Impact-based piezoelectric energy harvester as a power source for a neural activity monitoring circuit

Recently, energy harvesters have been studied as a power source for implantable biomedical devices. However, practical applications of energy harvesters to implantable medical devices are very rare because energy harvesters and implantable medical devices have been studied separately. In this paper, we present a neural activity monitor circuit, which is one of implantable medical devices, solely powered by an energy harvester. The system consists of an impact-based piezoelectric energy harvester, a power transfer circuit, and a neural signal monitoring circuit. Reliability of the system was verified by comparing it with a system powered by a DC power supply. It was found that the harvester provided sufficient energy to the system for reliable neural activity monitoring. We expect that presented results may work as a reference for designing harvesters and power transfer circuits together with implantable medical devices in an environment of a human body.