A 2-Bit-Per-Cycle SAR ADC Prototype for Application in Biohybrid Systems Interfacing

The exploration of bioelectric action potentials within fungal mycelium networks has created new possibilities for the development of biohybrid systems for sensing and communication. With recent studies suggesting possible neuromorphic processing through distinct patterns of electrical spikes, the demand to interface with such networks increases. However, reliable capturing and processing of such signals due to their low frequency, amplitude, and noise susceptibility presents a significant engineering challenge; this work demonstrates a prototype of a successive approximation register analogue to digital converter designed to facilitate accurate data acquisition of biological signals. The proposed design is capable of resolving 2 bits per conversion cycle by employing a four-fully-differential-comparator scheme and dynamic voltage scaling, achieving higher bit rates without sacrifices in terms of power consumption or resolution. Initial FPGA-in-the-loop simulations demonstrate the concept's functionality setting the foundation for developing advanced biohybrid interface systems, thus supporting novel applications in the emerging fields of neuromorphic computing and environmental sensing.