A 92%-Efficiency Inductor-Charging Switched-Capacitor Stimulation System With Level-Adaptive Duty Modulation and Offset Charge Balancing

Kyeongho Eom, Han Sol Lee, Minju Park, Seung Min Yang, Jong Chan Choe, Suk Won Hwang, Young Woo Suh, Hyung Min Lee

    Research output: Contribution to journalArticlepeer-review

    3 Citations (Scopus)

    Abstract

    This article proposes an inductor-charging switched-capacitor stimulation (iSCS) system capable of high-efficiency capacitor charging and high-efficacy decaying exponential stimulation. The iSCS system adopts a fast inductor-based charger with level-adaptive duty modulation and charging range detection that can efficiently charge capacitors from any residual voltage levels to the target voltages up to 3 V. The offset-control charge balancing (OC-CB) adaptively reduces the mismatch between cathodic and anodic charges. The iSCS prototype can charge 1-mu text{F} capacitor from 0 V (1.5 V) to 3 V within 50 μs (28μs), achieving 90% (92.7%) capacitor charging efficiency. The iSCS system efficiency was measured up to 92%, which is >10% higher than state-of-the-art works. The iSCS also achieved higher stimulus efficacy thanks to its decaying exponential waveform. In vivo experiments for ocular muscle stimulation using the iSCS system resulted in a 20% increase in eye movement distance while consuming 13% less energy compared to the current-controlled stimulation system. This ensures higher system efficiency and enhanced stimulus efficacy.

    Original languageEnglish
    Pages (from-to)1521-1531
    Number of pages11
    JournalIEEE Journal of Solid-State Circuits
    Volume59
    Issue number5
    DOIs
    Publication statusPublished - 2024 May 1

    Bibliographical note

    Publisher Copyright:
    © 1966-2012 IEEE.

    Keywords

    • Capacitor charger
    • implantable medical devices
    • muscular stimulation
    • offset-control charge balancing (OC-CB)
    • switched-capacitor stimulation (SCS)

    ASJC Scopus subject areas

    • Electrical and Electronic Engineering

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