A switched-capacitor voltage regulator for ultra-low power energy harvesting systems

In this paper, an SC voltage doubler-based voltage regulator for ultra-low power energy harvesting applications is presented. It produces a stable 1.2-V power supply, using inputs from 0.63 V to 1.8 V. External compensation and on-chip output capacitor ensure good performance even with zero load current and any load capacitance. The regulator tolerates arbitrary input ramp-ups, and is immune to blackout and brownout. The regulator ASIC is implemented in a 0.18 μm CMOS process. The measured regulator peak power and current efficiency are 63 % (ideal: 80 %) and 49 % (50 %), respectively. The performance has been characterized with load currents from zero to 100 μA.