An integrated power-efficient active rectifier with offset-controlled high speed comparators for inductively powered applications

Hyung Min Lee, Maysam Ghovanloo

Research output: Contribution to journalArticlepeer-review

143 Citations (Scopus)

Abstract

We present an active full-wave rectifier with offset-controlled high speed comparators in standard CMOS that provides high power conversion efficiency (PCE) in high frequency (HF) range for inductively powered devices. This rectifier provides much lower dropout voltage and far better PCE compared to the passive on-chip or off-chip rectifiers. The built-in offset-control functions in the comparators compensate for both turn-on and turn-off delays in the main rectifying switches, thus maximizing the forward current delivered to the load and minimizing the back current to improve the PCE. We have fabricated this active rectifier in a 0.5-μm 3M2P standard CMOS process, occupying 0.18mm2 of chip area. With 3.8 V peak ac input at 13.56 MHz, the rectifier provides 3.12 V dc output to a 500 Ω load, resulting in the PCE of 80.2%, which is the highest measured at this frequency. In addition, overvoltage protection (OVP) as safety measure and built-in back telemetry capabilities have been incorporated in our design using detuning and load shift keying (LSK) techniques, respectively, and tested.

Original languageEnglish
Article number5705523
Pages (from-to)1749-1760
Number of pages12
JournalIEEE Transactions on Circuits and Systems I: Regular Papers
Volume58
Issue number8
DOIs
Publication statusPublished - 2011

Keywords

  • Active rectifier
  • RFID
  • back telemetry
  • high speed comparators
  • implantable microelectronic devices
  • inductive power transmission
  • load shift keying
  • offset control

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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