JPH06103323B2 - Current detector - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a current detector in which a magnetic detection element such as a Hall element or a magnetic resistance element and a coil are combined.

<Prior Art> FIGS. 5 and 6 show conventional examples of a current detector including a magnetic detection element and a coil.

In the first conventional example shown in FIG. 5, two winding type coils 21 each including a core 21c and a winding portion 21m are used, and these coils 21 and 21 are fixed in parallel on a base 22. A magnetic detection element 23 is provided at a magnetic field forming position on 21.

In the second conventional example shown in FIG. 6, a coil 24 in which a winding portion 24m is provided in a core 24c having a gap g like a C shape is used, and the magnetic detecting element 23 is provided in the vicinity of the gap g of the core 24c.
Is provided.

In both conventional examples, the circuit for current measurement is coil 21,2.
The magnetic detection element 23 is connected to the four windings, and the magnetic flux generated by the current flowing through the windings is detected.

<Problems to be Solved by the Invention> By the way, all conventional current detectors use a wire-wound coil. Since there is a limit to miniaturization of this wire-wound coil, there is a problem that miniaturization of the entire detector cannot be achieved to some extent.

Further, since the winding type coil has a winding process, the cost is high, and it is difficult to obtain an inexpensive product.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to make it possible to reduce the size of the entire detector and reduce the cost by making the coil portion a laminated type.

<Means for Solving the Problems> In order to achieve the above object, the present invention is a current detector including a magnetic detection element and a coil portion, wherein the coil portion includes a magnetic layer and a conductor pattern. And has a through hole, and the through hole penetrates the inside of the coil pattern constituted by the conductor pattern in the stacking direction, and the magnetic detection element is along the stacking direction of the coil portion. The structure is such that the end face is attached to a place that almost shields the through hole.

<Operation> In the above configuration, when a current flows from the circuit to be measured for current to the coil pattern constituted by the conductor pattern in the coil portion, an amount of magnetic flux corresponding to the magnitude of the current is generated in the through hole. . Since this magnetic flux penetrates the magnetic detecting element on the through hole, it is detected by the magnetic detecting element, and the magnitude of the current can be known from the detection signal.

<Examples> Hereinafter, the present invention will be described in detail based on Examples shown in the drawings.

1 to 3 relate to an embodiment of the present invention. FIG. 1 is an external perspective view, FIG. 2 is an exploded perspective view, and FIG. 3 is a longitudinal sectional view.

The current detector of this embodiment includes a magnetic detection element 1 and a coil section 2.

A Hall element or a magnetoresistive element is used as the magnetic detection element 1. 1a is the terminal.

The coil portion 2 is a laminated coil, and is composed of a laminated body of a plurality of magnetic layers and conductor patterns between them, as will be described later with reference to FIG. The mounting electrodes 4, ... For the magnetic detection element 1 are formed on the end face in the stacking direction (the upper face in the drawing).

As shown in FIG. 2, the coil portion 2 is formed by alternately laminating magnetic layers 5, ... And conductor patterns 6 ,. Inside the lamination, the end portions of the conductor patterns 6 of the respective layers are It is connected to the conductor pattern 6 of the other layer by the through hole 7 to form a coil pattern of several turns as a whole. Of these conductor patterns 6, ..., The conductor patterns 6, 6 of the uppermost layer and the lowermost layer have lead portions 6a, 6a, respectively, and are connected to the corresponding external electrodes 3, 3 through these lead portions 6a, 6a. ing.

A through hole 8 in the stacking direction is formed in the center of the coil portion 2. The through hole 8 penetrates the inside of the coil pattern formed by the conductor pattern 6.

In order to form the through hole 8, a hole may be formed in each of the molded sheets to be the magnetic layer 5 before the magnetic layer 5 and the conductor pattern 6 are laminated, or a magnetic body may be formed. After the layer 5 and the conductor pattern 6 are laminated and pressure bonded, the through hole 8 may be formed in the laminated body before firing, or the laminated body after firing may be cut to form the through hole 8. You may.

The magnetic detection element 1 is placed at a position that shields the through hole 8 at the end face (upper face) of the coil portion 2 in the stacking direction,
Each terminal 1a is connected and fixed to the mounting electrode 4.

In the above configuration, the circuit for measuring the current is connected to the coil unit 2
And the attachment electrode 4 on the upper surface of the coil portion 2 is connected to the detection signal processing circuit.

Here, when a current flows through the coil pattern in the coil portion 2 through the external electrode 3, a magnetic flux of an amount corresponding to the current value is generated in the through hole 8, and this magnetic flux is generated by the magnetic detection element 1 on the through hole 8. Penetrate through. As a result, the detection signal of the magnetic detection element 1 changes, and the current flowing in the coil pattern of the coil unit 2 is detected from this detection signal.

In the above-mentioned embodiment, the structure in which the conductor patterns 6 are connected to each other through the through hole 7 is shown as the internal structure of the coil portion 2. However, the internal structure of the coil portion 2 and its manufacturing method are limited to those in the above-mentioned embodiment. Instead, other internal structure or manufacturing method adopted in a general laminated coil may be adopted.

FIG. 4 shows a coil portion 12 manufactured by partial lamination. The coil portion 12 of this embodiment includes a plurality of magnetic layers 15
And a conductor pattern 16 between them, and has an external electrode (not shown in FIG. 4) on the side surface, a mounting electrode 14 on the end face in the stacking direction, and a through hole 18 in the stacking direction in appearance. Although there is no difference from the example of FIGS. 1 to 3 in the point, in the inside of the stacked layers, the intermediate magnetic layer 15 excluding the uppermost layer and the lowermost layer is formed.
Are partially laminated, and the conductor patterns 16 on these partial magnetic layers 15 are printed in a state of partially overlapping the conductor pattern 16 of the lower layer. Therefore, inside the coil portion 12, the conductor patterns 16 are directly connected to each other to form a coil pattern.

<Effects of the Invention> As described above, according to the present invention, since the coil portion is of the laminated type, the coil portion can be configured in a small size, and the detector can be compared with the conventional example using the wire wound coil. The overall size can be reduced.

Moreover, since the winding process in the wire-wound coil is not required, the cost can be reduced and the inexpensive current detector can be obtained.

Further, since the magnetic detection element is directly attached to the coil portion, the coil portion also serves as a support member for the magnetic detection element. From this point as well, not only the detector can be downsized but also the coil portion can be provided. The whole can be surface-mounted on a printed wiring board.

In addition, since most of the magnetic flux generated in the coil portion penetrates the magnetic detection element, there is an advantage that the detection sensitivity is good.

[Brief description of drawings]

1 to 3 relate to an embodiment of the present invention. FIG. 1 is an external perspective view, FIG. 2 is an exploded perspective view, FIG. 3 is a vertical sectional view, and FIG. 4 is another embodiment. It is an exploded perspective view of an example coil part. 5 and 6 are perspective views of a conventional example. 1 ... Magnetic detection element, 2 ... Coil part, 3 ... External electrode, 4 ...
Attachment electrode, 5 ... Magnetic layer, 6 ... Conductor pattern, 8 ... Through hole.

Claims (1)

[Claims] 1. A current detector comprising a magnetic detection element (1) and a coil portion (2), wherein the coil portion (2) is a laminate of a magnetic layer (5) and a conductor pattern (6). It has a through hole (8) and is formed of a body. The through hole (8) penetrates the inside of the coil pattern constituted by the conductor pattern (6) in the stacking direction, and the magnetic detection element (1 ) Is attached to a portion of the end surface of the coil portion (2) along the stacking direction that substantially shields the through hole (8). A current detector characterized in that