A Light-Tolerant Wireless Neural Recording IC for Motor Prediction With Near-Infrared-Based Power and Data Telemetry
Jongyup Lim, Jungho Lee, Eunseong Moon, Michael Barrow, Gabriele Atzeni, Joseph G. Letner, Joseph T. Costello, Samuel R. Nason, Paras R. Patel, Yi Sun, Parag G. Patil, Hun-Seok Kim, Cynthia A. Chestek, Jamie Phillips, David Blaauw, Dennis Sylvester, Taekwang Jang
Abstract
Miniaturized and wireless near-infrared (NIR)-based neural recorders with optical powering and data telemetry have been introduced as a promising approach for safe long-term monitoring with the smallest physical dimension among state-of-the-art standalone recorders. However, the main challenge for the NIR-based neural recording integrated circuits (ICs) is to maintain robust operation in the presence of light-induced parasitic short-circuit current from junction diodes. This is especially true when the signal currents are kept small to reduce power consumption. In this work, we present a light-tolerant and low-power neural recording IC for motor prediction that can fully function in up to 300 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{W}$ </tex-math></inline-formula> /mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> of light exposure. It achieves the best-in-class power consumption of 0.57 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{W}$ </tex-math></inline-formula> at 38 °C with a 4.1 noise efficiency factor (NEF) pseudo-resistor-less amplifier, an on- chip neural feature extractor, and individual mote-level gain control. Applying the 20-channel pre-recorded neural signals of a monkey, the IC predicts finger position and velocity with a correlation coefficient up to 0.870 and 0.569, respectively, with individual mote-level gain control enabled. In addition, wireless measurement is demonstrated through optical power and data telemetry using a custom photovoltaic (PV)/light-emitting diode (LED) GaAs chip wire bonded to the proposed IC.