Magnetic inertial sensor and method for operating the same

摘要

An inertial sensor having a body with an excitation coil and a first sensing coil extending along a first axis. A suspended mass includes a magnetic-field concentrator, in a position corresponding to the excitation coil, and configured for displacing by inertia in a plane along the first axis. A supply and sensing circuit is electrically coupled to the excitation coil and to the first sensing coil, and is configured for generating a time-variable flow of electric current that flows in the excitation coil so as to generate a magnetic field that interacts with the magnetic-field concentrator to induce a voltage/current in the sensing coil. The integrated circuit is configured for measuring a value of the voltage/current induced in the first sensing coil so as to detect a quantity associated to the displacement of the suspended mass along the first axis.

主权项

1. An inertial sensor, comprising:
a body of semiconductor material, having a first surface and a second surface, the body including:
an excitation coil;a first sensing coil extending at a first distance from the excitation coil along a first axis; a suspended mass including a magnetic-field concentrator, the suspended mass extending above the first surface and being magnetically coupled to the excitation coil and to the first sensing coil, and configured to be displaced by way of inertia; and a supply and sensing circuit electrically coupled to the excitation coil and to the first sensing coil, and configured to generate a time-variable flow of electric current through the excitation coil to generate a magnetic field that, in use, interacts with said magnetic-field concentrator to induce an electrical quantity in the first sensing coil, the supply and sensing circuit being configured to measure a value of said electrical quantity induced in the first sensing coil to detect a quantity associated with a displacement of the suspended mass, the supply and sensing circuit is further configured to:
acquire an effective frequency of variation in time of the flow of electric current and an effective wavelength associated with said effective frequency;measure an apparent frequency of variation in time of said electrical quantity induced in the first sensing coil and obtaining an apparent wavelength associated to said apparent frequency;compute, on the basis of the values of the effective wavelength and of the apparent wavelength, a value of velocity at which the suspended mass moves; anddetermine a time derivative of the value of velocity to obtain a value of acceleration of the suspended mass.