[14p-F204-1~15] 12.7 Biomedical Engineering and Biochips

▼ [14p-F204-6] CMOS-based Optical Energy Harvesting Circuit for Bio-implantable and IoT Devices

〇(M2)Nattakarn Wuthibenjaphonchai¹, Makito Haruta¹, Toshihiko Noda¹, Kiyotaka Sasagawa¹, Takashi Tokuda¹, Jun Ohta¹ (1.Nara Institues of Science and Technology)

Keywords:Energy harvesting, Wireless

Due to rising demands for wirelessly-operated implantable device, wireless energy harvesting from ambient energy source is essential. In general, current and voltage obtained by the ambient energy source such as solar energy are limited and not sufficient to operate the target circuit continuously. So this research aims to design a CMOS (Complementary metal–oxide–semiconductor)-base optical energy harvesting chip that accumulates small optically-transferred electric power and intermittently supplies power to a target device. The basic circuit of optical energy harvesting circuit, which includes an external capacitor, a voltage detector, a bias circuit and a CMOS switch, was designed to realize energy accumulation and intermittent operation. Then, we use the basic circuit to design a two-stage energy harvesting circuit which generates a sufficient supply voltage and a clock signal that means the circuit can operate a clock-driven target circuit. The chip also contains an optical ID circuit that can be operated environmental or intentional illumination and send back the device’s ID using two LEDs. The power supply and clock signal from the designed optical energy harvesting chip is controlled by adjusting the bias voltages level. We evaluated the circuit and confirmed that the circuit correctly works as an optically driven optical ID device.