A High-Efficiency DC–DC Boost Converter for a Miniaturized Microbial Fuel Cell

This paper presents a high-efficiency dc-dc boost converter to interface a miniaturized 50 μL microbial fuel cell (MFC) having 1 cm² vertically aligned carbon nanotube anode and 1 cm² Cr/Au cathode. Geobacteraceae-enriched mixed bacterial culture in growth medium and 100 mM buffered ferricyanide solutions are used as the anolyte and catholyte, respectively. The miniaturized MFC produces up to approximately 10 μW with an output voltage of 0.4-0.7 V. Such low voltage, which is also load dependent, prevents the MFC to directly drive low power electronics. A pulse-frequency modulation type dc-dc converter in discontinuous conduction mode is designed and implemented to address the challenges and provides a load independent output voltage with high conversion efficiency. The fabricated dc-dc converter in UMC 0.18 μm has been tested with the MFC. At 0.9 V output, the converter has a peak efficiency of 85% with 9 μW load.