A 1.15μW 5.54mm<sup>3</sup> Implant with a Bidirectional Neural Sensor and Stimulator SoC utilizing Bi-Phasic Quasi-static Brain Communication achieving 6kbps-10Mbps Uplink with Compressive Sensing and RO-PUF based Collision Avoidance
Baibhab Chatterjee, Gaurav Kumar K, Mayukh Nath, Shulan Xiao, Nirmoy Modak, Debayan Das, Krishna Jayant, Shreyas Sen
Abstract
To solve the challenge of powering and communication in a brain implant with low end-end energy loss, we present Bi-Phasic Quasi-static Brain Communication (BP-QBC), achieving < 60dB worst-case channel loss, and ~41X lower power w.r.t. traditional Galvanic body channel communication (G-BCC) at a carrier frequency of 1MHz (~6X lower power than G-BCC at 10MHz) by blocking DC current paths through the brain tissue. An additional 16X improvement in net energy-efficiency (pJ/b) is achieved through compressive sensing (CS), allowing a scalable (6kbps-10Mbps) duty-cycled uplink (UL) from the implant to an external wearable, while reducing the active power consumption to 0.52μW at 10Mbps, i.e. within the range of harvested body-coupled power in the downlink (DL), with externally applied electric currents < 1/5th of ICNIRP safety limits. BP-QBC eliminates the need for sub-cranial interrogators, utilizing quasi-static electrical signals for end-to-end BCC, avoiding transduction losses.