Patent ID: 11927645
Assignee: INFINEON TECHNOLOGIES AG
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A capacitive sensor, comprising:
a first electrode structure;
a second electrode structure that is counter to the first electrode structure, wherein the second electrode structure is movable relative to the first electrode structure in response to an external force acting thereon, wherein the second electrode structure is capacitively coupled to the first electrode structure to form a first capacitor having a first capacitance that changes with a change in a distance between the first electrode structure and second electrode structure, wherein the first capacitance is representative of the external force,
wherein a pull-in event occurs when the first electrode structure is in direct contact with the second electrode structure causing the first capacitance to be equal to or greater than a pull-in capacitance and a non-pull-in event occurs when the first electrode structure is not in direct contact with the second electrode structure causing the first capacitance to be less than the pull-in capacitance;
a signal generator configured to apply a first electrical signal at an input or at an output of the first capacitor to induce a first voltage transient response at the output of first capacitor, wherein the first electrical signal is a pull-in signal configured to induce a pull-in event in the absence of a fault or a non-pull-in signal configured induce a non-pull-in event in the absence of a fault; and
a diagnostic circuit configured to detect a fault in the capacitive sensor by measuring a first time constant of the first voltage transient response and detecting the fault based on the first time constant and based on whether the first electrical signal is the pull-in signal or the non-pull-in signal.