Fully-Integrated Reconfigurable Charge Pump with Two-Dimensional Frequency Modulation for Self-Powered Internet-of-Things Applications

Hao Chung Cheng, Wen Yuan Tsai, Po Han Chen, Po Hung Chen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

In this paper, we propose a fully-integrated reconfigurable charge pump in a 0.18-μm CMOS process; this converter is applicable for self-powered Internet-of-Things applications. The proposed charge pump uses a two-dimensional frequency modulation technique, which combines both the pulse-frequency modulation (PFM) and pulse-skip modulation (PSM) techniques. The PFM technique adjusts the operating frequency of the converter according to the variations in the load current, and the PSM technique regulates the output voltage. The proposed two-dimensional frequency modulation technique can improve the overall power conversion efficiency and the response time of the converter under light load conditions. A photovoltaic cell was chosen as the input source of the proposed converter. To adapt to the variations in the output voltage of a photovoltaic cell under different light illumination intensities, we built a reconfigurable converter core with multiple power conversion ratios of 2, 2.5, and 3 for the regulated output voltage of 1.2 V when the input voltage ranged from 0.53 V to 0.7 V. Our measurement results prove that the proposed capacitive power converter could achieve a peak power conversion efficiency of 80.8%, and the efficiency was more than 70% for the load current that ranged from 10μA to 620μA.

Original languageEnglish
Article number9162472
Pages (from-to)4132-4141
Number of pages10
JournalIEEE Transactions on Circuits and Systems I: Regular Papers
Volume67
Issue number11
DOIs
StatePublished - Nov 2020

Keywords

  • Charge pump
  • Internet-of-Things (IoT)
  • pulse-frequency modulation
  • pulse-skip modulation
  • reconfigurable
  • two-dimensional frequency modulation

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