A Fully Integrated RF-Powered Energy-Replenishing Current-Controlled Stimulator

Sohmyung Ha, Chul Kim, Jiwoong Park, Gert Cauwenberghs, Patrick P. Mercier

Research output: Contribution to journalArticlepeer-review


This paper presents a fully-integrated current-controlled stimulator that is powered directly from on-chip coil antenna and achieves adiabatic energy-replenishing operation without any bulky external components. Adiabatic supply voltages, which can reach a differential range of up to 7.2 V, are directly generated from an on-chip 190-MHz resonant LC tank via a self-cascading/folding rectifier network, bypassing the losses that would otherwise be introduced by the 0.8 V system supply-generating rectifier and regulator. The stimulator occupies 0.22 mm2 in a 180 nm silicon-on-insulator process and produces differential currents up to 145 \muA. Using a charge replenishing scheme, the stimulator redirects the charges accumulated across the electrodes to the system power supplies for 63.1% of stimulation energy recycling. To benchmark the efficiency of stimulation, a figure of merit termed the stimulator efficiency factor (SEF) is introduced. The adiabatic power rails and energy replenishment scheme enabled our stimulator to achieve an SEF of 6.0.

Original languageEnglish (US)
Article number8537908
Pages (from-to)191-202
Number of pages12
JournalIEEE Transactions on Biomedical Circuits and Systems
Issue number1
StatePublished - Feb 2019


  • Adiabatic stimulation
  • brain initiative
  • electrocorticography
  • neural stimulation
  • neural technology
  • neuromodulation

ASJC Scopus subject areas

  • Biomedical Engineering
  • Electrical and Electronic Engineering


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