https://scholar.dgist.ac.kr/handle/20.500.11750/122 2026-04-04T13:19:53Z 2026-04-04T13:19:53Z Seol, Taeryoung Kim, Geunha Lee, Sehwan Kim, Samhwan Kim, Dong Wook Wie, Jeongyoon Shin, Yeon Jae Kang, Hongki Jang, Jae Eun George, Arup Kocheethra Lee, Junghyup https://scholar.dgist.ac.kr/handle/20.500.11750/57831 2025-07-25T03:28:27Z 2024-02-20T15:00:00Z

Title: A Hybrid Recording System with 10kHz-BW 630mVPP84.6dB-SNDR 173.3dB-FOMSNDRand 5kHz-BW 114dB-DR for Simultaneous ExG and Biocurrent Acquisition Author(s): Seol, Taeryoung; Kim, Geunha; Lee, Sehwan; Kim, Samhwan; Kim, Dong Wook; Wie, Jeongyoon; Shin, Yeon Jae; Kang, Hongki; Jang, Jae Eun; George, Arup Kocheethra; Lee, Junghyup Abstract: As the precise acquisition of continuous ExG (ENG, ECG, etc.) and biocurrent (chemical, PPG, etc.) signals provides further insights into chronic health conditions [1,2], a lowpower readout system capable of simultaneously recording ExG and biocurrent signals with high precision is beneficial (Fig. 33.11.1(a)). Such a system requires BW>5kHz, noise floor ~100nV/√Hz, and FOMSNDR>170dB to cover the entire ExG spectrum. Also, an input range (IR)>100mVPP is necessary to prevent saturation. Likewise, for biocurrent acquisition, a system has to meet BW>1kHz, noise floor ~1pArms/√Hz, and DR>100dB to detect small charge perturbations without saturation from large baseline currents. Extensive effort has been conducted to design a simultaneous V & I monitoring system (Fig. 33.11.1(b)). For instance, [1] allows the design of a simultaneous V & I monitoring system based on simple integration of individual readout schemes. However, this system consumes power >100μW and is unsuitable for simultaneous ExG and biocurrent signals due to the limited BW. Although [2] achieves wide BW for both signals, it cannot record V & I simultaneously due to the time-division manner and also has narrow IRs. On the other hand, [3] employing frequency division, achieves simultaneous readout while consuming low power. However, it is vulnerable to artifacts, while the BW of each V & I readout limits the other. This paper presents a simultaneous V & I recording system using a single 2nd-order continuous-time ΔΣ modulator (CT-DSM). Such simultaneous recording is achieved by using a highly linear hybrid GmC integrator with a triplet VCObased quantizer, where the differential voltage and single-ended current are combined into differential and common mode signals (Fig. 33.11.1 (c)). © 2024 IEEE.

2024-02-20T15:00:00Z Wie, Jeongyoon Jung, Sangwoo Seol, Taeryoung Kim, Geunha Lee, Sehwan Jang, Homin Kim, Samhwan Shin, Yeon Jae Jang, Jae Eun Kung, Jaeha George, Arup Kocheethra Lee, Junghyup https://scholar.dgist.ac.kr/handle/20.500.11750/57274 2025-07-25T02:42:30Z 2024-04-23T15:00:00Z

Title: A 3.3-To-11V-Supply-Range 10μW/Ch Arbitrary-Waveform-Capable Neural Stimulator with Output-Adaptive-Self-Bias and Supply-Tracking Schemes in 0.18μm Standard CMOS Author(s): Wie, Jeongyoon; Jung, Sangwoo; Seol, Taeryoung; Kim, Geunha; Lee, Sehwan; Jang, Homin; Kim, Samhwan; Shin, Yeon Jae; Jang, Jae Eun; Kung, Jaeha; George, Arup Kocheethra; Lee, Junghyup Abstract: Neurostimulation has emerged as the cornerstone that enables closed-loop brain-machine interfaces and targeted treatments for many neurological disorders. Regardless of the application, neurostimulators employ implanted electrodes to deliver charge pulses to tissues within safety limits to engender desired neural responses. However, as electrode-Tissue-impedance (ETI) varies widely (Fig. 1 (top)), neurostimulators should operate over a wide supply range to ensure both therapeutic effectiveness and safety [1]. When ETI is large, a higher supply is needed to provide adequate stimulation. However, when ETI is low, a low supply is necessary to minimize tissue damage from excessive electrical field and heat rise [1], [2]. Furthermore, power consumption during standby mode limited to under 10μ W/Ch ensures no tissue necrosis. Lastly, a stimulator capable of delivering arbitrary stimulation waveforms is also desirable for maximal efficiency and therapeutic effectiveness. © 2024 IEEE.

2024-04-23T15:00:00Z Kim, Samhwan Kim, So Yeun Choi, Seong-Kyoon Jeon, Won Bae Jang, Jae Eun Moon, Cheil https://scholar.dgist.ac.kr/handle/20.500.11750/57255 2025-07-25T03:22:33Z 2018-09-04T15:00:00Z

Title: Spheroid culture of rat olfactory receptor neurons and its application for bioelectronic nose Author(s): Kim, Samhwan; Kim, So Yeun; Choi, Seong-Kyoon; Jeon, Won Bae; Jang, Jae Eun; Moon, Cheil Abstract: A novel concept of cell-based biosensor mimicking odorants encoding process of the mammalian ORN was proposed and developed. Rat ORN precursor spheroids were formed by using recombinant protein (REP; TGPG[VGRGD(VGVPG)6]20WPC) and used as a bioelement and combined with commercialized multi electrode array (MEA). Spheroid culture of ORN precursors realized stable maintenance and long-term storage of ORN precursors with preservation of stemness characters. Physiological characters of the differentiated ORNs from spheroids were verified by monitoring change of intracellular calcium concentration upon odorant mixture stimulation and these characters were well preserved in the long-term cultured ORN spheroids. Lastly, differentiated ORN on the MEA generated electrical signals upon odorants stimulation and these signals were collected as signal patterns and analyzed for detecting and discriminating odorant types and concentrations. Developed ORN-based biosensor showed superior repeatability and reproducibility in the odorant detection and the ORN spheroid culture have potentials to be applied in the development of a bioelectronic nose and high-throughput odorant screening.

2018-09-04T15:00:00Z Kim, Sohee Jang, Hyun Woo Kwon, Hyeokjin Heo, Su Jin Pyo, Goeun Kim, Dong Su Chae, Ji Won Jang, Jae Eun https://scholar.dgist.ac.kr/handle/20.500.11750/46888 2025-07-25T02:40:21Z 2021-11-02T15:00:00Z

Title: Detection of Odorant using TFT multi-array with Various Polymers Author(s): Kim, Sohee; Jang, Hyun Woo; Kwon, Hyeokjin; Heo, Su Jin; Pyo, Goeun; Kim, Dong Su; Chae, Ji Won; Jang, Jae Eun Abstract: High selectivity of the sensor is one of the most important parameters for the electronic nose (E-nose) or gas sensor. However, many sensors have shown poor selectivity, even though some had high sensitivity. To solve this issue, we suggested a multi-sensor array concept, which consisted of thin-film transistors (TFTs) with various polymer selectors. By using TFT as a base sensor structure, sensitivity was significantly enhanced, and by adopting a polymer as the second dielectric layer, there was a remarkable improvement in selectivity. Some polymers showed unique selectivity to a specific odorant, whereas others had a moderate reaction to various odorants. Instead of common one-to-one matching between a sensor and an odorant, we used multi-output analysis using a dimensional bar chart. Eight different polymers TFTs made a specific chart pattern for four different odorants. Therefore, this sensor array and signal process concept can apply to the e-nose system, which can classify many odorants like a human simulator. © 2021 IEEE.

2021-11-02T15:00:00Z