A Low-Power, Single-Chip Electronic Skin Interface for Prosthetic Applications

A low-power, single-chip electronic skin interface is presented. The system on chip (SoC) implementation significantly reduces the physical footprint and power requirements compared to commercial interfaces, which enables the creation nimble prosthetic limbs. Its small size and reduced battery requirements are ideal for advanced prosthetics that utilize electronic skin to provide their user tactile feedback. The architecture consists of multiple charge-sensitive analog front ends (AFEs) interfaced to a central, 16-bit microcontroller core which is capable of processing the sensory information in real time. Event-driven operation allows the chip to monitor all input channels while consuming minimal energy. A test chip has been fabricated in a 0.13$\mu$m CMOS technology and its functionality demonstrated by interfacing the chip to a prototype electronic skin based on polyvinylidene fluoride (PVDF) piezoelectric sensors. Tactile signals from the sensors are measured and processed on-chip to calculate the corresponding charge. This is accomplished by programming the microcontroller with a custom software algorithm, granting the system the flexibility to interface to different types of sensors. The single-chip electronic skin system consumes 7.0 ${\mu {\rm W}}$ per channel and 93.5 ${\mu {\rm W}}$ in the example application when stimulated at 1Hz, making it suitable for use with battery-powered prosthetics.