A Wireless Artificial Mechanoreceptor in 180-nm CMOS

This article presents an implantable low-power wireless integrated system for tactile sensing applications. The reported ASIC utilizes a low-loss magnetic human body communication channel for both wireless power and data transfer. The chip is hybrid-integrated with an in-house fabricated MEMS capacitive force sensor to form an implantable artificial mechanoreceptor. An on-chip correlated double sampling capacitance to time converter consumes 750nW from a 1.2V on-chip regulated supply, achieving a 2.0fF resolution for an input capacitance of 14pF and a FoM of 49 fJ/c-s while occupying an area of only 0.04 mm². The capacitance to time converter has a time-multiplexed mode to interface with 4 input capacitors. Wireless power management feedback is utilized to ensure robust operation in the presence of hand gesture changes and process-voltage-temperature variations. The on-chip data transmitter can operate in on-off keying or frequency-shift keying modulation formats, where it consumes only 7.8 $$ in the on-off keying mode. The 1.62mm² chip is fabricated in a standard 180nm CMOS process and consumes 110.3 $$ .