TET system for implanted medical device

摘要

A TET system is operable to vary an amount of power transmitted from an external power supply to an implantable power unit in accordance with a monitored condition of the implantable power unit. The amount of power supplied to the implantable power unit for operating a pump, for example, can be varied in accordance with a cardiac cycle, so as to maintain the monitored condition in the power circuit within a desired range throughout the cardiac cycle.

主权项

1. A circulatory assist device comprising:
(a) a pump adapted for implant in a patient, the pump having an electric motor, the pump having a time-varying power demand which is adapted to vary with a cardiac cycle of the patient; (b) an implantable power unit adapted for mounting within a body of the patient, the implantable power unit having a secondary coil, a power circuit connected to the secondary coil for supplying power to the pump so that power applied to the secondary coil can be transmitted to the pump, and a monitoring circuit operable to monitor a condition of the power circuit and to send a transcutaneous telemetry signal representing the monitored condition, (c) an external power supply having a primary coil adapted for transcutaneous inductive coupling with the secondary coil, a drive circuit operable to apply an alternating current to the primary coil, and a control circuit operable to receive the telemetry signal and to adjust the alternating current in the primary coil at least in part in response to the telemetry signal, the monitoring circuit and control circuit being operable to monitor the condition of the power circuit and to vary an amount of the power applied to the secondary coil in accordance with the time-varying power demand of the pump in intervals of less than one second of a plurality of periodic intervals during the cardiac cycle, wherein the control circuit is operable to adjust the alternating current in the primary coil at a sufficient rate such that the implantable power unit can supply power to the pump without drawing power from an implanted battery.