Multimodal Portable Functional Brain Imaging Chip

Bum Jun Koh; Hyeon Min Bae

doi:10.23075/jicas.2022.8.4.009

Bum Jun Koh Korea Advanced Institute of Science and Technology https://orcid.org/0000-0001-8807-8221
Hyeon Min Bae Korea Advanced Institute of Science and Technology https://orcid.org/0000-0001-5513-5285

DOI: https://doi.org/10.23075/jicas.2022.8.4.009

Keywords: DLL, FDNIRS, Near-infrared spectroscopy

Abstract

Near-infrared spectroscopy is a non-invasive technology that uses source-detector pairs for measuring bio-signals such as hemodynamics. Continuous-wave near-infrared spectroscopy(CWNIRS) was widely used for signal measurement due to its simple implementation and system portability. However, this method is not suitable for absolute optical property measurement which is critical to deriving accurate tissue property. Frequency-domain NIRS(FDNIRS) and time-domain NIRS(TDNIRS) are solutions for this problem. FDNIRS operates at high speed compared with CWNIRS, which increases its hardware complexity. To solve the system bulkiness, an integrated circuit system design was implemented for FDNIRS. Fabricated FDNIRS IC used a delay-locked loop (DLL) and a low sampling rate analog-to-digital converter (ADC) to extract amplitude and phase delay information of the NIRS signal. IC system realizes a portable, real-time measurement system.

Author Biographies

Bum Jun Koh, Korea Advanced Institute of Science and Technology

Bum Jun Koh received the B.S. and M.S. degrees in electrical engineering from the Korea Advanced Institute of Science and Technology (KAIST), Dae-jeon, Korea, in 2019 and 2021, respectively. He is currently working toward a Ph.D. degree at KAIST. His research interests include near-infrared spectroscopy, analog front-end design for biomedical sensor applications, and mixed-signal design for biomedical circuit systems.

Hyeon Min Bae, Korea Advanced Institute of Science and Technology

Hyeon Min Bae received the B.S. degree in electrical engineering from Seoul National University, Seoul, Korea, in 1998 and the M.S. and Ph.D. degrees in electrical and computer engineering from the University of Illinois at Urbana-Champaign, Champaign, IL, USA, in 2001 and 2004, respectively.

From 1995 to 1996, he served his military duty in Dokdo in the East sea. From 2001 to 2007, he led the analog and mixed-signal design aspects of OC-192 MLSE based EDC ICs at Intersymbol Communications, Inc, Champaign, IL, USA. From 2007 to 2009, he was with Finisar Corporation (NASDAQ: FNSR), Sunnyvale, CA, USA, after its acquisition of Intersymbol Communications Inc.. Since 2009, he has been on the faculty of the electrical engineering at Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea, where he is currently an associate professor. In 2010, he founded Terasquare, Inc., Seoul, South Korea, a venture-funded fabless semiconductor start-up which provided low power all digital 100 Gb/s IC solutions. Teresquare, Inc. was acquired by Gigpeak (NYSE:GIG) in 2015. In 2013, He also founded OBElab, Inc., Seoul, Korea, a bio startup that manufactures portable functional brain imaging systems. His research interests span a wide range of topics in wireline communication and medical imaging systems.

Prof. Bae received the Excellence Award from the National Academy of Engineering of Korea in 2013 and the 2006 IEEE Journal of Solid-State Circuits Best Paper Award.

Homepage : https://nais.kaist.ac.kr/