JP2001305162A - Current detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a current detector which having less malfunctions owing to an external magnetic field. SOLUTION: A current detector 10 includes a magnetic sensor 28 fitted to an insulator substrate 12. On both the sides of the insulator substrate 12, a 1st core 30 and a 2nd core 32 are arranged which face each other across the magnetic sensor 28. The 1st core 30 and 2nd core 32 are made to abut against each other through a through hole bored in the insulator substrate 12. A bobbin 34 is fitted to the 2nd core 32 and wound with a coil 36. A circuit detecting the presence of a current is connected to the coil 36.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current detector, and more particularly to a current detector for detecting, for example, a current flowing through a telephone line while insulating the current.

[0002]

2. Description of the Related Art FIG. 8 is an illustrative view showing one example of a conventional current detector. The current detector 1 is attached to, for example, an insulator substrate 2 on which an electrode pattern is formed. On one surface of the insulator substrate 2, a magnetic sensor 3 such as a Hall element is mounted. On this magnetic sensor 3, L
One end of the letter-shaped core 4 is arranged. The other end of the core 4 is adhered to one surface of the insulator substrate 2. Another U-shaped core 5 is arranged on the other surface of the insulator substrate 2. One end of the core 5 is bonded to a position facing the magnetic sensor 3. The other end of the core 5 is the core 4
Is bonded to the other surface of the insulating substrate 2 at a portion facing the other end of the substrate. Further, a winding 6 is formed on the core 5, and the winding 6 is connected to a circuit for detecting the presence or absence of a current.

In such a current detector 1, when a current flows through a circuit whose current is to be detected, a current flows through a winding 6 connected to the circuit, and a magnetic flux is generated in the cores 4 and 5. When this magnetic flux is applied to the magnetic sensor 3, an electric signal is output from the magnetic sensor 3. Therefore, by measuring the output of the magnetic sensor 3, the current flowing through the circuit can be detected. In such a current detector 1, since the magnetic sensor 3, the cores 4, 5 and the like can be attached from both sides of the insulator substrate 2, the mounting on the insulator substrate 2 is easy, and the mounting can be automated. Can be.

[0004] Such a current detector 1 is used in a device such as a modem or a facsimile which controls the operation according to the state of a telephone line. In such a device, it is necessary to detect the on-hook / off-hook of another telephone, that is, whether or not the line is being used, while isolating it, so that an output signal can be obtained while being insulated from the line. A current detector 1 is used.

[0005]

In such a current detector, when a current flows through the winding, a magnetic field is generated between the ends of the core facing each other across the magnetic sensor, and the magnetic flux applied to the magnetic sensor causes , An output signal is obtained from the magnetic sensor.
Therefore, if there is an external magnetic field in the same direction as the magnetic field generated by the current flowing through the winding, a malfunction may occur.

[0006] Therefore, a main object of the present invention is to provide a current detector which is less likely to malfunction due to an external magnetic field.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a current detector mounted on an insulator substrate, comprising a magnetic sensor formed on one surface of the insulator substrate, and a magnetic sensor disposed on both sides of the insulator substrate. Two cores facing each other across the magnetic sensor;
And a winding formed on one of the cores, wherein a through-hole is formed in the insulator substrate at a portion where the magnetic sensor is not formed, and the two cores are abutted through the through-hole. In such a current detector, an insulating sheet may be interposed between the core and the magnetic sensor facing each other on one side of the insulator substrate. Also, the two cores are
It can be constituted by any combination of a substantially L-shaped, a substantially I-shaped or a substantially U-shaped core.

[0008] By forming a through hole in the insulator substrate and abutting the two cores through the through hole, the abutting portion of the core in the through hole portion can be compared with the end of the core opposing the magnetic sensor. The smaller the reluctance is. Therefore, when an external magnetic field enters, the magnetic flux concentrates on the side with the smaller magnetic resistance, and it is difficult for the external magnetic field to be applied to the magnetic sensor. In addition, by interposing an insulating sheet between the core and the magnetic sensor, the insulation between the core and the magnetic sensor can be improved. In such a current detector, as a combination of two cores, two cores can be selected and combined from a core having a shape such as a substantially L shape, a substantially I shape, and a substantially U shape.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments of the present invention with reference to the accompanying drawings.

[0010]

FIG. 1 is an illustrative view showing one example of a current detector according to the present invention, and FIG. 2 is a plan view thereof. The current detector 10 is an insulator substrate 1 such as an alumina substrate.
2 attached. On one surface of the insulator substrate 12,
As shown in FIG. 3, four electrode patterns 14, 16, 1
8, 20 are formed. These electrode patterns 14, 1
6, 18, and 20 are connected to a magnetic sensor described later. On the other surface of the insulator substrate 12, two electrode patterns 22, 24 are formed as shown in FIG. A winding described later is connected to these electrode patterns 22 and 24. Further, a through hole 26 is formed in the insulator substrate 12 at an intermediate portion between the electrode patterns 22 and 24.

Further, on one surface of the insulator substrate 12,
A magnetic sensor 28 such as a Hall element is attached. The magnetic sensor 28 includes electrode patterns 14, 16, 18, 20
The terminal of the magnetic sensor 28 is connected to the electrode patterns 14, 16, 18, and 20. When a Hall element is used as the magnetic sensor 28, two of the electrode patterns 14, 16, 18, and 20 are used for input to the Hall element, and the other two are used for detection.

A substantially L-shaped first core 30 and a substantially U-shaped second core 32 are arranged with the insulator substrate 12 interposed therebetween. These first core 30 and second core 32
Is formed of a magnetic material. One end of the first core 30 and one end of the second core 32 are arranged to face each other with the magnetic sensor 28 interposed therebetween. Also, the first core 3
The other ends of the zero and second cores 32 are abutted through the through holes 26 of the insulator substrate 12. A gap is formed between one end of the first core 30 and the magnetic sensor 28.

Further, a bobbin 34 is attached to the second core 32, and a winding 36 is applied to the bobbin 34.
The winding 36 is connected to the electrode patterns 22 and 24 formed on the insulator substrate 12. Then, the electrode pattern 22,
Reference numeral 24 is connected to a circuit for detecting whether a current is flowing. As such a circuit, a circuit, such as a telephone line, which needs to detect the use of a line is considered.

When no current flows through the circuit, no current flows through the winding 36 of the current detector 10, so that no magnetic flux is generated. Therefore, no signal is output from the magnetic sensor 28. When a current flows through the circuit, a current flows through the winding 36 to generate a magnetic flux, and the magnetic flux is applied to the porcelain sensor 28 sandwiched between the first core 30 and the second core 32. As a result, a signal is output from the magnetic sensor 28, and it is detected that a current is flowing through the circuit.

In the current detector 10, the insulating substrate 12
Core 30 and second core 32 through through hole 26 of
Are in contact with each other, so that the through holes 2 are smaller than the portions opposed to each other across the insulator substrate 12 and the magnetic sensor 28.
The magnetic resistance of the joint between the cores 30 and 32 on the sixth side is small. Therefore, when an external magnetic field enters, the magnetic flux concentrates on the cores 30 and 32 closer to the through hole 26 than the magnetic sensor 28. Therefore, an external magnetic field is less likely to be applied to the magnetic sensor 28, and malfunctions due to the external magnetic field can be reduced. According to experiments, the current detector 10 of the present invention
The effect of the external magnetic field was reduced to 1/5 to 1/10 of the conventional current detector.

Further, as shown in FIG.
And the required number of insulating sheets 3
8 may be interposed. Core 3 even without insulation sheet
Although the primary side formed by the magnetic sensors 28 is electrically separated from the primary side formed by the magnetic sensors 28, the primary side formed by the magnetic sensors 28 and 32, a more excellent insulating structure is provided by sandwiching the insulating sheet 38. Obtainable. By employing such a structure, for example, an insulating structure conforming to IEC950 can be obtained.

In the current detector 10, the insulating substrate 12
, The first core 30 and the second core 32 can be mounted from both sides, and the current detector 10 can be easily manufactured. As described above, the shape of the core can be changed as long as the core can be mounted from both sides of the insulator substrate 12. For example, as shown in FIG. 6, the first core 30 and the second core 32 may be substantially L-shaped, and the two cores 30 and 32 may abut on the other surface of the insulating substrate 12. In addition, as shown in FIG.
2 is substantially U-shaped with different leg lengths, and a substantially I-shaped first core 30 is formed on one side of the insulator substrate 12.
May be matched. As described above, the shapes of the first core 30 and the second core 32 can be arbitrarily changed as long as the shapes can be mounted on both sides of the insulator substrate 12.

[0018]

According to the present invention, a current detector with less malfunction due to an external magnetic field can be obtained by providing a difference in magnetic resistance between opposing portions of two cores. Also,
By sandwiching an insulating sheet between the first core and the magnetic sensor, an excellent insulating structure can be obtained. Furthermore, in this current detector, the core can be mounted from both sides of the insulator substrate, so that the current detector can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is an illustrative view showing one example of a current detector of the present invention;

FIG. 2 is a plan view of the current detector shown in FIG.

FIG. 3 is a plan view showing one surface side of an insulator substrate to which the current detector shown in FIG. 1 is attached.

FIG. 4 is a plan view showing the other surface side of the insulator substrate to which the current amplifier shown in FIG. 1 is attached.

FIG. 5 is an illustrative view showing another example of the current detector of the present invention;

FIG. 6 is an illustrative view showing still another example of the current detector of the present invention;

FIG. 7 is an illustrative view showing another example of the current detector of the present invention;

FIG. 8 is an illustrative view showing one example of a conventional current detector;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Current detector 12 Insulator substrate 26 Through-hole 28 Magnetic sensor 30 1st core 32 2nd core 34 Bobbin 36 Winding 38 Insulating sheet

Claims (3)

[Claims] 1. A current detector attached to an insulator substrate, comprising: a magnetic sensor formed on one surface of the insulator substrate; and a magnetic sensor disposed on both sides of the insulator substrate and opposed to each other across the magnetic sensor. And a winding formed on one of the cores, wherein a through hole is formed in the insulator substrate at a portion where the magnetic sensor is not formed, and the two cores protrude through the through hole. Keyed, current detector. 2. The current detector according to claim 1, wherein an insulating sheet is sandwiched between the core and the magnetic sensor facing each other on one surface side of the insulator substrate. 3. The current detector according to claim 1, wherein the two cores are configured by a combination of any of a substantially L-shaped, a substantially I-shaped, or a substantially U-shaped core. .