Patent ID: 7565204

Claim:
An implantable device capable of controlling received power from an external source comprising: a power receiving unit (PRU) adapted to receive power from an external power source by means of magnetic coupling to said external power source, said PRU comprising a resonant circuit comprising at least an inductor and a capacitor and wherein the external power source induces a time varying electrical signal in the inductor providing thereby a time varying PRU signal, said time varying electrical signal characterized as having zero voltage crossings; a load circuit coupled to the PRU and configured to receive power therefrom; a switch circuit interconnected between the PRU and the load circuit, the switch circuit adapted to interrupt the transfer of power from the PRU to the load circuit, wherein the switch circuit provides a short circuit connection across the PRU to thereby interrupt power transfer from the PRU to the load circuit; and a voltage comparator operatively coupled to the switch circuit and configured to monitor the voltage across the load circuit wherein the comparator circuit further comprises a zero voltage crossing detector whereby the comparator circuit causes the switch circuit to interrupt the power transfer from the PRU to the load circuit as a function of a detected zero voltage crossing.