US 12,235,332 B2
Position detection device, signal processing circuit, and magnetic sensor system
Shunji Saruki, Tokyo (JP); and Shinichirou Mochizuki, Tokyo (JP)
Assigned to TDK CORPORATION, Tokyo (JP)
Filed by TDK CORPORATION, Tokyo (JP)
Filed on Apr. 25, 2023, as Appl. No. 18/138,859.
Application 18/138,859 is a continuation of application No. 16/742,984, filed on Jan. 15, 2020, granted, now 11,675,025.
Claims priority of application No. 2019-049335 (JP), filed on Mar. 18, 2019.
Prior Publication US 2023/0266408 A1, Aug. 24, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. G01R 33/02 (2006.01); G01B 7/004 (2006.01); G01R 33/00 (2006.01)
CPC G01R 33/0206 (2013.01) [G01B 7/004 (2013.01); G01R 33/0035 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A magnetic sensor system comprising:
a magnetic sensor device; and
a signal processing circuit, wherein
the magnetic sensor device is configured to generate a first detection signal, a second detection signal, and a third detection signal that have correspondences with components in three mutually different directions of a magnetic field at a reference position,
the signal processing circuit includes a first processor and a second processor, the first processor being provided between the magnetic sensor device and the second processor in a circuit configuration of the magnetic sensor system,
the second processor is configured to:
generate sphere information by computation using the first to third detection signals, wherein when coordinates representing a set of values of the first to third detection signals at a certain timing in an orthogonal coordinate system defined by three axes for expressing the values of the first to third detection signals are taken as a measurement point, the sphere information includes data on center coordinates and a radius of a virtual sphere having a spherical surface approximating a distribution of a plurality of measurement points at a plurality of timings; and
correct offsets of the first to third detection signals to generate first to third corrected signals by using the first to third detection signals and the data on the center coordinates included in the sphere information,
the first processor and the second processor are configured such that the sphere information is transmitted from the second processor to the first processor,
the first processor is configured to:
store the sphere information; and
detect a change in offsets of the first to third detection signals by using the first to third detection signals and the sphere information, and output a notification signal indicating the change in the offsets upon detection of the change, and
the first processor includes a storage section that stores the sphere information.