JP2615961B2 - Current detection unit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current detection unit for detecting leakage of magnetic flux generated by a current flowing through a coil by a magnetic sensor.

[Conventional technology]

FIG. 6 shows an example of a conventional current detection unit. This is a coil unit 53 formed by winding a coil 52 of a copper wire around a core 51 of a ring-shaped magnetic material, and a magnetic sensor 55 is arranged in a slit 54 in which a part of the core 51 is cut out. A magnetic field is generated in the core 51 by the flowing current, and the intensity of the magnetic field of the magnetic flux leaking from the slit end face of the core 51 is detected by the magnetic sensor 55 to measure the amount of current flowing in the coil 52.

FIG. 7 shows another conventional example. This forms a substantially annular core 56 by a rod-shaped magnetic body 56a and curved linear magnetic bodies 56b on both sides thereof, and forms a coil unit 58 by winding a coil 57 of a copper wire around the rod-shaped magnetic body 56a. Both ends of the linear magnetic body 56b are opposed to the surface of the magnetic sensor 59, and the amount of current flowing through the coil 57 by detecting the strength of the magnetic field at the end face of the linear magnetic body 56b by the magnetic sensor 59. Is to measure.

[Problems to be solved by the invention]

However, in the conventional current detection unit, the magnetic sensor is arranged in the closed magnetic path of the coil unit,
Since one coil unit and one magnetic sensor are paired, a system that detects multiple currents requires multiple current detection units (multiple coil units and multiple magnetic sensors). Was. For this reason, in the multiple current system, there is a problem that the number of components increases and the area occupied by the current detection unit on the substrate increases.

Also, in a system that detects one current, one coil unit is used for one magnetic sensor,
A relatively large coil unit had to be mounted on the board, and the coil units could not be distributed and arranged in the gap between other components, and it was difficult to design the current detection unit on the board.

Further, in the conventional current detection unit, a coil unit wound around a ring-shaped or substantially annular core forming a closed magnetic circuit is used, so that a space (core hole) in the center of the coil unit is required. The external shape becomes large, which is an obstacle to downsizing the current detection unit. Further, a coil unit in which a coil is wound around a ring-shaped core or the like that forms a closed magnetic circuit has a structure in which coil winding work is difficult to perform, and there is a problem that manufacturing costs are high.

The present invention has been made in view of the above technical background, and its object is to reduce the mounting area on a substrate or the like with a small size, and to easily perform layout design of coil components and the like. An object of the present invention is to provide an inexpensive current sensing unit having a simple structure.

[Means for solving the problem]

For this reason, the current detection unit of the present invention forms a plurality of individual open magnetic path coil components by winding a coil for passing a current to be detected around a core made of a magnetic material and forming an open magnetic path. It is characterized in that the coil components are arranged close to each other so as to be parallel to each other, and a magnetic sensor is arranged between the coil components so that the leakage magnetic flux emitted from each of the coil components passes through the magnetic sensor.

[Action]

In the present invention, to form a coil component by winding a coil around a core forming an open magnetic path, for example, a columnar core,
A plurality of coil components are arranged close to each other so as to be parallel to each other. One magnetic sensor is arranged for each of the plurality of coil components so that the magnetic flux leaking from each coil component passes through the magnetic sensor. If different currents are passed through the coils, the magnetic sensor can be shared. That is, when a different current flows through each coil, the magnetic flux generated in the coil component is detected by the magnetic sensor, and a single magnetic sensor can detect a plurality of currents. For this reason, the number of parts can be reduced, the cost of parts can be reduced, the size of the current detection unit can be reduced, and the mounting area on a substrate or the like can be reduced.

In the case of a system that detects one current, the same current is applied to each coil, and the current is applied in a direction in which the magnetic field generated by each coil component is strengthened at the position of the magnetic sensor. Therefore, if the same sensitivity is obtained, each coil component can be made smaller than in the case of using only one coil unit as in the conventional example, and the plurality of small coil components can be dispersed on a substrate or the like. Since the current detection units can be arranged, the layout design of the current detection units on a substrate or the like is facilitated, which can contribute to high-density mounting of the substrate.

Furthermore, the use of an open magnetic path coil component in which a coil is wound around a core that forms an open magnetic path eliminates the useless space unlike a closed magnetic path coil that is wound around a ring-shaped core, and further detects current. The unit can be downsized. Further, by using the open magnetic path coil component, the winding operation of the coil can be simplified, and the manufacturing cost of the current detection unit can be reduced.

〔Example〕

 Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 show a first embodiment of the present invention, in which two chip coils (open magnetic path coil parts) 4, 4 are arranged vertically on the surface of a substrate 1. FIG. is there.

The chip coil 4 is formed by winding a copper wire coil 2 around an outer periphery of a core 5 formed of a magnetic material such as ferrite. The core 5 forms an open magnetic path, and a flange 7 is provided at both ends of a columnar coil winding portion 6, and the coil 2 is wound around the coil winding portion 6. Since this chip coil 4 has an open magnetic path structure,
When the chip coil 4 is manufactured, the straight coil winding 6
The winding operation of the coil 2 can be easily performed, and the manufacturing cost can be reduced. Further, the size can be reduced as compared with a coil unit having a closed magnetic circuit structure such as a ring shape. Since the chip coil 4 is surface-mounted on the substrate 1 such as a printed wiring board, the flange 7 is provided with two electrodes (not shown), and both ends of the coil 2 are electrically connected to these electrodes. It is connected to the.

The magnetic sensor 3 uses a magneto-electric conversion element such as a Hall element or a magneto-resistive element.

In addition, the substrate 1 is mounted with other electronic circuits and the like together with the current detection unit 10. The substrate 1 is a double-sided printed wiring board. A wiring pattern (not shown) for connecting electrodes of the chip coil 4 is provided on an upper surface of the substrate 1, and a lead terminal of the magnetic sensor 3 is provided on a lower surface. 9, a wiring pattern (not shown) is provided.

Then, as shown in FIG. 1, the lead terminals 9 are inserted into the holes 11 of the substrate 1 to set the magnetic sensor 3 on the upper surface of the substrate 1, and the tips of the lead terminals 9 are soldered to the lower surface wiring pattern of the substrate 1. Soldered to. On both sides of the magnetic sensor 3, a pair of chip coils with the axial direction perpendicular to the substrate 1 is provided.
4 and 4 are arranged vertically, and each electrode is soldered to the upper surface wiring pattern of the substrate 1 with solder 13. Lead terminal 9
The electrodes of the chip coil 4 and the electrodes of the chip coil 4 may be soldered on the same side of the substrate 1. However, if they are soldered on the opposite sides, a short circuit or the like due to a solder bridge can be avoided. Thus, the magnetic sensing portion 8 of the magnetic sensor 3 is sandwiched between the flanges 7 above the two vertically arranged chip coils 4,4.

When detecting two current systems using the current detection unit 10 assembled as described above, two coils 2,
The electrodes are connected to 2 so that currents of different circuits flow. Then, when a current flows through any of the coils 2,
A magnetic flux as shown in FIG. 1 is generated in the core 5, and a magnetic flux leaking from the upper flange 7 is detected by the magnetic sensor 3, and the magnetic sensor 3 detects the strength of the magnetic field, thereby detecting the coil 2 Measure the amount of current flowing through. In this case, the magnetic sensor 3 can detect any current flowing through any of the coils 2, so that one magnetic sensor 3 can detect two currents, and the magnetic sensor 3 is connected to the two coils 2. It can be shared by. If the magnitudes of the currents flowing through the two coils are different from each other and are substantially constant, it is possible to determine which coil has the current flowing or whether the current has flowed through both the coils.

Next, when detecting one current, two coils
The coils 2, 2 are connected in series or in parallel, for example, by the wiring pattern of the substrate 1, so that a current flows through both coils 2, 2 at the same time to generate a magnetic flux, and as shown in FIG. The connection is made such that the magnetic flux density passing through the magnetic sensing part 8 of the sensor 3 increases. Therefore, in order to obtain the same sensitivity, each coil 2, 2 can be made smaller than the case of only one coil, and this small two coils 2, 2
2 can be dispersedly arranged on the substrate 1, and can be arranged in a gap between other components, and the layout design of the coils 2, 2 is facilitated.
Moreover, by using the two open magnetic path coils 2 and 2, the magnetic flux partially constitutes a closed circuit as shown by the broken line in FIG. 2, and the leakage of the magnetic flux to the outside of the unit can be reduced. The sensitivity is improved.

In the embodiment of FIGS. 1 and 2, the magnetic sensing portion of the magnetic sensor is arranged between the upper flanges, but may be arranged between the lower flanges.

FIG. 3 shows a second embodiment of the present invention (the same parts as those in the embodiment of FIG. 1 are denoted by the same reference numerals and description thereof will be omitted. The same applies to the following embodiments). Chip coil
4 and 4 are arranged coaxially on the upper surface of the substrate 1, and both chip coils
The magnetic sensing part 8 of the magnetic sensor 3 is located between the end faces 4 and 4. Each of the chip coils 4 is arranged such that the leakage magnetic flux exiting from the end face passes through the magnetic sensing portion 8.

FIG. 4 shows a third embodiment of the present invention, in which a pair of laid-down chip coils 4, 4 are arranged in parallel on the upper surface of the substrate 1, and a gap between the flanges 7, 7 of both chip coils 4, 4 is provided. The magnetic sensing part 8 of the magnetic sensor 3 is located at the position shown in FIG. Also in this embodiment, the leakage magnetic flux from the flanges 7, 7 of the two chip coils 4, 4 passes through the magnetic sensing part 8.

FIG. 5 shows a fourth embodiment of the present invention, in which chip coils 4, 4 are arranged on both sides of a magnetic sensor 3 and one ends of magnetic yokes 14, 14 are mounted on flanges 7, 7. Attach,
The other ends of the yokes 14 are brought close to the surface of the magnetic sensing portion 8 so that the magnetic flux emitted from the chip coil 4 is concentrated on the magnetic sensing portion 8. That is, the magnetic flux of the coils 2, 2 is concentrated on the magnetic sensing unit 8, so that the sensitivity of the current detection unit 10 is improved.

The embodiment of the present invention is not limited to the above embodiment, and various other embodiments are possible. For example, in each of the above embodiments, two chip coils are used, but three or more chip coils may be used.

〔The invention's effect〕

According to the present invention, when used in a system for detecting a plurality of currents, a magnetic sensor can be shared for each coil component, component costs can be reduced by reducing the number of components, and the current detection unit can be further reduced. The size can be reduced, and the mounting area on a substrate or the like can be reduced. Also, if it is used for a system that detects one current, relatively small coil components can be dispersedly arranged on a substrate or the like, and the degree of freedom of arrangement on the substrate or the like can be increased to facilitate the layout design. High-density mounting of the substrate is also facilitated. Furthermore, since an open magnetic path coil component in which a coil is wound around a core forming an open magnetic path is used, useless space such as a closed magnetic path coil unit in which a coil is wound around a ring-shaped core that forms a closed magnetic path is used. Does not occur, and the current detection unit can be further downsized. Further, by using the open magnetic path coil component, the winding operation of the coil can be simplified, and the manufacturing cost of the current detection unit can be reduced.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing a first embodiment of the present invention, FIG. 2 is an explanatory view showing the flow of magnetic flux of the same, and FIG. 3 is a front view showing a second embodiment of the present invention. 4 is a plan view showing a third embodiment of the present invention, FIG. 5 is a front view showing a fourth embodiment of the present invention, FIG. 6 is a perspective view of a conventional example, and FIG. It is a perspective view of another conventional example. 2 ... coil 3 ... magnetic sensor 4 ... chip coil (open magnetic circuit coil part) 5 ... core

Claims (1)

(57) [Claims] 1. A plurality of individual open magnetic path coil components are formed by winding a coil for passing a current to be detected around a core made of a magnetic material and forming an open magnetic path, and these coil components are parallel to each other. A current detection unit, wherein a magnetic sensor is arranged between the coil components so that leakage magnetic flux from each of the coil components passes through the magnetic sensor.