A 96.8%-Efficiency Continuous Input/Output-Current Step-Up/Down Converter Powering Disposable IoTs with Reconfigurable Multi-Cell-Balanced Alkaline Batteries

Min Woo Ko, Gyeong Gu Kang, Ki Duk Kim, Ji Hun Lee, Seoktae Koh, Taehwang Kong, Sang Ho Kim, Sungyong Lee, Michael Choi, Jongshin Shin, Gyu Hyeong Cho, Hyun Sik Kim

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

4 Scopus citations

Abstract

As internet-of-things (IoT) devices continue to be installed everywhere, the concept of disposable IoT is emerging owing to better cost-efficiency and ease of maintenance without battery recharging. Lasting several years, IoTs powered with standard alkaline batteries can be a promising solution due to the long shelf life, low cost, and high reliability of these batteries as compared to the Li-ion type. As shown in the top portion of Fig. 11.8.1, a single alkaline cell has a maximum voltage of 1.5V, but it can decay down to 0.9V [1]. To power an IoT device operating with mathrm{V} {mathrm{DD}}=2mathrm{V}, a variety of design options can be considered, such as the battery configuration and the power conversion topology, as shown in Fig. 11.8.1 (bottom). The first approach is step-down conversion [2], [3] from multi-cell batteries (3×BATs) connected in series. In this configuration, cell-balancing must be carefully considered; otherwise, the energy of the BATs cannot be fully utilized if any weak cells exist among them. Considering the power conversion stage, the input RMS current mathrm{I} {mathrm{IN},mathrm{RMS}} becomes much higher than the average current mathrm{I} {mathrm{IN},mathrm{AVG}} due to the inherently discontinuous mathrm{I} {mathrm{IN}} supplied from batteries, resulting in a significant power loss in the series combination of the direct current resistance (mathrm{R} {mathrm{DCR}, mathrm{BAT}}) of batteries which in the case of 3 batteries in series is 3times mathrm{R} {mathrm{DCR}, mathrm{BAT}} (-300m Omega). Regarding step-up conversion [4], [5] with parallel-connected batteries, most of the energy imbalances are compelled to be uselessly wasted via reverse currents mathrm{I} {mathrm{B}} ' The mathrm{I} {mathrm{B}} also can cause explosion or leakage of corrosive substances. Furthermore, the inductor current mathrm{I} {mathrm{L}} is likely to be high, caused by the discontinuous mathrm{I} {mathrm{D}} delivered to the output; this significantly contributes to the power loss with a large mathrm{R} {mathrm{DCR},mathrm{IND}} of the inductor. In summary, the battery cell imbalance and the discontinuous input/output (I/O) current of converter are perhaps the major issues that prevent the full utilization of alkaline batteries in IoT applications.

Original languageEnglish
Title of host publication2020 IEEE International Solid-State Circuits Conference, ISSCC 2020
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages204-206
Number of pages3
ISBN (Electronic)9781728132044
DOIs
StatePublished - Feb 2020
Externally publishedYes
Event2020 IEEE International Solid-State Circuits Conference, ISSCC 2020 - San Francisco, United States
Duration: Feb 16 2020Feb 20 2020

Publication series

NameDigest of Technical Papers - IEEE International Solid-State Circuits Conference
Volume2020-February
ISSN (Print)0193-6530

Conference

Conference2020 IEEE International Solid-State Circuits Conference, ISSCC 2020
Country/TerritoryUnited States
CitySan Francisco
Period02/16/2002/20/20

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