Charge recovery logic for thermal harvesting applications

This paper investigates the substitution of CMOS or near-threshold CMOS with Charge Recovery Logic (CRL) in applications where energy is thermally harvested. By doing so, it is possible to eliminate the bulky DC/DC stage needed to provide the supply voltage for CMOS operation. Instead, a simple LC-tank oscillator is used to generate a power-clock suitable for CRL operation. Simulation results of a 256-stage inverter chain designed in Efficient Charge Recovery Logic (ECRL) are presented. Two additional novelties are presented i) using ECRL at a near-threshold voltage and ii) generating the four-phase power-clock by means of a quadrature oscillator. The traditional, full-swing CMOS system dissipates 18.2× the power dissipated by the proposed TP-ECRL system.