A 0.5 mm<sup>2</sup> 0.31 V/0.39 V 28 nW/144 nW 65 nm CMOS Solar Cell-Powered Biofuel Cell-Input Biosensing System with PIM/PDM LED Driving for Stand-Alone RF-Less Continuous Glucose Monitoring Contact Lens
Guowei Chen, Xinyang Yu, Yue Wang, Tran Minh Quan, Naofumi Matsuyama, Takuya Tsujimura, Md. Zahidul Islam, Kiichi Niitsu
Abstract
This work presents the first solar cell (SC)-powered biofuel cell (BFC)-input biosensing system with hybrid pulse interval modulation (PIM) and pulse density modulation (PDM) LED driving capability for stand-alone RF-less continuous glucose monitoring (CGM) contact lenses, which allows diabetes patients to obtain CGM level information without any external devices. Power supply from on-lens SCs can eliminate the necessity of wireless power delivery, and LED implementation can eliminate the necessity of wireless communication. By employing the BFC-input approach instead of using a power-hungry potentiostat, power consumption was reduced. The measured power of 28 nW/144 nW at PIM/PDM mode with a 0.31 V/0.39 V supply voltage can be managed by the on-lens SCs, enabling a fully stand-alone operation under office-room ambient light.