# US 11,906,306 B2 · Inertial measurement circuit, corresponding device and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,906,306 B2 - Document ID: US11906306B2 - Status: Granted - Kind: B2 - Application number: 17/750,074 - Filed: 2022-05-20 - Published: 2022-12-08 - Granted: 2024-02-20 - Earliest claimed: 2021-06-04 - Assignees: STMicroelectronics S.r.l. - Applicants: STMicroelectronics S.r.l. - Inventors: Giacomo Langfelder; Leonardo Gaffuri Pagani; Luca Guerinoni; Luca Giuseppe Falorni; Patrick Fedeli; Paola Carulli - Web page: https://patentgrep.com/patent/US11906306B2 ## CPC - G01C 19/5712: the devices involving a micromechanical structure - G01C 19/5776: Signal processing not specific to any of the devices covered by groups G01C19/5607 - G01C19/5719 - 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 In an embodiment a circuit includes an inertial measurement unit configured to be oscillated via a driving signal provided by driving circuitry, a lock-in amplifier configured to receive a sensing signal from the inertial measurement unit and a reference demodulation signal which is a function of the driving signal and provide an inertial measurement signal based on the sensing signal, wherein the reference demodulation signal is affected by a variable phase error, phase meter circuitry configured to receive the driving signal and the sensing signal and provide, as a function of a phase difference between the driving signal and the sensing signal, a phase correction signal for the reference demodulation signal and a correction node configured to apply the phase correction signal to the reference demodulation signal so that, in response to the phase correction signal being applied to the reference demodulation signal, the phase error is maintained in a vicinity of a reference value. ## Claims ### Claim 1 A circuit comprising: an inertial measurement unit configured to be oscillated via a driving signal provided by driving circuitry; a lock-in amplifier configured to: receive a sensing signal from the inertial measurement unit and a reference demodulation signal which is a function of the driving signal; and provide an inertial measurement signal based on the sensing signal, wherein the reference demodulation signal is affected by a variable phase error; phase meter circuitry configured to: receive the driving signal and the sensing signal; and provide, as a function of a phase difference between the driving signal and the sensing signal, a phase correction signal for the reference demodulation signal; and a correction node configured to apply the phase correction signal to the reference demodulation signal so that, in response to the phase correction signal being applied to the reference demodulation signal, the phase error is maintained in a vicinity of a reference value. ### Claim 2 (depends on 1) The circuit of claim 1, further comprising a trimming node arranged between the phase meter circuitry and the correction node, wherein the trimming node is configured to trim the phase correction signal by a reference phase correction value. ### Claim 3 (depends on 1) The circuit of claim 1, further comprising sensing circuitry arranged between the inertial measurement unit and the lock-in amplifier, wherein the sensing circuitry is configured to provide the sensing signal. ### Claim 4 (depends on 3) The circuit of claim 3, wherein the sensing circuitry is configured to provide the sensing signal to both, the lock-in amplifier and the phase meter circuitry. ### Claim 5 (depends on 1) The circuit of claim 1, wherein the phase meter circuitry is coupled to input signal paths for the driving signal and the sensing signal, respectively, the input signal paths comprising: bandpass filter circuitry; and/or saturation circuitry. ### Claim 6 (depends on 5) The circuit of claim 5, wherein the saturation circuitry comprises a cascaded arrangement of an instrumentation amplifier and a high-gain stage. ### Claim 7 (depends on 1) The circuit of claim 1, wherein the phase meter circuitry comprises a digital phase meter. ### Claim 8 (depends on 1) The circuit of claim 1, wherein the inertial measurement unit comprises a MEMS gyroscope. ### Claim 9 A device, comprising: a circuit, comprising: an inertial measurement unit configured to be oscillated via a driving signal provided by driving circuitry; a lock-in amplifier configured to: receive a sensing signal from the inertial measurement unit and a reference demodulation signal which is a function of the driving signal, and provide an inertial measurement signal based on the sensing signal, wherein the reference demodulation signal is affected by a variable phase error; phase meter circuitry configured to: receive the driving signal and the sensing signal, and provide, as a function of a phase difference between the driving signal and the sensing signal, a phase correction signal for the reference demodulation signal; and a correction node configured to apply the phase correction signal to the reference demodulation signal so that, in response to the phase correction signal being applied to the reference demodulation signal, the phase error is maintained in a vicinity of a reference value; and user circuitry coupled to the lock-in amplifier in the circuit, wherein the user circuitry is configured to exploit the inertial measurement signal produced by the lock-in amplifier. ### Claim 10 A method comprising: oscillating an inertial measurement unit via a driving signal provided by driving circuitry; receiving, by a lock-in amplifier, a sensing signal from the inertial measurement unit and a reference demodulation signal which is a function of the driving signal; providing, by the lock-in amplifier, an inertial measurement signal based on the sensing signal and the reference demodulation signal, wherein the reference demodulation signal is affected by a variable phase error, receiving, by a phase meter circuitry, the driving signal and the sensing signal, and providing, as a function of a phase difference between the driving signal and the sensing signal, a phase correction signal for the reference demodulation signal; and applying, by a correction node, the phase correction signal to the reference demodulation signal of the lock-in amplifier so that, in response to the phase correction signal being applied to the reference demodulation signal of the lock-in amplifier, the phase error is maintained in a vicinity of a reference value. ### Claim 11 (depends on 10) The method of claim 10, further comprising trimming, by a trimming node, the phase correction signal by a reference phase correction value. ### Claim 12 (depends on 10) The method of claim 10, further comprising providing, by a sensing circuitry arranged between the inertial measurement unit and the lock-in amplifier, the sensing signal. ### Claim 13 (depends on 12) The method of claim 12, wherein the sensing circuitry provides the sensing signal to both, the lock-in amplifier and the phase meter circuitry. ### Claim 14 (depends on 9) The device of claim 9, wherein the circuit further comprises a trimming node arranged between the phase meter circuitry and the correction node, wherein the trimming node is configured to trim the phase correction signal by a reference phase correction value. ### Claim 15 (depends on 9) The device of claim 9, wherein the circuit further comprises sensing circuitry arranged between the inertial measurement unit and the lock-in amplifier, wherein the sensing circuitry is configured to provide the sensing signal. ### Claim 16 (depends on 15) The device of claim 15, wherein the sensing circuitry is configured to provide the sensing signal to both, the lock-in amplifier and the phase meter circuitry. ### Claim 17 (depends on 9) The device of claim 9, wherein the phase meter circuitry is coupled to input signal paths for the driving signal and the sensing signal, respectively, the input signal paths comprising: bandpass filter circuitry; and/or saturation circuitry. ### Claim 18 (depends on 17) The device of claim 17, wherein the saturation circuitry comprises a cascaded arrangement of an instrumentation amplifier and a high-gain stage. ### Claim 19 (depends on 9) The device of claim 9, wherein the phase meter circuitry comprises a digital phase meter. ### Claim 20 (depends on 9) The device of claim 9, wherein the inertial measurement unit comprises a MEMS gyroscope.