Patent ID: 9238580
Filing Date: 2016-01-19
CPC Classification: B81B,B81C,G01N

Claim Text:
1. A MEMS sensor having a runtime self-test circuit, the MEMS sensor comprising: a micro-electromechanical device that outputs, during runtime operation, a device output signal; a detection circuit configured to detect, during the runtime operation of the micro-electromechanical device, a stimulus produced by the micro-electromechanical system in a sensor bandwidth of the device output signal, the stimulus having a magnitude above a predetermined detection threshold of the detection circuit, the detection circuit further configured to produce a sensor output signal based on the detected stimulus; and a self-test circuit configured to: inject, during the runtime operation of the micro-electromechanical device, a self-test signal into a signal path of the micro-electromechanical device including a MEMS structure involved with generation of the stimulus in the sensor bandwidth of the device output signal, wherein the self-test signal is a spread-spectrum signal having a test-signal bandwidth that overlaps at least a portion of the sensor bandwidth; detect a test signal component in the test-signal bandwidth of the device output signal based on a reference test signal corresponding to the injected self-test signal, the test signal component have a magnitude below the detection threshold of the detection circuit; and produce a test output signal indicating a status for the micro-electromechanical system based on the test signal component and the reference test signal.