A 13.56-MHz Wireless Power Transfer System With Enhanced Load-Transient Response and Efficiency by Fully Integrated Wireless Constant-Idle-Time Control for Biomedical Implants

Cheng Huang, Toru Kawajiri, Hiroki Ishikuro

Research output: Contribution to journalArticle

7 Citations (Scopus)


In this paper, a complete wireless power transfer system with transmitter (TX) and receiver (RX) chips is presented. Both RX local and TX wireless output voltage regulations are achieved by the proposed constant-idle-time control without using any wires or additional discrete components, such as MCU, DAC, various kinds of controllers, and decoders, which were required in previous works. The system and circuitry design complexity is significantly reduced. Both TX and RX chips are fabricated in the TSMC 65-nm process with standard 2.5-V I/O devices, and the RX coil is fabricated using flexible printed circuits to demonstrate the performance for implantable applications. Up to 17.5% end-to-end total efficiency improvement is observed when enabling the wireless constant-idle-time controlled TX voltage regulation, and an instant load-transient response is also achieved. As a result, compared to previous works, this design achieves a higher total efficiency, a faster load-transient response, and a higher level of integration with a much lower system and circuitry design complexity.

Original languageEnglish
JournalIEEE Journal of Solid-State Circuits
Publication statusAccepted/In press - 2017 Nov 21



  • Backscattering
  • Batteries
  • biomedical implants
  • Complexity theory
  • constant-idle-time
  • efficiency
  • flexible printed circuits (FPCs)
  • full integration
  • Implants
  • load-transient response
  • Resonant frequency
  • Voltage control
  • voltage regulation
  • Wireless communication
  • wireless power transfer (WPT)
  • Wireless sensor networks

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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