Current sensor having electromagnetic shield
AssigneeAlps Alpine Co., Ltd.
InventorHiroyuki Hebiguchi
Life of this patent
Estimating the term…
Abstract
First and second magnetic detection units are disposed at positions where an S/N ratio, which is a ratio between the strength of a magnetic field generated by a current to be measured flowing through a current path and the strength of an external magnetic field, is the same. A processing unit determines a normal operation state in a case where the detection signal of the first magnetic detection unit and the detection signal of the second magnetic detection unit approximately match each other. The processing unit determines that either one of the first and second magnetic detection units has failed in a case where the detection signals do not match each other.
Claims9
A current sensor, comprising:
- a current path extending along a first direction and having a first surface extending in the first direction, a current to be measured flowing through the current path;
- an electromagnetic shield surrounding the current path and having a width in the first direction between side ends, the electromagnetic shield having open ends in a direction perpendicular to the first direction so as to form an opening therebetween, the opening exposing the first surface of the current path;
- a substrate disposed in the opening of the electromagnetic shield and extending along the first direction, the substrate having a lower surface facing the first surface of the current path and an upper surface opposite to the lower surface;
- a first magnetic detection unit disposed at a first position on the upper surface of the substrate, the first position being apart from the first surface by a first distance;
- a second magnetic detection unit disposed at a second position on the lower surface of the substrate so as to face the first surface of the current path, the second position being apart from the first surface by a second distance smaller than the first distance, wherein the second position is closer, along the first direction, to one of the side ends of the electromagnetic shield than the first position is.
A current sensor, comprising:
- a current path extending along a first direction and having a first surface extending in the first direction, a current to be measured flowing through the current path;
- an electromagnetic shield surrounding the current path, the electromagnetic shield having open ends in a direction perpendicular to the first direction so as to form an opening therebetween, the opening exposing the first surface of the current path;
- a substrate disposed in the opening of the electromagnetic shield and extending along the first direction, the substrate having a lower surface facing the first surface of the current path and an upper surface opposite to the lower surface;
- a first magnetic detection unit provided on the upper surface of the substrate;
- and
- a second magnetic detection unit provided on the lower surface of the substrate at a position corresponding to that of the first magnetic detection unit such that the first and second magnetic detection unit face each other with the substrate interposed therebetween,
- wherein the positions of the first and second magnetic detection units are shifted from a center of the electromagnetic shield in the first direction.
Dependencies are inferred from the claim text.