Granted Patent B2

US 12,385,739 · App. 18/057,711 · Granted Aug 12, 2025

Inventor: Marco Milani (Bellinzago Novarese, IT)

Assignee: STMICROELECTRONICS S.r.l.

G01C19/5712

Abstract

Claims (74)

1. A microelectromechanical gyroscope device, comprising:

a detection structure that includes a mobile mass; and

an integrated electronic circuit, coupled to the detection structure and the integrated electronic circuit configured to:

provide a bias signal to the detection structure to cause oscillation at a resonance frequency;

acquire a detection signal from the detection structure indicative of a detected angular velocity;

receive a power-down signal;

receive a start-up signal;

implement a start-up phase in response to the start-up signal that is received after a previous power-down phase, during the start-up phase the integrated electronic circuit is configured to:

bias the mobile mass to increase the oscillation up to a target oscillation amplitude; and

implement a maintenance phase in response to the target oscillation amplitude, the integrated electronic circuit includes:

a time counter configured to measure a duration of a time interval from the previous power-down phase,

the integrated electronic circuit is configured to:

compare the measured duration of the time interval and a wait interval associated with a decay time of the oscillation; and

bias the mobile mass during the start-up phase in response to the comparison.

2. The device according to claim 1 wherein a value of the wait interval is a function of a quality factor of the mobile mass of the detection structure.

3. The device according to claim 1 wherein the integrated electronic circuit includes a non-volatile memory, configured to store a value of the wait interval.

4. The device according to claim 1 wherein the integrated electronic circuit is configured to: activate the time counter and start a pre-power down phase upon receipt of a power-down signal configured to cause turn-off of the gyroscope device; and bias the mobile mass during the start-up phase as a function of the measured duration of the time interval, which elapses between the reception of the power-down signal and the reception of the start-up signal, in the event that the measured duration is shorter than the wait interval.

5. The device according to claim 4 wherein the integrated electronic circuit is configured to cause turn-off of the gyroscope device and of the time counter if the measured duration reaches the wait interval.

6. The device according to claim 1 wherein the start-up phase is divided into a plurality of sub-phases; and wherein the integrated electronic circuit is configured to bias the mobile mass during the start-up phase by eliminating one or more of the sub-phases.

7. The device according to claim 1 wherein the start-up phase is divided into a plurality of sub-phases; and wherein the integrated electronic circuit is configured to bias the mobile mass during the start-up phase by reducing a predetermined duration for one or more of the sub-phases.

8. The device according to claim 1 wherein the integrated electronic circuit comprises a control stage and a biasing stage, controlled by the control stage to implement the biasing of the detection structure.

9. The device according to claim 1 wherein the time counter comprises an oscillator.

10. A method, comprising:

operating a microelectromechanical gyroscope device having a detection structure with a mobile mass, the operating being by an integrated electronic circuit, coupled to the detection structure;

oscillating the detection structure at a resonance frequency with a bias signal from a biasing stage of the integrated electronic circuit;

receiving a start-up signal;

implementing a start-up phase in response to the start-up signal which is after a previous power-down phase;

biasing the mobile mass to increase in the oscillation to a target oscillation amplitude;

implementing a maintenance phase in response to reaching the target oscillation amplitude;

detecting a duration of a time interval from the previous power-down phase;

carrying out a comparison between the detected duration of the time interval and a wait interval associated with a decay time of the mobile mass oscillation; and

biasing the mobile mass during the start-up phase based on the comparison.

11. The method according to claim 10 , comprising determining a value of the wait interval, as a function of a quality factor of the mobile mass of the detection structure.

12. The method according to claim 10 , comprising: activating a count of the duration of the time interval and starting a pre-power down phase when a power-down signal is received designed to cause turn-off of the gyroscope device; and adjusting biasing of the mobile mass during the start-up phase as a function of the detected duration of the time interval, which elapses between the reception of the power-down signal and the reception of a start-up signal designed to cause powering of the gyroscope device, in the event that the detected duration is shorter than the wait interval.

13. The method according to claim 12 , comprising causing the turn-off of the gyroscope device and of a time counter stage if the detected duration reaches the wait interval.

14. The method according to claim 10 wherein the start-up phase is divided into a plurality of sub-phases; comprising adjusting the biasing of the mobile mass during the start-up phase by eliminating one or more of the sub-phases and/or reducing a predetermined duration for one or more of the sub-phases.

15. The method according to claim 14 wherein the sub-phases comprise:

a first sub-phase, starting-up the mobile mass oscillation;

a second sub-phase, maintaining the mobile mass oscillation; and

a third sub-phase, applying full energy for a predefined time;

and wherein adjusting the biasing of the mobile mass during the start-up phase comprises:

if the duration of the time interval is shorter than half of a decay time of the mobile mass oscillation, eliminating the first and the third sub-phases and implementing only the second sub-phase;

if the duration of the time interval is comprised between ½ and ¾ of the decay time, eliminating the first sub-phase and shortening the third sub-phase; and

if the duration of the time interval is comprised between ¾ of the decay time and the decay time, eliminating the first sub-phase only.

16. A method, comprising:

receiving a first power-down signal with an integrated circuit that is coupled to a detection structure of a micro-electromechanical system;

initiating a first pre-power down phase by starting a counter;

determining whether a time count value of the first pre-power down phase is greater than or less than a wait time interval;

receiving a start-up signal before the time count value exceeds the wait time interval;

biasing the detection structure as a function of the time count value.

17. The method of claim 16 , comprising receiving a second power down signal with the integrated circuit and initiating a second pre-power down phase by starting the counter.

18. The method of claim 17 , comprising determining whether a time count value of the second pre-power down phase is greater than or less than the wait time interval.

19. A microelectromechanical gyroscope device, comprising:

a detection structure that includes a mobile mass; and

an integrated electronic circuit, coupled to the detection structure and the integrated electronic circuit configured to:

provide a bias signal to the detection structure to cause oscillation at a resonance frequency;

acquire a detection signal from the detection structure indicative of a detected angular velocity;

receive a power-down signal;

receive a start-up signal;

implement a start-up phase in response to the start-up signal that is received after a previous power-down phase, during the start-up phase the integrated electronic circuit is configured to:

bias the mobile mass to increase the oscillation up to a target oscillation amplitude; and

implement a maintenance phase in response to the target oscillation amplitude,

wherein the integrated electronic circuit includes a time counter configured to measure a duration of a time interval from the previous power-down phase, and is configured to bias the mobile mass during the start-up phase as a function of the measured duration of the time interval,

wherein the start-up phase is divided into a plurality of sub-phases, and the integrated electronic circuit is configured to bias the mobile mass during the start-up phase by eliminating one or more of the sub-phases or reducing a predetermined duration for one or more of the sub-phases.

20. A method, comprising:

operating a microelectromechanical gyroscope device having a detection structure with a mobile mass, the operating being by an integrated electronic circuit, coupled to the detection structure;

oscillating the detection structure at a resonance frequency with a bias signal from a biasing stage of the integrated electronic circuit;

receiving a start-up signal;

implementing a start-up phase in response to the start-up signal which is after a previous power-down phase, the start-up phase being divided into sub-phases;

biasing the mobile mass to increase in the oscillation to a target oscillation amplitude;

implementing a maintenance phase in response to reaching the target oscillation amplitude;

detecting a duration of a time interval from the previous power-down phase; and

biasing the mobile mass during the start-up phase as a function of the measured duration of the time interval; and

adjusting the biasing of the mobile mass during the start-up phase by eliminating one or more of the sub-phases or reducing a predetermined duration for one or more of the sub-phases.

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (20)