Hall sensor circuit for magnetic field detection in implantable medical device
AssigneeMedtronic, Inc.
InventorsJalpa S. Shah, Robert W. Hocken, Jr., Joel Sivula, Wesley A. Santa
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Abstract
Techniques are described for magnetic field detection using a plurality of Hall sensors and chopper-amplifier circuit. Determination that a magnetic field is present from measurement from one of the Hall sensors may trigger confirmation or confirmation and reconfirmation of the presence of the magnetic field from measurements from one or more of the other Hall sensors.
Claims21
A method of magnetic field detection, the method comprising:
- modulating, at a frequency, a current applied through first and second terminals of a Hall sensor;
- amplifying a voltage across third and fourth terminals of the Hall sensor to generate an amplified voltage, wherein the voltage is generated at least in part in response to the current being applied through the first and second terminals of the Hall sensor;
- demodulating, at the same frequency, the amplified voltage to generate a demodulated signal;
- determining presence of a magnetic field based on the demodulated signal, wherein the presence of the magnetic field is determined without application of a current through the third and fourth terminals of the Hall sensor and without amplification of a voltage across the first and second terminals;
- and
- entering an implantable medical device into a safe mode based in part on the determination of the presence of the magnetic field.
An implantable medical device (IMD) for magnetic field detection, the IMD comprising:
- a Hall sensor;
- a magnetic field detection circuit configured to:
- modulate, at a frequency, a current applied through first and second terminals of the Hall sensor;
- amplify a voltage across third and fourth terminals of the Hall sensor to generate an amplified voltage, wherein the voltage is generated at least in part in response to the current being applied through the first and second terminals of the Hall sensor;
- and
- demodulate, at the same frequency, the amplified voltage to generate a demodulated signal;
- and
- processing circuitry configured to:
- determine presence of a magnetic field based on the demodulated signal, wherein the presence of the magnetic field is determined without application of a current through the third and fourth terminals of the Hall sensor and without amplification of a voltage across the first and second terminals;
- and
- enter the IMD into a safe mode based in part on the determination of the presence of the magnetic field.
An implantable medical device (IMD) for magnetic field detection, the IMD comprising:
- means for modulating, at a frequency, a current applied through first and second terminals of a Hall sensor;
- means for amplifying a voltage across third and fourth terminals of the Hall sensor to generate an amplified voltage, wherein the voltage is generated at least in part in response to the current being applied through the first and second terminals of the Hall sensor;
- means for demodulating, at the same frequency, the amplified voltage to generate a demodulated signal;
- means for determining presence of a magnetic field based on the demodulated signal, wherein the presence of the magnetic field is determined without application of a current through the third and fourth terminals of the Hall sensor and without amplification of a voltage across the first and second terminals;
- and
- means for entering an implantable medical device into a safe mode based in part on the determination of the presence of the magnetic field.
Dependencies are inferred from the claim text.