The Atmosphere-Space Interactions Monitor (ASIM) aboard ISS was proposed for studying the high-altitude, thunderstorm-related optical emission from the stratosphere and mesosphere. One of the two main instruments in ASIM is the Miniature-X and Gamma-ray Sensor (MXGS) designed by the University of Bergen and University of Valencia in cooperation with Polish CBK PAN in Warsaw. The CBK PAN was responsible for designing and manufacturing the Power Supply Unit and its autonomous (FPGA based) Housekeeping System.