JPH02110909A - Laminated inductor and its inductance adjusting method - Google Patents

Abstract

PURPOSE:To prevent the deterioration in characteristics when large input is applied, and to make it possible to obtain stabilized characteristics in a variable range by a method wherein a conductive pattern is constituted with two conductive patterns which circulate alternately superposing in the direction of lamination through the intermediary of a magnetic layer, one end each of said conductive patterns are connected, and other end parts are connected to a DC bias current source. CONSTITUTION:In a laminated inductor provided with conductive patterns 21 and 22 which circulate superposing in the direction of lamination and other end parts of the conductive patterns are linking between magnetic layers 20, said two conductive patterns 21 and 22 are constituted by the two conductive patterns which circulate alternately superposing in the direction of lamination through the intermediary of the magnetic layers 20, one end each of said two conductive patterns 21 and 22 are connected, other end parts are connected to a DC bias current source. For example, a ferrite magnetic material 20 is laminated, and the conductive patterns 21 and 22 of silver, paradium and the like are formed inside the magnetic material 20 in such a manner that they circulate in the same direction superposing alternately in the direction of lamination while between the magnetic materials are being connected. A DC bias current is applied in reverse direction to the conductive patterns 21 and 22, and inductance is changed by this current.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laminated inductor, particularly a current-controlled laminated inductor whose inductance is made variable by a bias current, and a method for adjusting the inductance.

[Prior art]

With the demand for smaller, thinner electronic components, etc., multilayer inductors, in which a conductor batten is integrally formed within a magnetic ceramic, are being used in the field of inductors.

When printing or laminating green sheets and firing them, the inductance value remains constant, so in order to adjust the inductance value, it is necessary to trim the magnetic layer or form a recess in the magnetic material and insert the magnetic core. Methods to do so are being considered.

However, mechanical processing is required, fine adjustment is difficult, and there are problems in terms of reliability.

Therefore, the inventors proposed a current-controlled multilayer inductor in Japanese Patent Application No. 63-232867. As shown in FIG. 6, this is achieved by forming a conductor pattern 61 that will become the main winding and a conductor pattern 62 that will become the control winding in close proximity in the magnetic layer 60, and applying a DC bias to the conductor pattern 62. The magnetic field around the conductor pattern 61 is changed by the current, and the inductance value is changed. usually,
It operates to reduce inductance by increasing the direct current.

〔assignment〕

In the current-controlled multilayer inductor as described above, as the DC bias current increases, the magnetic core approaches saturation, the effective magnetic permeability decreases, and the inductance decreases. However, at the point where saturation begins, when the input is large, the effective value of the inductance changes between the positive half cycle and the negative half cycle, causing distortion in the output waveform.

The present invention aims to prevent such deterioration of characteristics and obtain stable characteristics within a variable range.

[Means to solve the problem]

The present invention solves the above problems with a structure and method that can increase the inductance as the bias current increases without using the saturation of the main magnetic path.

That is, in a laminated inductor including a conductor pattern that is connected at its end between magnetic layers and circulates in an overlapping manner in the lamination direction, the conductor patterns alternately overlap and circulate in the lamination direction via the magnetic layers. It is characterized in that it consists of two conductor patterns, one ends of which are connected to each other, and the other end connected to a DC bias current source.

Further, in a method for adjusting the inductance of a laminated inductor that includes a conductor pattern that is connected at the end between magnetic layers and circulates in a superimposed manner in the lamination direction, the conductor patterns are alternately superimposed in the lamination direction via the magnetic layers. two conductor patterns circulating in the same direction, and by applying direct current bias currents in opposite directions to the two conductor patterns, the magnetic resistance between the conductor patterns is changed, thereby changing the inductance. It has particular characteristics.

If you replace the conductor patterns with a magnetic layer with high permeability,
It becomes possible to vary over a wider range.

[Effect]

When a DC bias current in the opposite direction is applied between adjacent conductor patterns, the direction of the magnetic flux around the conductor patterns becomes opposite. Therefore, the magnetic flux leakage becomes additive,
Magnetic resistance becomes smaller. Therefore, the leakage magnetic flux of the inductor increases, and the inductance value also decreases.

When the DC bias current is increased, magnetic saturation occurs between the conductor patterns, and the effective magnetic permeability decreases, so the magnetic resistance increases and the magnetic flux in the main magnetic path increases accordingly. As a result, the inductance value becomes high.

Figure 1 is an explanatory diagram of the principle, which is variable in the range from the minimum value (L MIN ) at which no DC bias is applied to the maximum value (L MAX ) at which the magnetic path between the conductor patterns is saturated. . Instead of varying the main magnetic path when it is saturated, which is the case in the past, it is made to vary when the main magnetic path is unsaturated.

〔Example〕

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

FIG. 2 is a front sectional view showing an embodiment of the present invention. A magnetic material 20 of ferrite is laminated, and conductive patterns 21 and 22 made of silver-palladium or the like are formed inside the magnetic material 20 so that the magnetic material layers are alternately overlapped in the laminating direction and circulate in the same direction while being connected between the magnetic material layers. It is formed. As a result, conductive patterns 21 and 22 are formed in the magnetic layer 20.
is formed, resulting in a closed magnetic circuit type inductor.

DC bias currents are applied to the conductor pattern 21 and the conductor pattern 22 in opposite directions. Therefore, one end is connected and the other two ends are connected to a DC bias source. As a result, DC bias currents in opposite directions are applied to adjacent conductor patterns.

The magnetic fluxes generated in adjacent conductor patterns are in opposite directions. When the DC bias current is small and the magnetic path does not saturate, magnetic fluxes generated in adjacent conductive patterns pass between the conductive patterns in the same direction, and magnetic resistance is small. Therefore, the magnetic flux generated in the conductor patterns 21 and 22 does not pass through the main magnetic path φ, but instead passes through the magnetic paths Φ1 and Φ2 between the conductor patterns 21 and 22.
More things pass through. That is, leakage magnetic flux increases and inductance decreases. This is the state of L MIN shown in FIG.

When the DC bias current is gradually increased, the magnetic layer 25
The magnetic reluctance of increases gradually. That is, the leakage magnetic flux decreases, and the magnetic flux in the main magnetic path Φ increases. Magnetic path Φ8, φ
2 becomes saturated and the effective permeability becomes small, resulting in the state of L MAX shown in FIG.

FIG. 3 is a front sectional view showing another embodiment of the present invention, in which the space between conductor patterns 31 and 32 is replaced with a magnetic material 35 having a higher permeability than the magnetic material layer 30 and laminated. Since the magnetic permeability between the conductor patterns is high, the initial magnetic resistance can be made smaller, making it easier to control a small inductance value.

FIGS. 4 and 5 are circuit diagrams showing examples of the use of the laminated inductor according to the present invention. In the circuit arrangement of FIG. 4, the sum of the inductances of the two conductor patterns is obtained as an output, but in the example of FIG. 5, the conductor pattern indicated by the broken line is used only for control purposes.

〔effect〕

According to the present invention, the inductance can be changed by the bias current while the main magnetic path is not saturated. Therefore, a multilayer inductor with good characteristics can be replaced without causing distortion in the output waveform.

In particular, it becomes easy to vary the inductance minutely, and a laminated inductor suitable for use in a high frequency region etc. can be obtained.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the characteristics of the multilayer inductor according to the present invention,
Figures 2 and 3 are front sectional views of embodiments of the present invention, Figures 4 and 5 are circuit diagrams showing examples of its use, and Figure 6 is a front sectional view of a conventional current-controlled laminated inductor. be. 20.30...Magnetic layer 21.22.31.32...Conductor pattern No.
1 Figure 2

Claims (4)

[Claims] (1) In a laminated inductor that includes a conductor pattern that circulates between magnetic layers with their ends connected and superimposed in the lamination direction, the conductor patterns alternately overlap and circulate in the lamination direction via the magnetic layers. 1. A laminated inductor comprising two conductor patterns, one end of which is connected to the other, and the other end connected to a DC bias current source. (2) The laminated inductor according to claim 1, wherein at least a portion between the conductor patterns is replaced with a magnetic material having higher magnetic permeability than the magnetic material layer. (3) In a method for adjusting the inductance of a laminated inductor comprising a conductor pattern that is connected at its ends and circulates around the magnetic layers in an overlapping manner in the lamination direction, the conductor patterns are alternately arranged in the lamination direction via the magnetic layers. Two conductor patterns are superimposed and circulate in the same direction, and by applying DC bias current in opposite directions to the two conductor patterns, the magnetic resistance between the conductor patterns is changed, thereby changing the inductance. A method for adjusting the inductance of a multilayer inductor, characterized by: (4) Claim 3, wherein the ends of the two conductor patterns are connected to each other, and the other two ends are connected to a DC bias current source.
Method for adjusting the inductance of a laminated inductor as described in .