公开(公告)号：US12204001B2

公开(公告)日：2025-01-21

申请号：US18013453

申请日：2021-07-07

Applicant: TDK CORPORATION

Inventor： Atsushi Matsuda ,  Yosuke Nagakubo

IPC: G01R33/022 ,  G01R33/028

Abstract: A gradient magnetic field sensor includes: an AC power supply connection terminal to which a first power supply terminal included in an AC power supply is connected; a first magnetic core connected between the connection terminal and the ground; a second magnetic core connected in parallel with the first magnetic core between the connection terminal and ground; an AC current control unit connected between the connection terminal and at least one of the first magnetic core and the second magnetic core and configured to control an AC current flowing through at least one of the first and second magnetic core; a first detection coil wound around the first magnetic core; a second detection coil wound around second magnetic core and differentially-connected with the first detection coil; and a detection circuit that detects a voltage difference between first voltage output from first detection coil and second voltage output from the second.

公开(公告)号：US11022659B2

公开(公告)日：2021-06-01

申请号：US15776234

申请日：2016-10-20

Applicant: TDK CORPORATION

Inventor： Yuki Asazuma ,  Kei Tanabe ,  Akihiro Unno ,  Atsushi Matsuda ,  Masashi Takahashi

IPC: G01R33/09 ,  H01L43/08 ,  G01R33/00 ,  G01R33/025

Abstract: An object of the present invention is to provide a magnetic sensor that can reduce influences of a disturbance magnetic field while ensuring high detection sensitivity. The magnetic sensor includes a sensor chip 20 having an element formation surface 20S on which magnetic detection elements MR3, MR4 are formed, a first magnetic member 31 placed on the element formation surface 20S and having a first height H1 as a height from the element formation surface 20S, and a second magnetic member 32 located on an opposite side of the magnetic detection elements MR3, MR4 to the first magnetic member 31 and having a second height H2 lower than the first height H1. According to the present invention, because the height H2 of the second magnetic member 32 is lower than that of the first magnetic member 31, a detection magnetic field attracted to the second magnetic member 32 can be reduced while a disturbance magnetic field is shielded by the second magnetic member 32. Accordingly, influences of the disturbance magnetic field can be reduced while high detection sensitivity is ensured.