Patent ID: 8457760

Claim:
An active implantable medical device (AIMD), comprising: a conductive device housing for the AIMD, the housing containing tissue-stimulating or biological-sensing circuits connected to a first electrical point, the first electrical point being electrically connectable to an electrode configured for tissue-stimulating or biological-sensing; b) at least one frequency variable impedance diversion circuit electrically connecting between the first electrical point and a second electrical point; c) an energy dissipating surface provided by the device housing as a third electrical point; and d) at least one diode residing between the second electrical point and the third electrical point, wherein the diode is actuatable in response to a bias applied across the second and third electrical points to thereby electrically connect the diversion circuit from the first electrical point to the third electrical point at the energy dissipating surface, e) wherein with the diode electrically connecting the second electrical point to the third electrical point and: i) at relatively high frequencies attendant to the AIMD being subjected to an MRI RF pulse field, the diversion circuit acts as a relatively low impedance circuit from the first electrical point to the third electrical point at the energy dissipating surface, and ii) at relatively low frequencies attendant to the AIMD being subjected to an MRI gradient field, the diversion circuit acts as a relatively high impedance circuit from the first electrical point to the third electrical point at the energy dissipating surface.