Variance-based Digital Logic for Energy Harvesting Internet-of-Things

In this paper we propose a novel approach for designing digital circuits that uses the variance of a signal to represent Boolean logic levels. The variance-based logic (VBL) representation enables embedding of rectification and multiplication modules within the basic logic cells and unlike AC-coupled or energy-recovery logic circuits the proposed approach obviates the need for any phase synchronization. As a result, VBL representation can be used for designing low-latency digital circuits that are directly powered by a combination of energy transducers with different frequency and source impedance characteristics. We present some representative examples of VBL circuits that can be implemented in a standard CMOS process and we present measurement results from fabricated prototype.