An automatic protection of spacecraft high power lines: the electronic solid state switch (ELS3)

This paper describes the principle and preliminary performances of an electronic solid state switch (ELS³). The objective is to provide an automatic protection device for the automatic and reliable protection of the high power lines in a space craft, bearing in mind the replacement of mechanical relays and fuses. The principle lies in the use on the one hand of the MOSFET technology which allows reliable paralleling of components for high current combined with a self-thermal protection during transient overstress, and on the other hand the implementation of an active thermal control system which maintains the crystal temperature of the chips inside acceptable limits. A parametric study at component level is detailed as well as the simulation of the ESACAP computer program of the thermal behaviour of a thick film power stage. Breadboard measurements end this study.