A Hybrid-Integrated Artificial Mechanoreceptor in 180nm CMOS

A low-power wireless chip for an implantable tactile sensor system is presented. The reported ASIC utilizes the low-loss magnetic human body communication channel for both wireless powering and data transfer. The chip is hybrid-integrated with an in-house fabricated MEMS capacitive force sensor to form an implantable artificial mechanoreceptor (IAM). An on-chip correlated double sampling capacitance-to-time converter consumes 3.9μW from a 1.2V on-chip regulated supply and achieves a resolution of 22.8fF over an input capacitance range of 100pF, while occupying an area of only 0.04mm
²
. A wireless power management feedback is used to ensure robust operation for different hand gestures and under process-voltage-temperature (PVT) variations. The IAM can operate in on-off keying (OOK) or frequency-shift keying (FSK) modulation formats, where the transmitter consumes only 15.6μW in OOK mode and is more immune to hand gesture variations in FSK mode. The 1.62mm
²
chip is fabricated in a standard 180nm CMOS process and consumes 104.3μW.