Recharge of implanted medical devices

A method for recharging a power source located in an implantable medical device configured for implantation within a patient, the method comprising:

• energizing, by recharging circuitry, a first electrical coil to generate a first magnetic field having a first magnetic field direction;
• energizing, by the recharging circuitry, a second electrical coil to generate a second magnetic field having a second magnetic field direction opposing the first magnetic field direction relative to a longitudinal axis extending between the first electrical coil and the second electrical coil,
• wherein an interaction between the first magnetic field and the second magnetic field generates a resultant magnetic field within a recharging envelope located in an area between the first electrical coil and the second electrical coil when the first electrical coil and the second electrical coil are electrically energized;
• inducing, by the resultant magnetic field, an electrical current in a third coil within the implantable medical device by imposing the resultant magnetic field onto the third coil when the third coil is located within the recharging envelope and the first electrical coil and the second electrical coil are electrically energized,
• wherein the resultant magnetic field generated within the recharging envelope comprises a resultant magnetic field direction that renders irrelevant a positional angle θ (theta) of rotation of the third coil around the longitudinal axis extending between the first electrical coil and the second electrical coil with respect to a coupling efficiency of the level of the electrical current being induced in the third coil by the resultant magnetic field;
• and
• charging, by the electrical current induced in the third coil, the power source in the implantable medical device.