Robust inertial sensor self-test
AssigneeInvenSense, Inc.
InventorAurelio Pellegrini
Life of this patent
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Abstract
An inertial sensor such as a MEMS accelerometer or gyroscope has a proof mass that is driven by a self-test signal, with the response of the proof mass to the self-test signal being used to determine whether the sensor is within specification. The self-test signal is provided as a non-periodic self-test pattern that does not correlate with noise such as environmental vibrations that are also experienced by the proof mass during the self-test procedure. The sense output signal corresponding to the proof mass is correlated with the non-periodic self-test signal, such that an output correlation value corresponds only to the proof mass response to the applied self-test signal.
Claims21
A method for performing a self-test of an inertial sensor, comprising:
- generating, by processing circuitry of the inertial sensor, a drive signal;
- generating, by processing circuitry of the inertial sensor, a non-periodic self-test signal pattern;
- providing the drive signal to one or more drive electrodes of the inertial sensor;
- providing the non-periodic self-test signal pattern to one or more self-test drive electrodes of the inertial sensor;
- providing, by the one or more drive electrodes, the drive signal to a proof mass of the inertial sensor, wherein the drive signal functions as a carrier signal for a vibration of the proof mass;
- driving, by the one or more self-test drive electrodes, the proof mass of the inertial sensor in accordance with the non-periodic self-test signal pattern;
- sensing, by one or more sense electrodes of the inertial sensor, the movement of the proof mass while the proof mass is driven by the one or more self-test drive electrodes;
- generating, by the processing circuitry of the inertial sensor, a received signal based on the sensed movement of the proof mass;
- removing the carrier signal from the received signal to generate a sense signal;
- correlating, by the processing circuitry, the sense signal directly with the non-periodic self-test signal pattern;
- and
- identifying, by the processing circuitry, an error based on the correlating.
An inertial sensor with self-test capability, comprising:
- a first signal generator that generates a drive signal;
- a second signal generator that generates a non-periodic self-test signal pattern;
- one or more drive electrodes that receive the drive signal;
- one or more self-test drive electrodes that receive the non-periodic self-test signal pattern;
- a proof mass that is driven by the one or more self-test drive electrodes in accordance with the non-periodic self-test signal pattern and by the one or more drive electrodes in accordance with the drive signal, wherein the drive signal functions as a carrier signal for a vibration of the proof mass;
- one or more sense electrodes that sense movement of the proof mass;
- sense circuitry coupled to the proof mass, wherein the sense circuitry is configured to generate a received signal based on the sensed movement of the proof mass detected by the one or more sense electrodes;
- a frequency mixer configured to remove the carrier signal from the received signal to generate a sense signal;
- and processing circuitry configured to correlate the sense signal directly with the non-periodic self-test signal pattern and identify an error based on the correlation.
A method for performing a self-test of an inertial sensor, comprising:
- generating, by processing circuitry of the inertial sensor, a drive signal;
- generating, by processing circuitry of the inertial sensor, a non-periodic self-test signal pattern;
- providing the drive signal to a proof mass of the inertial sensor, wherein the drive signal functions as a carrier signal for a vibration of the proof mass;
- driving the proof mass in accordance with the non-periodic self-test signal pattern;
- sensing, by one or more sense electrodes of the inertial sensor, the movement of the proof mass while the proof mass is driven by the one or more self-test drive electrodes;
- generating, by the processing circuitry of the inertial sensor, a received signal based on the sensed movement of the proof mass, wherein the sensed movement is based on the driving of the proof mass and an environmental vibration;
- removing the carrier signal from the received signal to generate a sense signal;
- correlating, by the processing circuitry, the sense signal directly with the non-periodic self-test signal pattern, wherein an environmental vibration portion of the signal is not correlated with the non-periodic self-test signal pattern and a driven portion of the sense signal is correlated with the non-periodic self-test signal pattern;
- and
- identifying, by the processing circuitry, an error based on the correlating.
Dependencies are inferred from the claim text.