Charge-pumping with finger capacitance in a custom electrostatic energy harvesting ASIC

Abstract

We present an integrated circuit capable of scavenging energy from repetitive changes in finger touch capacitance. A finger tapping on this application-specific integrated circuit generates a capacitive change of approximately 770 pF. This change feeds into a charge-pump circuit that stores 320 pJ of energy on a 1 nF storage capacitor. We present measurement results and simulations that demonstrate operation. As a proof-of-concept, we also demonstrate that the harvested energy can power a ring oscillator that outputs a series of chirps with frequencies ranging from 80 Hz to 30 kHz as the storage capacitor voltage charges and discharges.