US 12,455,178 B2
Inductive linear stroke sensor using dual tracks with different periodicity
Emanuele Andrea Casu, Annecy (FR); Ross Eisenbeis, Litchfield, NH (US); and Solène Bastien, Naves-Parmelan (FR)
Assigned to Allegro MicroSystems, LLC, Manchester, NH (US)
Filed by Allegro MicroSystems, LLC, Manchester, NH (US)
Filed on Dec. 22, 2023, as Appl. No. 18/394,642.
Prior Publication US 2025/0207949 A1, Jun. 26, 2025
Int. Cl. G01D 5/20 (2006.01)
CPC G01D 5/2053 (2013.01) 30 Claims
OG exemplary drawing
 
1. A system comprising:
a target having a first track and a second track, the first track including one or more first features, and the second track including one or more second features, the target having a respective target length;
a first receiving coil that is aligned with the first track, the first receiving coil having a first period length, the first receiving coil being configured to sense a first reflected magnetic field that is generated by any of the first features, the first receiving coil being configured to generate a first magnetic field signal in response to the first reflected magnetic field;
a second receiving coil that is aligned with the first track, the second receiving coil having a second period length, the second receiving coil being configured to sense the first reflected magnetic field, the second receiving coil being configured to generate a second magnetic field signal in response to the first reflected magnetic field, the second magnetic field signal being off-phase from the first magnetic field signal;
a third receiving coil that is aligned with the second track, the third receiving coil having a third period length, the third receiving coil being configured to sense a second reflected magnetic field that is generated by any of the second features, the third receiving coil being configured to generate a third magnetic field signal in response to the second reflected magnetic field; and
a fourth receiving coil that is aligned with the second track, the fourth receiving coil having a fourth period length, the fourth receiving coil being configured to sense the second reflected magnetic field, the fourth receiving coil being configured to generate a fourth magnetic field signal in response to the second reflected magnetic field, the fourth magnetic field signal being off-phase from the third magnetic field signal,
wherein the respective target length is less than any of the first period length, the second period length, the third period length, and the fourth period length,
wherein, the target is spaced apart from the first receiving coil, the second receiving coil, the third receiving coil, and the fourth receiving coil, and
wherein the target is configured to travel along each of the first receiving coil, the second receiving coil, the third receiving coil, and the fourth receiving coil.