Patent ID: 11892325
Assignee: MELEXIS TECHNOLOGIES NV
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 12:
13. A method of determining a linear or angular position of a magnetic sensor device relative to a magnetic source, or vice versa; the magnetic sensor device comprising:
a first, a second, a third and a fourth magnetic sensor element;
a first, second, third and fourth biasing source for biasing said sensor elements;
a first, second, third and fourth amplifier for amplifying a signal originating from said sensor elements;
at least one analog-to-digital converter for digitizing signals originating from said amplifiers;
one or both of a temperature sensor and a differential stress measurements circuit;
a digital processing circuit connected downstream of the analog-to-digital convertor;
the method comprising the steps of:
obtaining one or both of a temperature value and a differential stress value;
a) determining a first magnetic field gradient based on a first mathematical combination of signals obtained from said magnetic sensor elements;
b) determining a second magnetic field gradient based on a second mathematical combination of signals obtained from said magnetic sensor elements;
c) calculating a ratio of the first and the second magnetic field gradient;
d) determining said linear or angular position based on said ratio;

wherein:
step a) comprises: adjusting the biasing source and/or the signal path containing the third and the fourth amplifier using a first predefined function or a first set of control functions of temperature and/or differential stress, to match the signal paths of the magnetic sensor elements when performing the first mathematical combination (or stated in other words: such that a first mathematical combination of the signals obtained from the third and fourth sensor matches the first mathematical combination of the signals obtained from the first and second sensor); and
step b) comprises: adjusting the biasing source and/or the signal path containing the third and the fourth amplifier using a second predefined function or a second set of control functions of temperature and/or differential stress, to match the signal paths of the magnetic sensor elements when performing the second mathematical combination (or stated in other words: such that a second mathematical combination of the signals obtained from the third and fourth sensor matches the second mathematical combination of the signals obtained from the first and second sensor), the second control function or the second set of control functions being different from the first control function or the first set of control functions; and
step d) further comprises: determining said linear or angular position based on said ratio, optionally taking into account a predefined factor K or a predefined function K of temperature.