Design of an energy-autonomous, disposable, supply-sensing biosensor using bio fuel cell and 0.23-V 0.25-µm zero-Vth all-digital CMOS supply-controlled ring oscillator with inductive transmitter

An energy-autonomous, disposable supply-sensing biosensor based on bio fuel cells and a 0.23-V 0.25-µm zero-Vth all-digital CMOS supply-controlled ring oscillator with a current-driven pulse-interval-modulated inductive-coupling transmitter was demonstrated. All-digital and current-driven architecture using zero-Vth transistors enables low-voltage operation and small footprint in cost-competitive legacy CMOS. Measured results with 0.25-µm CMOS testchip successfully demonstrated operation under a 0.23-V supply, which is the lowest supply voltage among reported proximity transmitters. An energy-autonomous biosensing operation using organic bio fuel cells was also demonstrated.