Neuromorphic system using capacitor synapses

Abstract Artificial intelligences are indispensable social infrastructures, neural networks are embodiment methodologies, and neuromorphic systems are promising solutions for compact size and low energy. Memristors were first prepared for the synapse devices but incur energy consumption, and memcapa...

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Main Authors: Reon Oshio, Takumi Kuwahara, Takeru Aoki, Mutsumi Kimura, Yasuhiko Nakashima
Format: Article
Language:English
Published: Nature Portfolio 2025-01-01
Series:Scientific Reports
Online Access:https://doi.org/10.1038/s41598-025-87924-6
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author Reon Oshio
Takumi Kuwahara
Takeru Aoki
Mutsumi Kimura
Yasuhiko Nakashima
author_facet Reon Oshio
Takumi Kuwahara
Takeru Aoki
Mutsumi Kimura
Yasuhiko Nakashima
author_sort Reon Oshio
collection DOAJ
description Abstract Artificial intelligences are indispensable social infrastructures, neural networks are embodiment methodologies, and neuromorphic systems are promising solutions for compact size and low energy. Memristors were first prepared for the synapse devices but incur energy consumption, and memcapacitors were next prepared but have small dynamic ranges of capacitance. In this research, we have developed a neuromorphic system using capacitor synapses. Here, multiple capacitors have binary-weighted capacitances and are controlled to be connected to intermediate signals. They are discharged through transistors, and when they fall below the threshold voltage, the output signals are inverted. After all, electric charges in the multiple capacitances are summed and measured by the inverting intervals, which is the same as multiply–accumulate operation. A large-scale integration chip is actually fabricated. The working is confirmed by MNIST, and the circuit-aware rounding improves the accuracy to 96%, indicating a sufficient possibility for practical applications, and the energy efficiency is 163 GOPS/W even by the 180 nm technology, indicating a great potential for low energy consumption.
format Article
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institution Kabale University
issn 2045-2322
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publishDate 2025-01-01
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series Scientific Reports
spelling doaj-art-4395fe0af41941cfa92cf668f70a51e52025-02-02T12:24:38ZengNature PortfolioScientific Reports2045-23222025-01-011511910.1038/s41598-025-87924-6Neuromorphic system using capacitor synapsesReon Oshio0Takumi Kuwahara1Takeru Aoki2Mutsumi Kimura3Yasuhiko Nakashima4Nara Institute of Science and Technology (NAIST)Nara Institute of Science and Technology (NAIST)Ryukoku UniversityNara Institute of Science and Technology (NAIST)Nara Institute of Science and Technology (NAIST)Abstract Artificial intelligences are indispensable social infrastructures, neural networks are embodiment methodologies, and neuromorphic systems are promising solutions for compact size and low energy. Memristors were first prepared for the synapse devices but incur energy consumption, and memcapacitors were next prepared but have small dynamic ranges of capacitance. In this research, we have developed a neuromorphic system using capacitor synapses. Here, multiple capacitors have binary-weighted capacitances and are controlled to be connected to intermediate signals. They are discharged through transistors, and when they fall below the threshold voltage, the output signals are inverted. After all, electric charges in the multiple capacitances are summed and measured by the inverting intervals, which is the same as multiply–accumulate operation. A large-scale integration chip is actually fabricated. The working is confirmed by MNIST, and the circuit-aware rounding improves the accuracy to 96%, indicating a sufficient possibility for practical applications, and the energy efficiency is 163 GOPS/W even by the 180 nm technology, indicating a great potential for low energy consumption.https://doi.org/10.1038/s41598-025-87924-6
spellingShingle Reon Oshio
Takumi Kuwahara
Takeru Aoki
Mutsumi Kimura
Yasuhiko Nakashima
Neuromorphic system using capacitor synapses
Scientific Reports
title Neuromorphic system using capacitor synapses
title_full Neuromorphic system using capacitor synapses
title_fullStr Neuromorphic system using capacitor synapses
title_full_unstemmed Neuromorphic system using capacitor synapses
title_short Neuromorphic system using capacitor synapses
title_sort neuromorphic system using capacitor synapses
url https://doi.org/10.1038/s41598-025-87924-6
work_keys_str_mv AT reonoshio neuromorphicsystemusingcapacitorsynapses
AT takumikuwahara neuromorphicsystemusingcapacitorsynapses
AT takeruaoki neuromorphicsystemusingcapacitorsynapses
AT mutsumikimura neuromorphicsystemusingcapacitorsynapses
AT yasuhikonakashima neuromorphicsystemusingcapacitorsynapses