A highly energy-efficient compressed sensing encoder with robust subthreshold clockless pipeline for wireless BANs

Compressed sensing is considered as a novel energy and bandwidth solution for wireless body area networks. In subthreshold operation, the conventional parallel structure is less energy-efficient than pipeline due to the low-frequency signals and the serious leakage energy. In this paper, we present a clockless pipeline compressed sensing encoder for highly energy-efficient purpose. Quasi-Delay-Insensitive circuits are introduced in the memory and the adder for improving the subthreshold robustness. The zero value detector in control units reduces the costs of computing power consumption and period. The full customized design is implemented in TSMC 65nm LP CMOS technology. Post-layout simulation results show that it can operate in the subthreshold supply voltage of 200mV. The most energy-efficient point is achieved as 109.8pJ at 300 mV. The max operation frequency ranges from 3KHz to 690KHz at 200mV to 600mV. For a fixed-throughput ECG signal, it improves 9.5× energy-efficiency compared with the parallel structure at 300mV and realizes minimum power consumption of 0.23μW at 200mV.