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US 11,686,754 B2Granted
Combination magnetic and capacitive sensor
AssigneeLexmark International, Inc.
InventorsJames Howard Ellis, Jr., Keith Bryan Hardin
Life of this patent
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Abstract
Described is an invention that adds capacitive sensing ability with a single magnetic field sensor location or distributed within an array of surfaces of the sensor. The capacitive sensing can be achieved by modifying a classic Hall effect sensor or putting separate capacitive sensor plates in close proximity to the hall effect sensor.
Claims10
A capacitive sensor device comprising:
- two Hall sensor plates;
- a differential amplifier used as a single ended amplifier with an analog to digital converter;
- a voltage source providing a reference threshold voltage;
- additional switching transistors that can change a state between a high and low impedance;
- and
- conducting electrodes adjacent to the Hall plates, wherein if the electrodes are connected with a conducting closed loop, then a resulting shorted turn will tend to reject alternating current magnetic fields but will not affect a static magnetic field if applied long enough and the shorted turn has sufficient loss.
3 more elements
A magnetic and capacitive sensor device comprising:
- time interval where Hall plate electrodes are connected to make a Hall effect magnetic sensor;
- a time interval where the Hall plate electrodes are connected to make a capacitive sensor;
- and
- a switch control that enables the change of switched connections.
1 more element
Dependencies are inferred from the claim text.