Coil actuated sensor with sensitivity detection

A magnetic field sensor comprising:

• a coil responsive to an AC coil drive signal;
• a first magnetic field sensing element responsive to a first sensing element drive signal and configured to simultaneously detect a directly coupled magnetic field generated by the coil and a reflected magnetic field generated by an eddy current induced in a conductive target by the coil, the conductive target disposed proximate to the first magnetic field sensing element, the first magnetic field sensing element further configured to generate a first magnetic field signal;
• a coil driver configured to generate the AC coil drive signal;
• a first sensing element driver configured to generate the first sensing element drive signal;
• a first oscillator connected to the coil driver and to the first sensing element driver and configured to oscillate at a frequency f;
• a first output signal generator configured to generate a first output signal of the magnetic field sensor in response to the first magnetic field signal and indicative of the reflected magnetic field, wherein the first output signal generator comprises:
• a first temperature sensor configured to measure temperature;
• a first material type selector comprising parameters to compensate for temperature effects and for a type of material used for the conductive target;
• a first temperature compensator configured to generate an output signal in response to the temperature measured by the first temperature sensor and to one or more of the parameters from the first material type selector;
• and
• a first linearization module configured to perform a linear regression on the output signal generated by the first temperature compensator and configured to provide the first output signal;
• a second magnetic field sensing element responsive to a second sensing element drive signal and configured to simultaneously detect the directly coupled magnetic field generated by the coil and the reflected magnetic field generated by the eddy current induced in the conductive target by the coil,
• a second sensing element driver configured to generate a second sensing element drive signal;
• and
• a second oscillator connected to the second sensing element driver and configured to oscillate at a frequency f+90°,
• wherein the first magnetic field sensing element is driven by the first sensing element drive signal having the frequency f and the second magnetic field sensing element is driven by the second sensing element drive signal having the frequency f+90°.