Abstract: At start-up of a microelectromechanical system (MEMS) gyroscope, the drive signal is inhibited, and the phase, frequency and amplitude of any residual mechanical oscillation is sensed and processed to determine a process path for start-up. In the event that the sensed frequency of the residual mechanical oscillation is a spurious mode frequency and a quality factor of the residual mechanical oscillation is sufficient, an anti-phase signal is applied as the MEMS gyroscope drive signal in order to implement an active dampening of the residual mechanical oscillation. A kicking phase can then be performed to initiate oscillation. Also, in the event that the sensed frequency of the residual mechanical oscillation is a resonant mode frequency with sufficient drive energy, a quadrature phase signal with phase lock loop frequency control and amplitude controlled by the drive energy is applied as the MEMS gyroscope drive signal in order to induce controlled oscillation.

Abstract: A microelectromechanical system (MEMS) gyroscope includes a driving mass and a driving circuit that operates to drive the driving mass in a mechanical oscillation at a resonant drive frequency. An oscillator generates a system clock that is independent of and asynchronous to the resonant drive frequency. A clock generator circuit outputs a first clock and a second clock that are derived from the system clock. The drive loop of the driving circuit including an analog-to-digital converter (ADC) circuit that is clocked by the first clock and a digital signal processing (DSP) circuit that is clocked by the second clock.

Abstract: A microelectromechanical system (MEMS) gyroscope sensor has a sensing mass and a quadrature error compensation control loop for applying a force to the sensing mass to cancel quadrature error. To detect fault, the quadrature error compensation control loop is opened and an additional force is applied to produce a physical displacement of the sensing mass. A quadrature error resulting from the physical displacement of the sensing mass in response to the applied additional force is sensed. The sensed quadrature error is compared to an expected value corresponding to the applied additional force and a fault alert is generated if the comparison is not satisfied.

Abstract: A microelectromechanical system (MEMS) gyroscope includes a driving mass and a driving circuit that operates to drive the driving mass in a mechanical oscillation at a resonant drive frequency. An oscillator generates a system clock that is independent of and asynchronous to the resonant drive frequency. A clock generator circuit outputs a first clock and a second clock that are derived from the system clock. The drive loop of the driving circuit including an analog-to-digital converter (ADC) circuit that is clocked by the first clock and a digital signal processing (DSP) circuit that is clocked by the second clock.

Abstract: A microelectromechanical system (MEMS) accelerometer sensor has a mobile mass and a sensing capacitor. To self-test the sensor, a test signal having a variably controlled excitation voltage and a fixed pulse width is applied to the sensing capacitor. The leading and trailing edges of the test signal are aligned to coincide with reset phases of a sensing circuit coupled to the sensing capacitor. The variably controlled excitation voltage of the test signal is configured to cause an electrostatic force which produces a desired physical displacement of the mobile mass. During a read phase of the sensing circuit, a variation in capacitance of sensing capacitor due to the actual physical displacement of the mobile mass is sensed for comparison to the desired physical displacement.

Abstract: A microelectromechanical system (MEMS) accelerometer sensor has a mobile mass and a sensing capacitor. To self-test the sensor, a test signal is applied to the sensing capacitor during a reset phase of a sensing circuit coupled to the sensing capacitor. The test signal is configured to cause an electrostatic force which produces a physical displacement of the mobile mass corresponding to a desired acceleration value. Then, during a read phase of the sensing circuit, a variation in capacitance of sensing capacitor due to the physical displacement of the mobile mass is sensed. This sensed variation in capacitance is converted to a sensed acceleration value. A comparison of the sensed acceleration value to the desired acceleration value provides an indication of an error in operation of the MEMS accelerometer sensor if the sensed acceleration value and desired acceleration value are not substantially equal.

Abstract: A microelectromechanical system (MEMS) gyroscope sensor has a sensing mass and a quadrature error compensation control loop for applying a force to the sensing mass to cancel quadrature error. To detect fault, the quadrature error compensation control loop is opened and an additional force is applied to produce a physical displacement of the sensing mass. A quadrature error resulting from the physical displacement of the sensing mass in response to the applied additional force is sensed. The sensed quadrature error is compared to an expected value corresponding to the applied additional force and a fault alert is generated if the comparison is not satisfied.

Abstract: A microelectromechanical system (MEMS) gyroscope sensor has a sensing mass and a quadrature error compensation control loop for applying a force to the sensing mass to cancel quadrature error. To detect fault, the quadrature error compensation control loop is opened and an additional force is applied to produce a physical displacement of the sensing mass. A quadrature error resulting from the physical displacement of the sensing mass in response to the applied additional force is sensed. The sensed quadrature error is compared to an expected value corresponding to the applied additional force and a fault alert is generated if the comparison is not satisfied.

Abstract: A microelectromechanical system (MEMS) gyroscope includes a driving mass and a driving circuit that operates to drive the driving mass in a mechanical oscillation at a resonant drive frequency. An oscillator generates a system clock that is independent of and asynchronous to the resonant drive frequency. A clock generator circuit outputs a first clock and a second clock that are derived from the system clock. The drive loop of the driving circuit including an analog-to-digital converter (ADC) circuit that is clocked by the first clock and a digital signal processing (DSP) circuit that is clocked by the second clock.

Abstract: In one embodiment, a method for detecting functional state of a microelectromechanical (MEMS) sensor is described. The method includes monitoring an input common-mode feedback (ICMFB) voltage generated by an ICMFB circuit coupled to the MEMS sensor through a plurality of nodes. The method also includes determining, using the monitored ICMFB voltage, whether all of the plurality of nodes of the MEMS sensor are electrically connected to the ICMFB circuit.

Abstract: A microelectromechanical system (MEMS) gyroscope includes a driving mass and a driving circuit that operates to drive the driving mass in a mechanical oscillation at a resonant drive frequency. An oscillator generates a system clock that is independent of and asynchronous to the resonant drive frequency. A clock generator circuit outputs a first clock and a second clock that are derived from the system clock. The drive loop of the driving circuit including an analog-to-digital converter (ADC) circuit that is clocked by the first clock and a digital signal processing (DSP) circuit that is clocked by the second clock.

Abstract: A drive signal is applied to a MEMS gyroscope having several intrinsic resonant modes. Frequency and amplitude of mechanical oscillation in response to the drive signal is sensed. At startup, the drive signal frequency is set to a kicking frequency offset from a resonant frequency corresponding to a desired one of the intrinsic resonant modes. In response to sufficient sensed amplitude of mechanical oscillation at the kicking frequency, a frequency tracking process is engaged to control the frequency for the drive signal to sustain mechanical oscillation at the frequency of the desired one of the plurality of intrinsic resonant modes as the oscillation amplitude increases. When the increasing amplitude of the mechanical oscillation exceeds a threshold, a gain control process is used to exercise gain control over the applied drive signal so as to cause the amplitude of mechanical oscillation to match a further threshold. At that point start-up terminates.

Abstract: In one embodiment, a method for detecting functional state of a microelectromechanical (MEMS) sensor is described. The method includes monitoring an input common-mode feedback (ICMFB) voltage generated by an ICMFB circuit coupled to the MEMS sensor through a plurality of nodes. The method also includes determining, using the monitored ICMFB voltage, whether all of the plurality of nodes of the MEMS sensor are electrically connected to the ICMFB circuit.

Abstract: A microelectromechanical system (MEMS) gyroscope sensor has a sensing mass and a quadrature error compensation control loop for applying a force to the sensing mass to cancel quadrature error. To detect fault, the quadrature error compensation control loop is opened and an additional force is applied to produce a physical displacement of the sensing mass. A quadrature error resulting from the physical displacement of the sensing mass in response to the applied additional force is sensed. The sensed quadrature error is compared to an expected value corresponding to the applied additional force and a fault alert is generated if the comparison is not satisfied.

Abstract: A microelectromechanical system (MEMS) gyroscope includes a driving mass and a driving circuit that operates to drive the driving mass in a mechanical oscillation at a resonant drive frequency. An oscillator generates a system clock that is independent of and asynchronous to the resonant drive frequency. A clock generator circuit outputs a first clock and a second clock that are derived from the system clock. The drive loop of the driving circuit including an analog-to-digital converter (ADC) circuit that is clocked by the first clock and a digital signal processing (DSP) circuit that is clocked by the second clock.

Abstract: A microelectromechanical system (MEMS) accelerometer sensor has a mobile mass and a sensing capacitor. To self-test the sensor, a test signal is applied to the sensing capacitor during a reset phase of a sensing circuit coupled to the sensing capacitor. The test signal is configured to cause an electrostatic force which produces a physical displacement of the mobile mass corresponding to a desired acceleration value. Then, during a read phase of the sensing circuit, a variation in capacitance of sensing capacitor due to the physical displacement of the mobile mass is sensed. This sensed variation in capacitance is converted to a sensed acceleration value. A comparison of the sensed acceleration value to the desired acceleration value provides an indication of an error in operation of the MEMS accelerometer sensor if the sensed acceleration value and desired acceleration value are not substantially equal.

Abstract: A drive signal is applied to a MEMS gyroscope having several intrinsic resonant modes. Frequency and amplitude of mechanical oscillation in response to the drive signal is sensed. At startup, the drive signal frequency is set to a kicking frequency offset from a resonant frequency corresponding to a desired one of the intrinsic resonant modes. In response to sufficient sensed amplitude of mechanical oscillation at the kicking frequency, a frequency tracking process is engaged to control the frequency for the drive signal to sustain mechanical oscillation at the frequency of the desired one of the plurality of intrinsic resonant modes as the oscillation amplitude increases. When the increasing amplitude of the mechanical oscillation exceeds a threshold, a gain control process is used to exercise gain control over the applied drive signal so as to cause the amplitude of mechanical oscillation to match a further threshold. At that point start-up terminates.

Abstract: In one embodiment, a method for detecting functional state of a microelectromechanical (MEMS) sensor is described. The method includes monitoring an input common-mode feedback (ICMFB) voltage generated by an ICMFB circuit coupled to the MEMS sensor through a plurality of nodes. The method also includes determining, using the monitored ICMFB voltage, whether all of the plurality of nodes of the MEMS sensor are electrically connected to the ICMFB circuit.

Abstract: A modulated digital input signal is passed through a conditioning circuit to generate a first input signal. An error amplifier circuit receives the first input signal and a second input signal, and controls the operation of a MOS transistor to generate an output signal that is current modulated. The output signal is sensed to generate a feedback signal. A switching circuit selectively applies the feedback signal as the second input signal in response to a transition of the modulated digital input signal from a first logic state to a second logic state. The switching circuit alternatively selectively applies a fixed reference signal as the second input signal to the error amplifier in response to a transition of the modulated digital input signal from the second logic state to the first logic state.

Abstract: A modulated digital input signal is passed through a conditioning circuit to generate a first input signal. An error amplifier circuit receives the first input signal and a second input signal, and controls the operation of a MOS transistor to generate an output signal that is current modulated. The output signal is sensed to generate a feedback signal. A switching circuit selectively applies the feedback signal as the second input signal in response to a transition of the modulated digital input signal from a first logic state to a second logic state. The switching circuit alternatively selectively applies a fixed reference signal as the second input signal to the error amplifier in response to a transition of the modulated digital input signal from the second logic state to the first logic state.