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US 9,804,222 B2Granted
Magnetic field sensor with shared path amplifier and analog-to-digital-converter
AssigneeAllegro MicroSystems, LLC
InventorsCraig S. Petrie, Bryan Cadugan
Life of this patent
Estimating the term…
Abstract
Methods and apparatus for processing a signal comprise at least one circuit configured to generate a measured signal during a measured time period and a reference signal during a reference time period. Also included is at least one dual- or multi-path analog-to-digital converter comprising at least a first processing circuit configured to process the measured signal, at least a second processing circuit configured to process the reference signal, and a third processing circuit configured to process both the measured signal and the reference signal.
Claims18
A magnetic field sensor comprising:
- at least one magnetic field sensing element configured to generate a measured magnetic field signal responsive to an external magnetic field and to generate a reference magnetic field signal responsive to a reference magnetic field;
- a signal path comprising an amplifier and an analog-to-digital converter for processing the measured magnetic field signal during a first time period to generate a sensor output signal indicative of the external magnetic field, and for processing the reference magnetic field signal during a second time period, the analog-to-digital converter comprising at least one integrator circuit having a first capacitor configured to process the measured magnetic field signal and a second capacitor configured to process the reference magnetic field signal, wherein the analog-to-digital converter is responsive to the measured magnetic field signal to generate a digital measured magnetic field signal and responsive to the reference magnetic field signal to generate a digital reference magnetic field signal;
- a controller configured to switch the first capacitor with the second capacitor to enable the first capacitor to process the reference magnetic field signal;
- and
- a comparator circuit to compare the reference magnetic field signal to a threshold value during the second time period to determine whether a fault is present;
- wherein the first time period and the second time period are non-overlapping time periods.
3 more elements
A magnetic field sensor comprising:
- at least one magnetic field sensing element configured to generate a measured magnetic field signal responsive to an external magnetic field and to generate a reference magnetic field signal responsive to a reference magnetic field;
- a signal path comprising:
- a shared portion for processing the measured magnetic field signal during a first time period to generate a sensor output signal indicative of the external magnetic field, and for processing the reference magnetic field signal during a second time period, wherein the first and second time periods are non-overlapping time periods;
- a dedicated portion for processing the measured magnetic field signal during the first time period;
- and
- at least one integrator circuit having a first capacitor configured to process the measured magnetic field signal and a second capacitor configured to process the reference magnetic field signal;
- and
- a comparator circuit to compare the reference magnetic field signal to a threshold value during the second time period to determine whether a fault is present;
- and
- a controller configured to switch the first capacitor with the second capacitor to enable the dedicated portion of the signal path to process the reference magnetic field signal.
7 more elements
A magnetic field sensor comprising:
- at least one magnetic field sensing element configured to generate a measured magnetic field signal responsive to an external magnetic field and to generate a reference magnetic field signal responsive to a reference magnetic field;
- a signal path for processing the measured magnetic field signal during a first time period to generate a sensor output signal indicative of the external magnetic field and for processing the reference magnetic field signal during a second time period, the signal path comprising at least one integrator circuit having a first capacitor configured to process the measured magnetic field signal and a second capacitor configured to process the reference magnetic field signal, wherein the first time period and the second time period are non-overlapping time periods;
- a controller configured to switch the first capacitor with the second capacitor to enable the second capacitor of the integrator circuit to process the reference magnetic field signal;
- a comparator circuit to compare the reference magnetic field signal to a threshold value during the second time period to determine whether a fault is present;
- and
- a diagnostic trim circuit configured to adjust a gain of the reference magnetic field signal, an offset of the reference magnetic field signal, or both.
3 more elements
A magnetic field sensor comprising:
- means for generating a measured magnetic field signal responsive to an external magnetic field;
- means for generating a reference magnetic field signal responsive to a reference magnetic field;
- a signal path comprising:
- means for processing the measured magnetic field signal during a first time period to generate a sensor output signal indicative of the external magnetic field;
- means for processing the reference magnetic field signal during a second time period;
- and
- means for converting the measured magnetic field signal and the reference magnetic field signal to digital signals, the means for converting comprising at least one integrator circuit having a first capacitor configured to process the measured magnetic field signal and a second capacitor configured to process the reference magnetic field signal;
- and
- means for selectively coupling the first capacitor to the signal path during the first time period and coupling the second capacitor to the signal path during the second time period;
- and
- means for detecting a fault and generating a signal indicative of whether a fault is present;
- wherein the first time period and the second time period are non-overlapping time periods.
9 more elements
Dependencies are inferred from the claim text.