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

TL;DR

This paper introduces an integrated circuit that harvests energy from finger touch capacitance changes, demonstrating practical energy collection and powering a simple oscillator, advancing wearable and touch-based energy harvesting technology.

Contribution

The paper presents a novel ASIC design that converts finger touch capacitance variations into usable energy, with experimental validation and a proof-of-concept application.

Findings

Harvested 320pJ of energy per touch cycle

Capable of powering a ring oscillator with frequency range 80Hz to 30kHz

Demonstrates feasibility of touch-based energy harvesting for low-power devices

Abstract

We present an integrated circuit capable of scavenging energy from repetitive changes in finger touch capacitance. A finger tapping on this ASIC generates a capacitive change of approximately 770pF. These changes feed into a charge-pump circuit which stores 320pJ of energy on a 1nF 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 which outputs a series of chirps with frequencies ranging from 80Hz to 30kHz as the storage capacitor voltage charges and discharges.