MRI compatible implantable medical devices and methods

A method for operating an implantable medical device (IMD), the method comprising:

• providing, for the IMD, a housing comprising an electrically conductive material;
• providing, for the IMD, pulse generation circuitry disposed within the housing for generating electrical voltage pulses;
• providing, for the IMD, a protection diode located in series with and between the housing and the pulse generation circuitry;
• providing, for the IMD, a resistor located in series with the protection diode between the housing the pulse generation circuitry;
• providing, for the IMD, a first switch located in series with the protection diode and the resistor, the switch configured to selectively isolate the housing from the pulse generation circuitry;
• and
• limiting, for the IMD, a magnetic-resonance-imaging-induced current through the protection diode using the resistor.

An implantable medical device comprising:

• a housing comprising an electrically conductive material;
• pulse generation circuitry disposed within the housing for generating electrical voltage pulses;
• a protection diode located in series with and between the housing and the pulse generation circuitry;
• a resistor located in series with the protection diode between the housing the pulse generation circuitry, the resistor located between the diode and the pulse generation circuitry;
• and
• a first switch located in series with the protection diode and the resistor, the switch configured to selectively isolate the housing from the pulse generation circuitry;
• wherein the pulse generation circuitry is otherwise electrically isolated from the housing.