Design of Switched-Capacitor Voltage Boost Converter for Low-Voltage and Low-Power Energy Harvesting Systems

Tetsuya HIROSE  Yuichiro NAKAZAWA  

IEICE TRANSACTIONS on Electronics   Vol.E103-C   No.10   pp.446-457
Publication Date: 2020/10/01
Publicized: 2020/05/20
Online ISSN: 1745-1353
DOI: 10.1587/transele.2019CTI0002
Type of Manuscript: INVITED PAPER (Special Section on Analog Circuits and Their Application Technologies)
Category: Electronic Circuits
Internet of Things (IoT),  energy harvesting,  voltage boost converter,  output impedance,  

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This paper discusses and elaborates an analytical model of a multi-stage switched-capacitor (SC) voltage boost converter (VBC) for low-voltage and low-power energy harvesting systems, because the output impedance of the VBC, which is derived from the analytical model, plays an important role in the VBC's performance. In our proposed method, we focus on currents flowing into input and output terminals of each stage and model the VBCs using switching frequency f, charge transfer capacitance CF, load capacitance CL, and process dependent parasitic capacitance's parameter k. A comparison between simulated and calculated results showed that our model can estimate the output impedance of the VBC accurately. Our model is useful for comparing the relative merits of different types of multi-stage SC VBCs. Moreover, we demonstrate the performance of a prototype SC VBC and energy harvesting system using the SC VBC to show the effectiveness and feasibility of our proposed design guideline.