Colorado Power Electronics is in the process of completing NASA SBIR contract NNC07CA12C Wide Output Range Power Processing Unit for Electric Propulsion. At the end of the project, we will have a complete brassboard PPU except for the Digital Control and Interface Unit (DCIU) and Flow Control Driver. The brassboard PPU meets the electrical requirements of the project, but the specific mass is about 20% too low compared to the first bullet of the solicitation. Preliminary results from testing a 4 kW discharge supply show that the full-power efficiency ranges from 94% to 96%. This proposal is to: (1) Determine ways to reduce the mass of the brassboard PPU (2) Evaluate the brassboard PPU to determine robustness improvements to be implemented in Phase II. (3) Determine requirements for a DCIU to be implemented in Phase II. (4) Design and build a brassboard Flow Control Driver (5) Gain experience in controlling gas flow The Flow Control Driver will be designed to control a xenon gas flow system selected by NASA. The DCIU design will be based on requirements received from NASA. The significance of this project is that it makes improvements to an innovative and promising PPU technology, moving it closer to a flight-ready product, while also facilitating NASA research with advanced flow controls.