A Highly Efficient Switched-Capacitor Voltage Boost Converter with Nano-Watt MPPT Controller for Low-Voltage Energy Harvesting

Toshihiro OZAKI  Tetsuya HIROSE  Takahiro NAGAI  Keishi TSUBAKI  Nobutaka KUROKI  Masahiro NUMA  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E99-A   No.12   pp.2491-2499
Publication Date: 2016/12/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E99.A.2491
Type of Manuscript: Special Section PAPER (Special Section on VLSI Design and CAD Algorithms)
energy harvesting,  DC-DC converter,  charge pump,  MPPT,  low-power,  

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This paper presents a fully integrated voltage boost converter consisting of a charge pump (CP) and maximum power point tracking (MPPT) controller for ultra-low power energy harvesting. The converter is based on a conventional CP circuit and can deliver a wide range of load current by using nMOS and pMOS driver circuits for highly efficient charge transfer operation. The MPPT controller we propose dissipates nano-watt power to extract maximum power regardless of the harvester's power generation conditions and load current. The measurement results demonstrated that the circuit converted a 0.49-V input to a 1.46-V output with 73% power conversion efficiency when the output power was 348µW. The circuit can operate at an extremely low input voltage of 0.21V.