11nW Signal Acquisition Platform for Remote Biosensing

Abstract

This paper presents the design of an extremely lowenergy biosensing platform that utilizes voltage to time conversion and time-mode signal processing to sense and accommodate electrophysiological biosignals that will be later sent remotely using a simple and low power communication scheme. The electrode input is fed to a chain of monostable multivibrators used as analog-to-time converters, which create time pulses whose widths are proportional to the input signal. These pulses are transmitted to an external receiver by means of singlepulse harmonic modulation as the communication scheme, at a carrier frequency of 10 MHz. The platform is designed to be implemented in a standard 0.18 µm IC process with an energy dissipation per sample per channel of 42.72 pJ, including communication, operating from a supply voltage of 0.6V with an input referred noise of 12.3µVrms. The resulting SNR for OSR=256 is 35.19 dB, and the system's power consumption at a sampling and communication rate of 256 Hz is 10.94 nW.

A Chip Integrity Monitor for Evaluating Moisture/Ion Ingress in mm-Sized Single-Chip Implants

“…This way, the power consumption of the sensing platform could be radically reduced, as a single pixel is very power efficient, i.e., 0.97 nW and 33.01 µW are consumed for 0.6 V and 1.8 V operation, respectively. By coupling the presented pixel and time-mode measurement approach with an energy-efficient communication protocol such as single pulse harmonic modulation [42] as done in [43], it is both possible and feasible to create a monitoring unit for single-chip wirelessly powered or energy harvesting implants. In such a case, the distributed integrity sensing cells could be used to monitor the hermeticity of the chip in vivo.…”