Patent ID: 6212431
Filing Date: 2001-04-03
Classification: A61N

Abstract:
An external power coupling system for optimally coupling power to an implantable device at a fixed frequency, the implantable device having an input impedance that varies as a function of implant distance and implant load, the power coupling system comprising:eternal driver means for generating an ac power signal at a fixed frequency;an external coil for receiving the ac power signal and inductively coupling the ac power signal to the implantable device;an impedance matching circuit interposed between the external coil and external driver means for setting an output impedance of the power coupling system, the impedance matching circuit having means for adjusting the output impedance as a function of a control signal;directional coupler means coupled to the ac power signal for sensing reverse power;signal processing means for generating the control signal as a function of the sensed reverse power, and applying the control signal to the impedance matching circuit so as to adjust the output impedance to match the input impedance of the implantable device.