Integrated Three-Level Flying Capacitor DC-DC Buck Converter for CubeSat Applications

In this work, the design, simulation and implementation of a DC-DC buck converter based on the Three-level Flying Capacitor Converter architecture for space applications, namely CubeSat systems, using the Skywater 130nm CMOS technology is presented. The power circuits are fully integrated on-chip, including the power MOSFETs and the gate drivers, to obtain an efficient and compact implementation. This versatile power electronics building block, is also a contribution to the open source IC design community. Additionally, tests structures for the flying capacitor and the output filter inductors are included to characterize the technology passive. The active area of the dual-core circuit (including power switches and drivers) occupies less than 1mm2 of silicon in this process. Simulated results shows a peak efficiency of 87% at 140mA load current for the single core converter, and a peak efficiency of 93.3% at 555mA load current for the dual-core converter, at 1MHz switching frequency. It also shows a 85% peak efficiency for full on-chip flying capacitor single-core implementation at 10MHz operation.