A 0.5-mm2 Solar Cell-Powered Biofuel Cell-Input Biosensing System With LED Driving for Stand-Alone RF-Less Continuous Glucose Monitoring Contact Lens

This letter presents the first solar cell (SC)-powered biofuel cell (BFC)-input biosensing system with pulse interval modulation (PIM) and pulse density modulation (PDM) LED driving capability for continuous glucose monitoring (CGM) contact lenses featuring stand-alone RF-less operation. 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, powering and sensing components are separated, which reduces the power budget from SCs. The measured power of 28/144 nW at the PIM/PDM mode with a 0.31/0.39-V supply voltage can be managed by the on-lens SCs, enabling a fully stand-alone on-lens operation under office-room ambient light whose typical illumination intensity is 800–1600 lx.