MEMS gyroscope start-up process and circuit

A method for start-up of a microelectromechanical system (MEMS) gyroscope, comprising:

• not applying a drive signal to the MEMS gyroscope;
• sensing phase, frequency and amplitude of a residual mechanical oscillation of the MEMS gyroscope while the drive signal is not applied;
• determining if the sensed frequency of the residual mechanical oscillation is a spurious mode frequency that is offset from a resonance frequency of a desired resonant mode;
• determining if a quality factor of the residual mechanical oscillation from the sensed amplitude of the residual mechanical oscillation exceeds a quality factor threshold;
• and
• when the sensed frequency is determined to be the spurious mode frequency and the determined quality factor is determined to exceed the quality factor threshold, then:
• applying an anti-phase signal as the drive signal to the MEMS gyroscope, said anti-phase signal having a frequency corresponding to the sensed frequency and a phase that is 180° out of phase with the sensed phase of the residual mechanical oscillation.