Self test for capacitive pressure sensors

Abstract

During a first cycle of operation, first and second bottom electrodes of a split bottom electrode are electrically connected together. A total capacitance between the split bottom electrode and a top electrode layer is measured to determine the ambient pressure. Accordingly, pressure, e.g., tire pressure, is measured during the first cycle of operation. In a second cycle of operation, the first and second bottom electrodes are electrically disconnected. A first capacitance between the first bottom electrode and top electrode layer and a second capacitance between second bottom electrode and top electrode layer are measured. The difference between the first capacitance and the second capacitance is calculated and compared to a fault indicating capacitance variation to determine if the pressure sensor device is operating normally or malfunctioning. Accordingly, a self-test of the pressure sensor device is performed during the second cycle of operation.

Dependencies are inferred from the claim text.