A 0.5 mm2 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

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.