Driving piezoelectric-transformer-based DC/DC converters using pulse density modulation

The trends in power DC/DC conversion are not only size and weight reduction together with a good efficiency; EMI and mass production are a must as well. In this context, piezoelectric transformers seem to be the ideal solution, since they allow higher switching frequencies (size and weight reduction) while also providing high efficiencies. Additionally, they are not magnetic devices, which facilitates mass production. Many possible control strategies for this type of converters have been presented during the last years. In this paper, a pulse density modulation (PDM) control strategy for a DC/DC converter based on a piezoelectric transformer is presented.