A Triple-Loop Inductive Power Transmission System for Biomedical Applications

Byunghun Lee, Mehdi Kiani, Maysam Ghovanloo

    Research output: Contribution to journalArticlepeer-review

    73 Scopus citations

    Abstract

    A triple-loop wireless power transmission (WPT) system equipped with closed-loop global power control, adaptive transmitter (Tx) resonance compensation (TRC), and automatic receiver (Rx) resonance tuning (ART) is presented. This system not only opposes coupling and load variations but also compensates for changes in the environment surrounding the inductive link to enhance power transfer efficiency (PTE) in applications such as implantable medical devices (IMDs). The Tx was built around a commercial off-the-shelf (COTS) radio-frequency identification (RFID) reader, operating at 13.56 MHz. A local Tx loop finds the optimal capacitance in parallel with the Tx coil by adjusting a varactor. A global power control loop maintains the received power at a desired level in the presence of changes in coupling distance, coil misalignments, and loading. Moreover, a local Rx loop is implemented inside a power management integrated circuit (PMIC) to avoid PTE degradation due to the Rx coil surrounding environment and process variations. The PMIC was fabricated in a 0.35-μm 4M2P standard CMOS process with 2.54 mm2 active area. Measurement results show that the proposed triple-loop system improves the overall PTE by up to 10.5% and 4.7% compared to a similar open- and single closed-loop system, respectively, at nominal coil distance of 2 cm. The added TRC and ART loops contribute 2.3% and 1.4% to the overall PTE of 13.5%, respectively. This is the first WPT system to include three loops to dynamically compensate for environment and circuit variations and improve the overall power efficiency all the way from the driver output in Tx to the load in Rx.

    Original languageEnglish (US)
    Article number7031455
    Pages (from-to)138-148
    Number of pages11
    JournalIEEE transactions on biomedical circuits and systems
    Volume10
    Issue number1
    DOIs
    StatePublished - Feb 2016

    All Science Journal Classification (ASJC) codes

    • Biomedical Engineering
    • Electrical and Electronic Engineering

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