公开(公告)号：US11817281B2

公开(公告)日：2023-11-14

申请号：US17680119

申请日：2022-02-24

Applicant: Texas Instruments Incorporated

Inventor： Anand Gopalan ,  Nicholas Oborny ,  Milos Acanski

IPC: H01H47/32 ,  H01H47/00 ,  H01H85/30

CPC classification number: H01H47/002 ,  H01H47/32 ,  H01H85/30 ,  H01H2047/003

Abstract: A method of detecting welded contacts in a relay. The method includes performing, at a first point in time, the applying of a drive to the activation coil to conduct a coil current through the activation coil, the coil current increasing to a first current level, the first current level being less than a pull-in current of the relay; responsive to the coil current reaching the first current level, turning off the drive to the activation coil to discharge the coil current at a first clamping voltage; and measuring a first discharge time corresponding to a first inductance from the turning off of the drive to the activation coil to the coil current reaching a second current level, the second current level being less than the first current level. These operations are repeated at a second point in time to obtain a second inductance. Comparison of the first inductance and second inductance determines whether a difference between the first and second inductances exceeds a comparison criterion.

公开(公告)号：US20230268153A1

公开(公告)日：2023-08-24

申请号：US17680119

申请日：2022-02-24

Applicant: Texas Instruments Incorporated

Inventor： Anand Gopalan ,  Nicholas Oborny ,  Milos Acanski

IPC: H01H47/00 ,  H01H85/30 ,  H01H47/32

CPC classification number: H01H47/002 ,  H01H47/32 ,  H01H85/30 ,  H01H2047/003

Abstract: A method of detecting welded contacts in a relay. The method includes performing, at a first point in time, the applying of a drive to the activation coil to conduct a coil current through the activation coil, the coil current increasing to a first current level, the first current level being less than a pull-in current of the relay; responsive to the coil current reaching the first current level, turning off the drive to the activation coil to discharge the coil current at a first clamping voltage; and measuring a first discharge time corresponding to a first inductance from the turning off of the drive to the activation coil to the coil current reaching a second current level, the second current level being less than the first current level. These operations are repeated at a second point in time to obtain a second inductance. Comparison of the first inductance and second inductance determines whether a difference between the first and second inductances exceeds a comparison criterion.