Patent ID: 7062331

Claim:
A first side energy transfer system for transferring power from a power supply having a primary winding located on a first side of a physical boundary to a variable load having a secondary winding located on a second side of the physical boundary over a power channel created between the primary and secondary windings, the first side energy transfer system comprising: a primary winding electrically coupled to the power supply to generate a magnetic field based on input power provided by the power supply, the magnetic field permeating the physical boundary for magnetically coupling a secondary winding to the primary winding to form a power channel to provide power to a variable load; an excitation control circuit coupled to the primary winding to detect on the primary winding an indication of at least one of changes in a variable load and changes in the relative position of the primary winding and a secondary winding; and a primary control circuit electrically coupled to the primary winding and to the excitation control circuit to regulate a primary voltage across the primary winding based on the detected indication for providing a sufficiently stable output power to the variable load notwithstanding at least one of changes in a load and changes in a relative position of the primary winding and a secondary winding; wherein the excitation control circuit includes a rectifier coupled to the primary winding and a comparator coupled to the rectifier that compares a voltage in the primary windimg to a threshold voltage, wherein the rectifier at least partially rectifies the primary voltage for comparison with the threshold voltage by the comparator.