Self-synchronized Rectifier with Phase Information Extracted from Vibration Energy Harvester

Low-loss rectification is essential for vibration energy harvesters. However, an extremely low loss is difficult to achieve in rectification using diodes due to the voltage drop caused by the threshold voltage of the diodes. Although synchronous rectification using transistors can avoid the voltage drop, it requires active control of the transistor gates. In this study, we achieved selfsynchronized rectification using only passive elements by switching the transistors by separately extracting the phase information from a vibration energy harvester. The operation of the selfsynchronized rectifier was demonstrated through simulations and experiments and was compared with that of a diode bridge. In addition, it was clarified that the self-synchronized rectifier is limited by the through current generated between the output terminals during switching and that the through current determines the lower limit of the power that can be rectified by this circuit. These results demonstrate a typical example where the performance trade-off of a power circuit can be addressed by co-designing the harvester device and the power circuit.