A. Romani, M. Dini, M. Filippi, M. Tartagni and E. Sangiorgi
Department of Electrical, Electronic, and Information Engineering “G. Marconi” and Advanced Research Center on Electronic Systems “E. De Castro”, University of Bologna, Via Venezia 52, 47521 Cesena FC, Italy
The increasing interest on pervasive sensor networks and the steady development of electronic devices with low power consumption motivates the research on electronic systems capable of harvesting energy from the surrounding environment. Currently, most energy harvesters can provide in practical cases an output power density of about 10–100 μW/cm3.1 In this scenario, mechanical vibrations, thermal gradients, and photovoltaics represent the most promising power sources for supplying portable low-power electronic equipment.
For a successful application, it becomes essential to efficiently convert such low levels of input power. In this context, electronic interfaces based on recent commercial discrete components provide a cost-effective and easily implementable solution. Notable examples are reported in Refs 2–5, where intrinsic current consumptions down to 1 μA or less are achieved. However, in order to keep consumption low, discrete electronics must necessarily implement simplified, and thus less efficient, control schemes. In addition, nonnegligible, power-hungry parasitics are unavoidable when connecting discrete ...