Alphacore Inc. will develop a low-profile, lightweight, high efficiency, mixed-signal (analog/digital) controlled Isolated DC-DC converter that helps address NASA’s demand for Innovative Ways to Transmit Power over Long Distances for Lunar and Mars Missions, including “applications of wide-bandgap electronics in direct current (DC)-to-DC isolating converters with wide-temperature, high-power-density, high-efficiency, power electronics and associated drivers for voltage regulation”.
The developed converter will have a reduced component count, enabling reduced failure modes, lower PCB area and it includes over voltage protection, fault tolerance, load monitoring, and allows control and status monitoring by a remote power system controller. This solution includes all controller circuitry and drivers integrated in a single CMOS ASIC chip, as well as the GaN-based DC-DC converter’s power stage.
Alphacore’s converter will utilize CMOS based drivers and controllers for the GaN power stage. The driver and controller would be based on X-FAB’s latest XT018 process, a 0.18 µm modular high-voltage SOI technology. It combines the benefit of conventional SOI wafers with Deep Trench Isolation (DTI), those of a state-of-the-art six metal layers 0.18 µm process, and localized partial SOI for unique high-voltage super-junction (SJ) power transistors. Unlike traditional high-voltage LDMOS devices from conventional bulk or SOI CMOS processes, the unique high-voltage SJ DMOS power transistors with VDS breakdown voltage of 100V, 140V and 200V offered in XT018 have reduced conduction loss (RDS) with the same silicon area, such that lower FOM (RDS∙Qgd) is available for higher efficiency applications. The planar high-voltage SJ DMOS transistor also has significantly better radiation tolerance for both TID effects and SEE. In addition, the low-voltage CMOS devices (which we will use for the controller design) in this process are extremely radiation tolerant.
Our DC-DC converter solution will contribute greatly to NASA's Watts on the Moon Surface Challenge and other space applications, e.g., Artemis program; Lunar Gateway. This solution allows more technological functions to fit within less volume, operational in the ranges: 153 to 123 °C for lunar applications and -125 to 80 °C for Mars bases. Alphacore’s solution will be radiation-hardened and integrated to provide a single-package solution. This converter prototype will undergo the best known relevant environmental testing.
Defense and commercial space applications also benefit from this solution. The proposed converter has potential commercial applications in the space electronics market sector due to its high radiation hardness, high input voltage, high efficiency, high output current and compact size. The rise in demand for industrial robots is expected to also be a significant driver to the commercial market.