Abstract: The present invention consists in a method implemented in a computer for the numerical simulation of a semiconductor device which contains (a) tunnel junctions and allows the simulation for all the working range of the tunnel junction. The method is based on a distributed model where the tunnel junction can be integrated in the simulation by means of distributed electronic circuits of a semiconductor device and, specially, of a multijunction solar cell. The said method is used to circumvent the convergence problem existing so far and allows in particular the full description of the experimental behavior of the multijunction solar cells and, by extension, of any kind of semiconductor device containing tunnel junctions.

Abstract: An energy supply system for implantable medical devices generates an energy supply by a photovoltaic converter which transforms the light coming from outside of the body. The light is carried to the converter by an optical fiber. This system allows the implanted devices to work without the time restrictions of batteries and opens the door to the development of new devices with much higher power ratings. The system includes a light source (1) external to the patient's body, an optical fiber (3) which runs from a point on the surface of the patient to the implantable device (4) and a photovoltaic converter (5) placed inside the device where the optical fiber ends. Finally, a power conditioning stage (6) ensures that the electrical power generated suits the needs of the other components (7) of the implantable device.