Circuit arrangement and a method for compensating changes of a transfer factor of a magnetic field sensor arrangement
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Accused Products
Abstract
The invention relates to a circuit configuration for compensating for the changes in a transfer ratio of a magnetic field sensor arrangement. According to one embodiment of the invention, a control loop for effecting this compensation is provided in the form of an integrated circuit whereby the change in transfer ratio is compensated by means of a control signal variation. This circuit configuration includes a series configuration of an A/D converter, a digital controller and a D/A converter exhibiting high precision and high control speed. A control that is significantly more precise and faster than that of the prior art is achieved by virtue of the fact that only a variable portion of regulating variables is fed through the digital controller after which a constant portion of regulating variables for the actual regulating variable used for compensation is added.
24 Citations
39 Claims
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1-20. -20. (canceled)
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21. A circuit arrangement for the compensation of changes of a transfer factor of a magnetic field sensor arrangement wherein the magnetic field sensor arrangement comprises an auxiliary signal generator, a voltage-current transducer and a coil arrangement for producing an first and a second auxiliary magnetic field which are superimposed upon a primary magnetic field to be measured by a first and second magnetic sensor, the magnetic field sensor arrangement further comprising a first summing element for determining a component of an output voltage of the first and second magnetic sensors produced by the auxiliary magnetic fields, the magnetic field sensor arrangement further comprising a correlator that provides a correlator output signal based upon the auxiliary magnetic fields voltage component and the output of the auxiliary signal generator, the circuit arrangement comprising:
an integrated circuit arrangement with a first analog to digital converter with an input operably connected to the output of the correlator and operable to output a digital correlator signal based upon the correlator output signal, a digital regulator with an input operably connected in series with the output of the first analog to digital converter and operable to generate a variable digital regulating signal based upon the digital correlator signal, a digital to analog converter with an input operably connected in series with the output of the digital regulator and operable to output a variable regulating component based upon the output of the digital regulator, and a control element with an input operably connected in series with the output of the digital to analog converter, and operable to output a control signal based upon a summation of the variable regulating component from the digital to analog converter and a constant regulating component. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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32. A method of compensating for transfer changes in magnetic field sensors used to sense a primary magnetic field comprising:
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sensing the primary magnetic field and a first auxiliary magnetic field with a first magnetic field sensor;
providing a first magnetic field sensor output based upon the sensed primary magnetic field and first auxiliary magnetic field;
sensing the primary magnetic field and a second auxiliary magnetic field with a second magnetic field sensor;
providing a second magnetic field sensor output based upon the sensed primary magnetic field and second auxiliary magnetic field;
determining an auxiliary field voltage component based upon the component of the first magnetic field sensor output and the component of the second magnetic field sensor output that result from the sensing of the first auxiliary magnetic field and the sensing of the second auxiliary magnetic field, respectively;
correlating a signal based upon the determined auxiliary field voltage component with a signal from an auxiliary signal generator to provide a correlated output signal;
digitizing the correlated output signal with a first analog to digital converter on an integrated circuit;
generating a variable digital regulating signal based upon the digitized correlated output signal using a digital regulator on the integrated circuit;
generating a variable analog regulating signal based upon the variable digital regulating signal using a digital to analog converter on the integrated circuit; and
generating a control signal operable to affect compensation for the transfer factor of the first magnetic field sensor and the transfer factor of the second magnetic field sensor based upon the variable analog regulating signal and a constant regulating signal. - View Dependent Claims (33, 34, 35, 36, 37, 38, 39)
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Specification