Power Distribution for Spacecraft Payloads that Employ State of the Art Radiation Hardened Integrated Circuits 2006-01-3058

Recent advances in the state of the art of space-borne data processors and signal processors have occurred that present some unprecedented constraints relating to their power needs. Such processors include the class of multiprocessors providing computational capabilities in the billions of floating point operations per second. Processors of this type tend to require use of modern radiation tolerant or radiation hardened integrated circuits requiring very low voltage power supplies that place considerable challenge on power distribution and conversion within those processing payloads. The primary challenges are efficient conversion of power from the spacecraft power bus to these low voltages and distribution of the very high accompanying currents within the payload while maintaining proper voltage regulation (typically +/− 5%). Some integrated circuits require 10 Amps or more at 1Volt, as an example [3], [6]. With multiple integrated circuits typically housed on a single subassembly board, and multiple boards in a payload, resultant current requirements (as high as 100 Amps) make distribution of such low voltages within a payload untenable due to simple IR drops and conductor sizes that would be needed. This paper discusses these challenges and some solutions that have been recently employed to overcome them within a payload (user equipment) using a form of distributed power system.