100 nA power management circuit for energy harvesting devices

This paper presents a power management circuit suitable for energy harvesting devices. Energy harvesting methods provide very low instantaneous power which is not sufficient to continuously power a wireless sensor node. Presented power management circuit is designed to turn on the wireless sensor node when the voltage across storage capacitor reaches 5 V and turns it back off as the voltage drops to 4.5 V. In such operating conditions maximal current that power management circuit draws is under 100 nA. Laboratory model of a power management circuit is realized and the performance measurements for various inputs were conducted. Additionally, a mathematical model of the power management circuit is derived and compared with measurement results.