Open-circuit sensors utilizing inductive coupling

Abstract

Systems, circuits, and methods provide for detection of open-circuit states in an external conductor using inductive coupling. An on-chip coil is used to generate a reference magnetic field. An in-package conductor loop is connected to the external conductor. When the external conductor is continuous, the reference magnetic field generates an induced current in the in-package conductor whereas no induced current is generated when the external conductor is broken. The presence of an induced current produces an induced magnetic field, tending to cancel the reference magnetic field. The cancellation or attenuation of the reference magnetic field can be detected by an included magnetic field sensor and a comparator. Examples can include use of a closed loop acting as a feedback loop. The feedback loop can adjust the strength of a feedback magnetic field directed at the magnetic field sensor and used to compensate for nonlinearities of the magnetic field sensor.