A 0.6 V, 1.66mW energy harvester and audio driver for tympanic membrane transducer with wirelessly optical signal and power transfer

An energy harvester and ultra-low-voltage audio driver to mechanically stimulate tympanic membrane (TM) transducer is presented. By wirelessly optical signal and power transfer, the audio driver is able to directly drive the actuator on the TM to improve sound quality while avoiding occlusion effects. The measured THD+N is 0.4% over the audio bandwidth with modulation index of 0.4, and maximum power conversion efficiency is 24.7%. The core circuits dissipate 1.66mW from 0.6 V through optical power transfer. Fabricated in TSMC 90 nm CMOS technology, the chip size is 0.88×0.84mm2.