CUBIC uses four DC/DC converters. An Interpoint Model MLP2805SF/ES supplies +5V power for the CUBIC digital electronics. An Interpoint Model MLP2815DF/ES converter supplies +/-15V power to the CUBIC analog electronics. A high-efficiency variable voltage converter designed by Roland Green of our lab provides power to our TEC. Finally, +30V analog power for our CCD amplifier ( V actual) is supplied by a voltage doubler running off the +15V power. Power budgets and converter efficiencies are shown in Table 5.
Table 5: Power Budget and DC/DC Converter Efficiencies
The TEC power supply voltage is controlled by the ICP by moving the ``wipers'' on a digital potentiometer. Each pulse from the ICP moves the pot ``wiper'' one position in the positive or negative direction (where positive adjustments increase the TEC voltage). There are 100 positions in the pot. Sending more than 100 pulses leaves the pot at the end of its travel and does not damage it or roll its value over. The pot can be commanded from the ground via serial command SC38. We had intended to control the pot in a simple control loop via the ICP and housekeeping channels but did not have time to add this code to the flight software.