# US 12,111,158 B2 · MEMS gyroscope control circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,111,158 B2 - Document ID: US12111158B2 - Status: Granted - Kind: B2 - Application number: 18/136,088 - Filed: 2023-04-18 - Published: 2023-08-31 - Granted: 2024-10-08 - Earliest claimed: 2019-06-26 - Assignees: STMicroelectronics S.r.l. - Applicants: STMicroelectronics, Inc. - Inventors: Deyou Fang; Chao-Ming Tsai; Milad Alwardi; Yamu Hu; David McClure - Web page: https://patentgrep.com/patent/US12111158B2 ## CPC - G01C 19/5726: Signal processing - G01C 19/5733: Structural details or topology - G01C 19/5762: the sensing mass being connected to a driving mass, e.g. driving frames - G01C 25/005: {initial alignment, calibration or starting-up of inertial devices} - G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S) ## 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. ## Claims ### Claim 1 A method, comprising: driving a driving mass of a microelectromechanical system (MEMS) gyroscope using a drive loop including a first analog-to-digital converter (ADC) circuit and a first digital signal processing (DSP) circuit; wherein the driving mass is driven in a mechanical oscillation at a resonant drive frequency; generating a system clock independent of and asynchronous to the resonant drive frequency; generating a first clock and a second clock from the system clock; clocking the first ADC circuit of the drive loop with the first clock; and clocking the first DSP circuit of the drive loop with the second clock. ### Claim 2 (depends on 1) The method of claim 1, further comprising: generating a third clock and a fourth clock from the system clock; sensing a Coriolis displacement of a sensing mass coupled to the driving mass with a sensing circuit including a second analog-to-digital converter (ADC) circuit and a second digital signal processing (DSP) circuit; clocking the second ADC circuit of the drive loop with the third clock; and clocking the second DSP circuit of the drive loop with the fourth clock. ### Claim 3 (depends on 2) The method of claim 2, further comprising: generating a quadrature error signal by the sensing circuit from a quadrature component of the sensed Coriolis displacement of the sensing mass; generating a fifth clock from the system clock; generating a compensation force in response to a digital processing of the quadrature error signal; wherein said compensation force is applied to the sensing mass; and wherein digital processing of the quadrature error signal is clocked by the fifth clock. ### Claim 4 A method, comprising: driving a driving mass of a microelectromechanical system (MEMS) gyroscope in a mechanical oscillation at a resonant drive frequency; wherein driving comprises: sensing the mechanical oscillation; and processing a signal dependent on the sensed mechanical oscillation in response to a system clock signal to generate a drive signal for application to cause movement of the driving mass; and generating the system clock signal independent of and asynchronous to the resonant drive frequency. ### Claim 5 (depends on 4) The method of claim 4, wherein processing comprises performing an analog-to-digital conversion clocked by a first clock signal generated from the system clock signal. ### Claim 6 (depends on 5) The method of claim 5, wherein processing comprises performing a digital signal processing operation on an output of the analog-to-digital conversion, wherein said signal processing operation is clocked by a second clock signal generated from the system clock signal. ### Claim 7 (depends on 4) The method of claim 4, wherein processing the signal dependent on the sensed mechanical oscillation comprises: generating an analog sinusoid signal having a frequency corresponding to a frequency of the mechanical oscillation of the driving mass and an amplitude corresponding to an amplitude of the mechanical oscillation of the driving mass; demodulating the analog sinusoid signal using a demodulation clock signal to generate an analog amplitude signal; and performing an analog-to-digital conversion of the analog amplitude signal in response to a first clock signal generated from the system clock signal. ### Claim 8 (depends on 7) The method of claim 7, wherein processing the signal dependent on the sensed mechanical oscillation comprises: generating an oscillation clock signal from the analog sinusoid signal; synchronizing the oscillation clock signal to a second clock signal generated from the system clock signal to output a synchronized oscillation clock signal; determining a phase and frequency of the synchronized oscillation clock signal; and generating a digital sinusoid signal as said drive signal in response to a quadrature shift of the determined phase and frequency. ### Claim 9 A method, comprising: driving a driving mass of a microelectromechanical system (MEMS) gyroscope in a mechanical oscillation at a resonant drive frequency; sensing a Coriolis displacement of the sensing mass; processing a signal dependent on the sensed Coriolis displacement in response to a system clock signal to generate an angular velocity output signal indicative of the Coriolis displacement; and generating the system clock signal independent of and asynchronous to the resonant drive frequency; wherein processing comprises performing an analog-to-digital conversion clocked by a first clock signal generated from the system clock signal. ### Claim 10 (depends on 9) The method of claim 9, wherein processing comprises performing a digital signal processing operation on an output of the analog-to-digital conversion, wherein said signal processing operation is clocked by a second clock signal generated from the system clock signal. ### Claim 11 A method, comprising: driving a driving mass of a microelectromechanical system (MEMS) gyroscope in a mechanical oscillation at a resonant drive frequency; sensing a Coriolis displacement of the sensing mass; processing a signal dependent on the sensed Coriolis displacement in response to a system clock signal to generate an angular velocity output signal indicative of the Coriolis displacement; and generating the system clock signal independent of and asynchronous to the resonant drive frequency; wherein processing comprises: generating an analog Coriolis sinusoid signal having a frequency and phase corresponding to a frequency and phase of the Coriolis displacement of the sensing mass; performing an analog-to-digital conversion of the analog Coriolis sinusoid signal in response to a first clock signal generated from the system clock signal to generate a digital Coriolis sinusoid signal; generating an in phase digital sinusoid signal in response to a frequency and phase of the mechanical oscillation of the driving mass; mixing the in phase digital sinusoid signal with the digital Coriolis sinusoid signal to generate a rate signal indicative of a sensed angular velocity for the angular velocity output signal; and digitally filtering the rate signal in response to a second clock signal generated from the system clock signal. ### Claim 12 A method, comprising: driving a driving mass of a microelectromechanical system (MEMS) gyroscope in a mechanical oscillation at a resonant drive frequency; sensing a Coriolis displacement of the sensing mass; generating a quadrature error signal from a quadrature component of the sensed Coriolis displacement; processing the quadrature error signal in response to a system clock signal to generate a quadrature error compensation force for application to the sensing mass; and generating the system clock signal independent of and asynchronous to the resonant drive frequency. ### Claim 13 (depends on 12) The method of claim 12, wherein processing comprises performing a digital signal processing operation on the quadrature error signal, wherein said signal processing operation is clocked by a digital clock signal generated from the system clock signal. ### Claim 14 (depends on 13) The method of claim 13, wherein performing the digital signal processing operation comprises performing a proportional-integral (PI) control operation.