voltage stabilization, into the integrated circuit. This improves the stability of the circuit operation of the integrated circuit.

In addition, since the magnetic material is used in a thin film state, the transformer is suitable for high-frequency power.

Furthermore, since the planar coil has the primary coil and secondary coil formed on the same plane, the manufacturing process is simplified.

〔Example〕

The present invention will be explained in detail based on the drawings.

FIG. 1 is a plan view (a) and a main sectional view (b) showing a transformer of the present invention. The transformer of the present invention has a planar coil 1
and a planar coil 2 and insulating layers 9 and 10 surrounding it.
．． 11 and magnetic layers 8 and 12.

The planar coil 1 and the planar coil 2 have a combination of meandering and spiral shapes. A zigzag is a comb-shaped tooth-like shape, and a spiral is a spiral shape. The planar coil 1 and the planar coil 2 have a shape in which the number of twists is 3 and the number of spirals is 2.

By forming the planar coil 1 and the planar coil 2 in a meandering shape, the transformation characteristics of high-frequency power having a frequency of IMHz or more can be improved due to the series effect of a small inductor.

This is due to the reduction in losses due to subdivision of the magnetic flux flow.

An increase in the number of spirals of the planar coils 1 and 2 increases the current density of the coils and increases the magnetomotive force, but the distance between the planar coils 1 and 2 increases.

In the case of the transformer of the present invention, since the planar coil 1 and the planar coil 2, which are a combination of the serpentine fold and the spiral, are constructed on the same plane, the manufacturing process can be simplified and integrated.

Next, the manufacturing process of the transformer of the present invention will be explained. First, a magnetic layer 8 is formed on a nonmagnetic insulating substrate 7 using a sputtering device or the like. An insulating layer 9 is formed on the magnetic N8 using a vapor phase growth apparatus (hereinafter abbreviated as CVD apparatus) or the like. The conductive thin film formed on this insulating layer 9 by a sputtering device or the like is a combination of a zigzag shape and a spiral shape, and the number of zigzag folds is three and the number of spirals is two. ) The planar coil 1 and the planar coil 2 are patterned into an interlocking shape by etching or the like. An insulating layer 10 that fills the unevenness of the planar coil 1 and the planar coil 2 is formed using a CVD device.The insulating layer 11 is formed on the flat surface of the insulating layer 10 using a CVD device or the like. A magnetic layer 12 is formed on the insulating layer 11 using a sputtering device or the like to constitute a transformer.

FIG. 2 is a schematic diagram illustrating the flow of magnetic flux using a cross-sectional view of the transformer of the present invention. When current flows into terminal 3 of planar coil 1 in FIG. 1(a), current flows out from terminal 4. At this time, the current in the planar coil 1 creates a magnetic flux flow 13 as shown in FIG. The magnetic flux flow 13 does not diverge to the outside due to the magnetic layer 7 and the magnetic layer 12, but flows interlinking with the planar coil 2. When an alternating current is passed through the planar coil 1, a voltage is generated in the planar coil 2 due to interlinkage magnetic flux, and it functions as a transformer.

FIG. 3 is a cross-sectional view of the magnetic layers 8 and 12 on the nonmagnetic insulating substrate 7 when they are formed using a sputtering device or the like. The eddy current loss due to high-frequency magnetic flux when the magnetic core of a transformer is made of a magnetic thin film is as shown in Sakurai (ed.): Magnetic Thin Film Engineering, Maruzen Co., Ltd. pp. 250-254. It is generally known that the thinner the thickness, the lower the loss. For this reason, as shown in FIG. 3, the magnetic layer 8 and the magnetic layer 12 are constructed by laminating the insulating thin film 15 and the magnetic thin film 14 alternately. In FIG. 3, the structure has four layers of magnetic thin film 14 and three layers of insulating thin film 150. The insulating thin film 15 is formed by oxidizing the surface of the magnetic thin film 14 or by depositing it using a CVD device or the like. For example, when Mo permalloy is used for the magnetic thin film 14, the skin depth without eddy current loss at a frequency of 10 MHz is 0.8 μm.
．． 8 μm or less, the insulating thin film 9 is made by reducing the surface of the Mo permalloy of the magnetic thin film 14 to 0.1 μm μm.
and an insulating thin film are laminated in two or more layers.

By laminating this magnetic thin film, high-frequency power with a frequency of about MHz or more can be efficiently transmitted.

〔Effect of the invention〕

According to the present invention, the film can be made thinner and smaller than the conventional thin transformer, and the manufacturing process can be simplified. Further, it has the effect of being able to transform high-frequency power, which cannot be transformed with conventional transformers due to eddy current loss, and positive characteristics.

Furthermore, since the planar transformer of the present invention has a structure in which the magnetic layer wraps around the coil, it serves as a magnetic shield and has the effect of being resistant to external noise.

[Brief explanation of drawings]

FIG. 1 is a plan view (a) and a main sectional view (b) showing a transformer of the present invention. FIG. 2 is a schematic diagram of the flow of magnetic flux in the transformer of the present invention. FIG. 3 is a diagram showing an example of a configuration diagram of the magnetic layer 8 and the magnetic layer 12. FIG. 4(a) is a perspective view of a conventional thin transformer. FIG. 4(b) is a sectional view of a conventional thin transformer. 1, 2... 3, 4. 5゜7 ・ ・ ・ ・ 8, 12・ ・ 9, 10. 1 13 ・ ・ ・ ・ 14 ・ ・ ・ ・ 15 ・ ・ ・ ・ 16 ・ ・ ・ ・ ・ Planar coil 6・Terminal・・Insulating substrate・・Magnetic layer 1・Insulating layer・・Magnetic flux flow・・Magnetic thin film・・Insulating thin film...Magnetic core 17...Bobbin 18...Winding 19...Terminal or higher

Claims (1)

[Claims] A magnetic circuit is constructed by a planar coil in which a primary coil and a secondary coil are formed on the same plane, a magnetic core in which the magnetic layer is made up of alternately laminated insulating thin films and magnetic thin films, and the insulating layer is a thin film. Trance to do.