JPH08248066A - Current detector - Google Patents

Abstract

PURPOSE: To obtain a small-sized highly accurate current detector in which the labor required for assembling is reduced by forming the current detection coil into a ring. CONSTITUTION: A current detection coil 3 is formed into a ring and mounted on a circuit board 1 along with electronic devices 6 and then a magnetic core 2 is inserted into the coil 3 thus constituting a magnetic circuit part. In such current detector, when a current flow through the coil, flux is generated around the coil with density proportional to the magnitude of current and a magnetic closed loop is formed in the core 2. Flux of the magnetic closed loop generated in the core 2 is then converted into a DC voltage proportional to the flux density using a magnetoelectric conversion element 4. The DC voltage signal is subjected to a series of signal processing, including offset voltage regulation and amplification, by means of an amplifier circuit 5 and an electronic device 6 before being delivered on a connection lead 7 to the outside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting the magnitude of a current flowing through a current line, and more particularly to a current detecting device which can be realized with a small size, low cost and high accuracy.

[0002]

2. Description of the Related Art In recent years, there has been a demand for highly accurate detection of a current flowing through a motor in order to improve the accuracy of motor control and to save electric power, and due to an increase in demand for incoming call detection on a telephone line due to the expansion of the information communication field, Low cost, high precision, small size
A lightweight current detection circuit has been demanded as an important electronic component.

A conventional current detecting device will be described below with reference to FIG. FIG. 2 is a perspective view of a conventional current detection device.

In FIG. 2, reference numeral 11 is a circuit board. 1
Reference numeral 2 denotes a magnetic core provided so as to sandwich the circuit board 11, which forms a closed magnetic field of the current flowing through the current detection coil 13 and gives the magnetoelectric conversion element 14 a magnetic flux density proportional to the current flowing through the current detection coil 13. . Magnetoelectric conversion element 14
Generates a voltage proportional to the current flowing in the current detection coil 13 and performs processing such as offset voltage adjustment and amplification to a predetermined value by a circuit composed of the amplification circuit 15 and the electronic component 16 to connect the signals. Output to the outside through the lead 17.

When the current detecting coil 13 is attached to the magnetic core 12, a conductor is first prepared, and the conductor is passed through a closed circuit of the magnetic core 12 to round the conductor.
By repeating the same operation several times thereafter, the predetermined current detection coil 13 is formed.

[0006]

However, in the above-mentioned conventional configuration, the current detecting coil 13 is such that after the magnetic core 12 is mounted on the circuit board 11, the conductive wire is passed through the closed loop of the magnetic core 12 to round the conductive wire. A predetermined current detection coil 13 must be formed by repeating the same operation several times thereafter, and when the current detection coil 13 is fixed to the circuit board 11, an insulating resin or the like is used to perform a subsequent process. Therefore, there is a problem in that it is necessary to stop the resin with a resin, which requires a long time for assembling the device, resulting in a large number of man-hours. Further, in the method for forming the current detection coil 13 as described above, since the current detection coil 13 cannot be wound uniformly, there is a problem in that the characteristics of the device vary by that much, and high accuracy and miniaturization cannot be achieved. Was.

The present invention solves the above-mentioned conventional problems by reducing the number of steps for assembling the current detecting device, and reducing the size and size of the device.
An object is to provide a highly accurate current detection device.

[0008]

In order to solve the above-mentioned conventional problems, the present invention creates a ring-shaped current detecting coil, mounts it on a circuit board together with electronic parts, and then mounts a magnetic core on the current detecting coil. The magnetic circuit part is configured by being inserted into.

[0009]

According to this structure, when a current is passed through the current detecting coil, a magnetic flux density proportional to the magnitude of the current is obtained in the magnetic core, and this magnetic flux density is supplied to the magnetoelectric conversion element and proportional to the magnetic flux density. The voltage is obtained.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A current detecting device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1A is a perspective view of a current detecting device according to an embodiment of the present invention, and FIG. 1B is a sectional view thereof. In FIG. 1, reference numeral 1 is a circuit board. Reference numeral 2 is a magnetic core fitted and provided on the circuit board 1. Reference numeral 3 denotes a current detection coil wound around the magnetic core 2, which forms a closed magnetic field of the current flowing through the current detection coil 3 and is used as a magnetoelectric conversion element 4
, A magnetic field proportional to the current flowing through the current detection coil 3 is applied to. Reference numeral 4 denotes a magnetoelectric conversion element provided on the circuit board 1 in the vicinity of the magnetic core 2, which generates a voltage proportional to the current flowing in the current detection coil 3 and is electrically connected to the circuit composed of the amplifier circuit 5 and the electronic component 6. Are connected to the connection lead 7 to perform processing such as offset voltage adjustment and amplification to a predetermined value, and connect the signal to the connection lead 7.
To the outside. The connection lead 7 projects from the same surface as the current detection coil 3. Magnetoelectric conversion element 4
Is so provided that the upper surface has the maximum sensitivity when it is arranged perpendicularly to the end surface of the magnetic core 2. Reference numeral 8 denotes a soldering land for fixing the current detection coil 3 and the circuit board 1.

The operation of the current detecting device configured as described above will be described below.

First, when a current flows through the current detection coil 3, a magnetic flux density proportional to the magnitude of the current is generated around the current detection coil 3 as Ampere's right-handed screw law, and is generated in the magnetic core 2. The magnetic flux thus formed forms a magnetic closed loop inside the magnetic core 2. Next, the magnetic closed loop magnetic flux generated in the magnetic core 2 is converted into a current voltage proportional to the magnetic flux density using the magnetoelectric conversion element 4. Next, the signal converted into the DC voltage by the magnetoelectric conversion element 4 is subjected to a series of signal processing such as offset voltage adjustment and amplification by the amplifier circuit 5 and the electronic component 6 according to the application of the external device to be used. There is. The processed signal is output to the outside using the connection lead 7. The connection lead 7 is connected to the amplifier circuit 5
It also serves to supply power to the electronic component 6.

[0014]

As described above, according to the current detecting device of the present invention, the magnetic core is inserted into the ring-shaped current detecting coil to facilitate the assembling of the device and to reduce the size of the device.
It is possible to provide a current detection device that enables cost reduction and high accuracy.

[Brief description of drawings]

FIG. 1A is a perspective view of a current detection device according to an embodiment of the present invention, and FIG.

FIG. 2 is a perspective view of a conventional current detection device.

[Explanation of symbols]

 1 Circuit Board 2 Magnetic Core 3 Current Detection Coil 4 Magnetoelectric Converter 5 Amplifier Circuit 6 Electronic Component 7 Connection Lead 8 Soldering Land

Claims (4)

[Claims] 1. A circuit board, a magnetic core fitted into the circuit board, a current detection coil wound around the magnetic core, and a magnetic-electric conversion provided in a closed magnetic circuit formed by the magnetic core. A current detecting device comprising an element, wherein the current detecting coil and the connecting lead are projected from the same surface. 2. The current detection device according to claim 1, wherein the current detection coil is previously formed in a ring shape. 3. The current detecting device according to claim 1, wherein a current detecting coil is inserted into one end of the magnetic core in a closed loop shape. 4. The current detection device according to claim 1, wherein a plurality of current detection coils are provided laterally in a ring shape.