Digitally-Assisted Multi-input-Multi-output Power Converters for Radiation environments
When moving towards mobile applications, a strong need emerges for highly-efficient integrated power converters. A similar trend is observed in space applications, where a light weight and high power efficiency are key. Typically, the high voltage output power of a solar panel or battery needs to be down-converted to a usable voltage level to supply the electronics on-board. In space applications, however, an increased robustness is needed to overcome the increased radiation levels combined with high temperature swings. Apart from this, due to the total ionizing dose (TID), analog circuits as well as internal voltage references will tend to drift resulting in a decreased overall performance of the converter. Single Event Transients (SETs), on the other hand, can result in an unstable output voltage and instabilities in the control system. The purpose of this PhD is to investigate the possibilities of automatic reconfiguration and tuning of a DC-DC converter. This is needed to overcome the effects of Total Ionizing Doze (TID) on the analog blocks of the control system. In a first step, the impact of both TID and SETs on amplifiers and voltage references will be investigated. A digital tuning scheme for this blocks will be developed and tested (possibly using an fpga). Afterwards, the blocks will be combined in a digitally-assisted DC-DC converter with automatic tuning capabilities. Since circuits in radiation environments also suffer from SETs, this will also be taken into account during the implementation of the digital part. The ultimate goal of this PhD is to develop a fully-automatic digital tuning system for integrated DC-DC converters in radiation environments up to TID levels of 200 Mrad(Si). To support this, the ADVISE research group has a great expertise in simulation techniques for radiation hardness. Circuit simulations (spectre) will need to be combined with finite element simulations (synopsis sentaurus) en digital circuit simulation (Verilog). Furthermore, also an X-ray radiation facility as well as an annealing chamber is available to be used at measurement time. Last but not least, integrated circuits will also be investigated using the two-photon absorption laser facility to introduce SETs at specific nodes. This results in a detailed sensitivity map of the integrated circuit and an increased understanding of the radiation effects.