JPH0622221Y2 - Current detector - Google Patents

Description

[Detailed Description of the Invention] [Field of Use of the Invention] The present invention relates to a current detector used in electronic devices or electric machines and having a Hall element or a magnetoresistive element inserted in a magnetic gap of a ferromagnetic core. ， The hall element or magnetoresistive element and processing circuit section are not affected by external noise.
The present invention relates to a compact and compact current detector.

[Conventional technology]

In the conventional current detector, as shown in FIG. 3, a coil 5 through which a current to be measured flows is wound around a ferromagnetic core 2 of a ring. A magnetic gap is provided in the ferromagnetic core 2, and a magnetic field proportional to the measured current flowing in the coil 5 is generated in the magnetic gap 1. A magnetic sensing element such as a Hall element or a magnetic resistance element is inserted in the magnetic gap 1, and the magnetic sensing element 3 provides an output voltage proportional to the strength of the magnetic field.

In this current detector, when the current to be measured is a current with a fast rise such as a pulse current, an induced voltage proportional to the magnetic field change is generated on the output side of the magnetic sensing element 3 in an electric signal proportional to the desired magnetic field. There is a problem that the current is superimposed as an error.

[Problems to be solved by the invention]

Therefore, a compensating loop method is used to cancel out harmful induced electromotive force in the output pattern of the magnetic sensing element 3 between the magnetic gaps. However, there was a problem that the effect of leakage flux, which is the freezing phenomenon, remains. As a countermeasure, as shown in FIG. 4, the lead wire is twisted from the magneto-sensitive element mounting board section including the magneto-sensitive element compensating the induced electromotive force and the pattern, and the processing circuit board is connected to a remote place. It was

An object of the present invention is to propose a compact current detector which reduces induced electromotive force due to leakage flux without twisting a circuit board mounted with a magnetic sensing element and a processing circuit component at a distance from each other, and has a small error.

[Means for solving problems]

The present invention comprises a ferromagnetic core having a gap formed in a part of a ring-shaped magnetic path and winding, and a magnetic sensitive element arranged in the gap. In a current detector for measuring a voltage induced in an element through a processing circuit component mounted on a circuit component mounting board, a magnetic sensitive element arranged in the gap is a printed circuit board arranged in parallel in the gap. The printed board in the gap and the circuit component mounting board are arranged so as to be substantially orthogonal to each other, and a pattern from the output section of the magnetic sensing element to the processing circuit input section is provided on the circuit component mounting board. A current detector characterized in that it is formed in a loop shape so that the amount of magnetic flux interlinking with the center of the gap as a boundary becomes equal to cancel the induced electromotive voltage due to the leakage magnetic flux of the magnetic gap. A. It is desirable that a lead frame is provided on the circuit component board to connect the output of the magnetic sensing element to the circuit on the circuit component mounting board. In this way, the loop is connected to the lead wire for connecting the circuit component and the lead frame. Will be connected between.

[Action]

Most of the magnetic flux generated in the magnetic gap is accepted by the magnetic sensitive element, and the leakage magnetic flux is orthogonal to the circuit component mounting board.
Further, since a loop for canceling the leakage magnetic flux is provided on the circuit component mounting board, the leakage magnetic flux is prevented from affecting the circuit components and causing an error in the measured value.

〔Example〕

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention, in which a magnetic sensitive element 3 composed of a Hall element or a magnetoresistive element is mounted on a magnetic sensitive element printed board 6 '. The substrate 6'is arranged so that the magnetic sensing element 3 is located in the center of the magnetic gap 1 of the ring-shaped ferromagnetic core 2. A coil 5 for passing a current to be measured is wound on the opposite side of the core 2 from the gap. The magnetic sensitive element printed board 6 ′ is arranged orthogonal to the mounting board 6 of the processing circuit component 13, and the output of the magnetic sensitive element 3 is connected to the processing circuit component 8 via the lead frame 7 on the circuit component mounting board 6. It At this time, since the leakage magnetic flux in the gap does not interlink with the pattern of the circuit component mounting board 6, the induced electromotive voltage does not occur in the circuit on the circuit component mounting board, and only the measured current having no error is detected. Further, the circuit component mounting board can be brought as close as possible to the magnetic gap of the ferromagnetic core 2 to make the entire current detector compact, but when the leakage magnetic field in the magnetic gap becomes strong and its influence cannot be ignored, the magnetic sensitivity is reduced. As shown in FIG. 5, the pattern from the element output section to the processing circuit input section is looped on the circuit component mounting board so that the magnetic fluxes interlinking at the center of the magnetic core gap 1 become equal. By making B12, the induced electromotive voltage due to the leakage magnetic flux can be canceled and a current value without error can be measured. FIG. 2 shows another embodiment when the height of the magnetic core is limited and is lowered.

[Effect of device]

As described above, according to the present invention, the magnetic sensitive element printed board is mounted so as to be orthogonal to the circuit component mounting board, and the loop for canceling the leakage flux is provided on the circuit component mounting board.
Since the leakage magnetic fluxes in the magnetic gap cancel each other out, a current value with a small error can be measured, and the magnetic sensitive element can be arranged close to the circuit component mounting board, so that a compact current detector can be obtained. .

[Brief description of drawings]

1 and 2 are views showing the overall structure of an embodiment according to the present invention, FIGS. 3 and 4 are overall structure diagrams of a conventional current detector, and FIG. 5 is an induced voltage on a circuit mounting board. The circuit which corrects is shown. In the figure, 1: magnetic gap, 2: ferromagnetic core, 3:
Magnetic sensitive element, 4: magnetic field, 5: coil, 6: circuit component mounting board, 6 ': magnetic sensitive element printed board, 7: lead frame,
8: Processing circuit component, 9: Lead wire, 11: Loop A, 1
2: Loop B, 13: Processing circuit component.

Claims (1)

[Scope of utility model registration request] 1. A magnetic core comprising a ferromagnetic core wound with a gap provided in a part of a ring-shaped magnetic path and a magnetic sensitive element arranged in the gap, wherein the measured current flowing through the winding causes In a current detector for measuring a voltage induced in a magnetic sensitive element through a processing circuit component mounted on a circuit component mounting board, a magnetic sensitive element arranged in the gap is printed in parallel in the gap. The printed board in the gap and the circuit component mounting board are mounted on the circuit board so as to be substantially orthogonal to each other, and on the circuit component mounting board, from the output section of the magnetic sensing element to the processing circuit input section. A current detector characterized in that the pattern is formed in a loop shape so that the amount of magnetic flux interlinking with the center of the gap as a boundary becomes equal to cancel the induced electromotive voltage due to the leakage magnetic flux of the magnetic gap. Producer.