Low-Power Interface IC for Triplate Electrostatic Energy Converters

This letter proposes a low-power energy harvesting circuit (EHC) that performs synchronous energy conversion on a triplate variable capacitor to improve the maximum achievable output power. A triplate macro-scale electrostatic generator with capacitor variation of 405 pF to 1.15 nF and 405 pF to 1.07 nF on two complementary adjacent capacitors operating 180° out of phase at 98 Hz is fabricated and used in the characterization of the designed EHC. The integrated circuit is fabricated using AMI 0.7-μM high-voltage CMOS process and tested with the triplate capacitor to demonstrate mechanical to electric energy conversion. At steady state, the EHC produces 3.26 nJ/cycle, including energy flyback losses. This results in a total output power of approximately 308 nW on a 10-μF reservoir capacitor from a 98-Hz vibration signal.