An ultra low power amplification and digitization system for neural signal recording applications
Sitong Yuan · SHAREOK (University of Oklahoma; Oklahoma State University; Central Oklahoma University) · 2010
Scope and Method of Study: The scope is to develop a tunable low power fully integrated band pass filter and a low power second order sigma-delta ADC modulator for implantable neural signal amplification and digitization applications, with subthreshold circuit design techniques in different CMOS processes. Since biopotentials usually contain low frequency components, the neural filters in this project have to be able to achieve large and predictable time constant for implantable applications. Voltage biased pseudo-resistors are vulnerable to process variations and circuit imperfections, and hence not suitable for implantable applications. A current biased pseudo-resistor is implemented in the neural filters in this work to set the cutoff frequency, and a Taylor series is used to study its linearity.