ABSTRACT
An implantable medical device is powered by a battery, which constitutes a severe limitation. In most cases, because of the battery discharge, the implanted system must be replaced through a surgical operation. The design of energy harvesters for implantable medical devices is usually more complicated than that for industrial applications. An implantable system must be biocompatible with tissues and cells of the environment in which it works. The analysis of the implantable systems has led to the definition of a classification according to the type of architecture; one class is telemetric systems and the second is self-powered systems. The implantable sensor measures the forces applied on the knee insert by several magnetoresistive force transducers which consist of magnetoresistors and permanent magnets. Implantable medical devices are widely employed in order to monitor or to control different physiological parameters. The telemetric and the energy-harvesting technique, especially the second one, represent valid alternative solutions to power an implantable medical device.
