IMPLANTABLE DEVICE WITH BIAS FOR MRI
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Abstract
An ambulatory or implantable device, such as a pacer, defibrillator, or other cardiac rhythm management device, can tolerate magnetic resonance imaging (MRI) or other noise without turning on an integrated circuit diode by selectively providing a bias voltage that can overcome an expected induced voltage resulting from the MRI or other noise.
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Citations
40 Claims
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1-20. -20. (canceled)
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21. An apparatus comprising:
an implantable medical device, comprising; an electrical energy delivery circuit, comprising; an integrated circuit including energy output circuitry, wherein the energy output circuitry includes; a switch having an input terminal, an output terminal, and a gate terminal, wherein the output terminal of the switch is electrically coupled to an output pad of the integrated circuit; and a common mode circuit node referenced to a reference voltage that is set at a specified value that is configured to provide a common mode bias to avoid turn-on of a parasitic well diode associated with the switch during at least; a magnetic resonance imaging (MRI) scanning, of a subject in which the implantable medical device is implanted, in an MRI scanner. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. An apparatus comprising:
an implantable medical device, comprising; an electrical energy delivery circuit, comprising; an integrated circuit including energy output circuitry, wherein the energy output circuitry includes; an electrostimulation supply capacitor, configured to store an electrostimulation voltage to be delivered to a subject; an electrostimulation switch, configured to selectively conduct current from the electrostimulation supply capacitor to be provided to the subject; a coupling capacitor, configured to be located in the electrostimulation current path during an electrostimulation pulse, and configured to be discharged during a recharge pulse; a recharge switch, configured to selectively discharge the coupling capacitor during the recharge pulse, wherein the recharge switch is located on the integrated circuit; a common mode circuit node that is referenced to a first reference voltage during a first mode of operation of the implantable medical device and referenced to a second reference voltage during a second mode of operation, wherein the second reference voltage is set at a specified value to provide a common mode bias that avoids turn-on of parasitic well diodes associated with the electrostimulation switch and the recharge switch during a magnetic resonance imaging (MRI) scanning in an MRI scanner; and a controller circuit, configured to selectively connect the common mode circuit node to the first reference voltage during the first mode of operation, and to the second reference voltage during the second mode of operation, wherein the second mode of operation is configured to provide increased noise-immunity to the implantable medical device by inhibiting turn-on of the parasitic well diodes in the presence of noise interference. - View Dependent Claims (34, 35)
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36. A method comprising:
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providing an implantable medical device comprising a first mode, configured for operation in an environment that does not include magnetic resonance imaging (MRI) scanning-of a subject in which the implantable medical device is implanted, and comprising a second mode configured for operation in an environment that does include at least magnetic resonance imaging (MRI) scanning of a subject in which the implantable medical device is implanted; and referencing a common mode circuit node of energy output circuitry of the implantable medical device to a first reference voltage during the first mode and to a second reference voltage during the second mode to provide a common mode bias during the second mode. - View Dependent Claims (37, 38, 39, 40)
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Specification