Journals & Conferences

Journals

• Young-Chan Lee+, Doo-Hyeon Ko+, Min-Hyeong Son, Se-Hwan Yang, and Ji-Yong Um, "Arterial distension monitoring scheme using FPGA based inference machine in ultrasound scanner circuit system," IEEE Transactions on Biomedical Circuits and Systems, vol. 18, no. 3, Jun. 2024.(https://doi.org/10.1109/TBCAS.2024.3363134)

• Min-Hyeong Son, and Ji-Yong Um, "An analog front-end amplifier with seamless discrete time-gain compensation for ultrasound scanner," IEIE J. Semicond. Technol. Scie., vol. 23, no. 6, Dec. 2023. (https://doi.org/10.5573/JSTS.2023.23.6.389)

• Young-Chan Lee, and Ji-Yong Um, "FPGA based real-time inference machine for A-mode ultrasonic echo pattern recognition," Electronics Letters, vol. 59, no. 11, Jun. 2023. (https://doi.org/10.1049/ell2.12832)

• Doo-Hyeon Ko, Young-Chan Lee, and Ji-Yong Um, "Center frequency tracking scheme to optimize pulse-echo response of ultrasonic A-mode scanner circuit system," IEEE Access, vol. 11, pp. 14524-14532, Feb. 2023. (https://doi.org/10.1109/ACCESS.2023.3244608)

• Jinhee Yoo, Donghyeon Oh, Chulhong Kim, Hyung Ham Kim, and Ji-Yong Um, "Switchable preamplifier for dual modal photoacoustic and ultrasound imaging," Biomedical Optics Express, vol. 14, no. 1, pp. 89-105, Jan. 2023. (https://doi.org/10.1364/BOE.476453)

• Ji-Yong Um, "An ultrasonic vessel-pattern imaging algorithm with low computational complexity," J. Inst. Korean Electron. Eng. vol. 26, no. 1, pp. 27-35, Mar. 2022. (https://doi.org/10.7471/ikeee.2022.26.1.27)

• Ji-Yong Um, "A compact variable gain amplifier with continuous time-gain compensation using systematic predistorted gain control," IEEE Transactions on Circuits and Systems II: Express Briefs, vol. 69, no. 2, pp. 274-278, Feb. 2022. (https://doi.org/10.1109/TCSII.2021.3090424)

• Hyun-Tae Park, and Ji-Yong Um, "Image-free ultrasound blood-flow monitoring circuit system with automatic range-gate positioning scheme: a pilot study," Applied Sciences, vol. 11, Nov. 2021. (https://doi.org/10.3390/app112210617)

• Hyun-Tae Park, and Ji-Yong Um, "A programmable pulser-receiver circuit for single transducer medical ultrasound system," IDEC Journal of Integrated Circuits and Systems, vol. 7, no. 4, Oct. 2021. (https://doi.org/10.23075/jicas.2021.7.4.007)

• Nam-Kyu Kim, and Ji-Yong Um, "An ultrasonic echo-signal based digital background calibration for pipelined SAR ADC," IEIE J. Semicond. Technol. Sci., vol. 19, no. 6, pp. 561-570, Dec. 2019.

• Ji-Yong Um, "Ultrasound transceiver beamformer and delay-control scheme for a finger vein-pattern sensor based on a 2D transducer array," IEIE Transactions on Smart Processing and Computing, vol. 7, no. 6, pp. 448 - 456, Dec. 2018.

• Ji-Yong Um, "Current-mode ultrasound beamformer with multiple-input-sequential-output memory structure," Electronics Letters, vol. 54, issue 9, pp. 545 - 546, May, 2018.

• Ji-Yong Um, "Digital calibration technique for cyclic ADC based on digital-domain averaging of A/D transfer functions," IEEK Journal of The Institute of Electronics and Information Engineers, vol. 54, no. 6, pp. 872-881, Jun. 2017. 

• Yoon-Jee Kim, Seong-Eun Cho, Ji-Yong Um, Min-Kyun Chae, Jihoon Bang, Taeho Jeon, Byungsub Kim, Jae-Yoon Sim, and Hong-June Park, “A single-chip 64-channel ultrasound RX-beamformer including analog front-end and an LUT for non-uniform ADC-sample-clock generation,” IEEE Trans. Biomed. Circuits Syst., vol. 11, no. 1, pp. 87-97, Feb. 2017.

• Ji-Yong Um, "Calibration of bandgap voltage reference using chopping technique and IIR filter," Electronics Letters, vol. 52, issue 13, pp. 1104-1106, Jun. 2016.

• Ji-Yong Um, Yoon-Jee Kim, Seong-Eun Cho, Min-Kyun Chae, Byungsub Kim, Jae-Yoon Sim, and Hong-June Park, “A single-chip 32-channel analog beamformer with 4-ns delay resolution and 768-ns maximum delay range for ultrasound medical imaging with a linear array transducer,” IEEE Trans. Biomed. Circuits Syst., vol. 9, no. 1, pp. 138-151, Feb. 2015.

• Ji-Yong Um, Yoon-Jee Kim, Seong-Eun Cho, Min-Kyun Chae, Jongkeun Song, Baehyung Kim, Seunghun Lee, Jihoon Bang, Youngil Kim, Kyungil Cho, Byungsub Kim, Jae-Yoon Sim, and Hong-June Park, “An analog-digital hybrid RX beamformer chip with non-uniform sampling for ultrasound medical imaging with 2D CMUT array,” IEEE Trans. Biomed. Circuits Syst., vol. 8, no. 6, pp. 799-809, Dec. 2014.

• Seong-Eun Cho, Ji-Yong Um, Byungsub Kim, Jae-Yoon Sim, and Hong-June Park, “A single-stage 37dB-linear digitally-controlled variable gain amplifier for ultrasound medical imaging,” IEEK J. Semicond. Technol. Sci., vol. 14, no. 5, pp. 579-587, Oct. 2014.

• Ji-Yong Um, Yoon-Jee Kim, Eun-Woo Song, Jae-Yoon Sim, and Hong-June Park, “A digital-domain calibration of split-capacitor DAC for a differential SAR ADC without additional analog circuits,” IEEE Trans. Circuits Syst. I, Reg. Papers, vol. 60, no. 11, pp. 2845-2856, Nov. 2013.

• Ji-Yong Um, Jae-Yoon Sim, and Hong-June Park, “A gate-leakage insensitive 0.7-V 233-nW ECG amplifier using non-feedback PMOS pseudo-resistors in 0.13-mm N-well CMOS,” IEEK J. Semicond. Technol. Sci., vol. 10, no. 4, pp. 309-315, Dec. 2010.

Conferences

• Young-Chan Lee, and Ji-Yong Um, "Machine learning based ultrasonic echo pattern recognition," The 30th Korean Conference on Semiconductors, Feb. 2023.

• Min-Hyeong Son, and Ji-Yong Um, "A 10-bit 50-MS/s Flash-SAR combined sub-ranging ADC," The 30th Korean Conference on Semiconductors, Feb. 2023.

• Hyun-Min Baek, Young-Chan Lee, Hyo-Jeong Choi, and Ji-Yong Um, "Ultrasonic ensemble based power estimation to extract arterial wall regions," The 30th Korean Conference on Semiconductors, Feb. 2023.

• Doo-Hyeon Ko, Young-Chan Lee, and Ji-Yong Um, "Automatic resonance frequency tracking for ultrasound system," The 30th Korean Conference on Semiconductors, Feb. 2023.

• Min-Hyeong Son, Ji-Yong Um, "Ultrasonic preamplifier with dynamic push-pull current-reuse amplifier," The 30th Korean Conference on Semiconductors, Feb. 2023.

• Min-Hyeong Son, and Ji-Yong Um, "A programmable gain amplifier with fast transient response for medical ultrasound system," The 19th International SoC Design Conference (ISOCC), Oct. 2022.

• Nam-Kyu Kim, and Ji-Yong Um, "Gradient-descent optimization based background calibration of pipelined SAR ADC using inter-stage gain adjustment," The 28th Korean Conference on Semiconductors, Jan. 2021. (Best poster award)

• Hyun-Tae Park, and Ji-Yong Um, "A sensor interface circuit for single-transducer-based ultrasound Doppler sensor module," The 28th Korean Conference on Semiconductors, Jan. 2021.

• Hyun-Tae Park, and Ji-Yong Um, "Range-Gate tracking technique for ultrasonic Doppler sensor," in IEEE Engineering in Medicine and Biology Society (EMBC), Jul. 2019. (research poster)

• Nam-Kyu Kim, Hyun-Tae Park, Ji-Yong Um, "A digital background calibration technique using ultrasonic echo signal for pipelined SAR ADC," in International Conference on Circuits/Systems, Computers and Communications (ITC-CSCC), Jun. 2019.

• Ji-Yong Um, "A review of ultrasonic beamformer ASIC," IEEE International SoC Conference (ISOCC), Nov. 2018. (invited talk)

• Nam-Kyu Kim, Sung-Phyo Choi, Ji-Yong Um, "Addition-only vein recognition algorithm for ultrasonic vein-pattern sensor," in IEEE Engineering in Medicine and Biology Society (EMBC), Jul. 2018. (research poster)

• 김남규, 최성표, 박현태, 엄지용, "Merged capacitor switching 기법과 가변 피드백 커패시터를 이용한 class-AB telescopic op amp 기반의 10비트 40MS/s pipeline SAR ADC," 대한전자공학회 하계 학술대회, 2018년 6월.

• Nam-Kyu Kim, Sung-Phyo Choi, Ji-Yong Um, "A delay-encoding scheme of ultrasonic beamformer ASIC for reduction of on-chip memory size," in IEEE International Conference on Consumer Electronics (ICCE) Asia, Jun. 2018.

• 김윤구, 김남규, 엄지용, "A class-AB telescopic operational amplifier using dynamically biased flipped voltage followers," 대한전자공학회 하계학술대회, 2017년 6월.

• Peter Ahn, Ji-Yong Um, EunJung Choi, HyunMook Park, JaSeung Gou, KwangJun Cho, KangBong Seo, and SangDong Yoo, “Power noise rejection and device noise analysis at the reference level of ramp ADC,” Proc. SPIE Image Sensors and Imaging Systems, vol. 9403, Mar. 2015.

• Ji-Yong Um, Eun-Woo Song, Yoon-Jee Kim, Seong-Eun Cho, Min-Kyun Chae, Jongkeun Song, Baehyung Kim, Seunghun Lee, Jihoon Bang, Youngil Kim, Kyungil Cho, Byungsub Kim, Jae-Yoon Sim, and Hong-June Park, “An analog-digital-hybrid single-chip RX beamformer with non-uniform sampling for 2D-CMUT ultrasound imaging to achieve wide dynamic range of delay and small chip area,” in IEEE Int. Solid-State Circuits Conf. (ISSCC) Dig. Tech. Papers, Feb. 2014.

• Seong-Eun Cho, Ji-Yong Um, Byungsub Kim, Jae-Yoon Sim, and Hong-June Park, “High slew-rate class-AB OTA,” in International Conference on Circuits/Systems, Computers and Communications (ITC-CSCC), Jun, 2013.

• Ji-Yong Um, Jae-Hwan Kim, Eun-Woo Song, Yoon-Jee Kim, Jae-Yoon Sim, and Hong-June Park, “A single-chip time-interleaved 32-channel analog beamformer for ultrasound medical imaging,” in Proc. IEEE Asian Solid-State Circuits Conf. (ASSCC), Nov. 2012.

• Jae-Seung Lee, Dong-Hee Yeo, Ji-Yong Um, Eun-Woo Song, Jae-Yoon Sim, Hong June-Park, Seong-Mo Seo, Myeong-Ho Shin, Dong-Hoon Cha, and Heesub Lee, “A 10-touch capacitive-touch sensor circuit with the time-domain input-node isolation,” in SID Symp. Dig. Tech. Papers, Jun. 2012.

• Ji-Yong Um, Jae-Hwan Kim, Jae-Yoon Sim, and Hong-June Park, “Digital-domain calibration of split-CDAC with no extra calibration DAC for a differential-type SAR ADC,” in Proc. IEEE Asian Solid-State Circuits Conf. (ASSCC), Nov. 2011.

• Jae-Hwan Kim, Ji-Yong Um, Jae-Yoon Sim, and Hong-June Park, “Time-interleaved sample clock generator for ultrasound beamformer applications,” in Proc. IEEE Int. SoC Design Conf., Nov. 2011.

• Ji-Yong Um, Jae-Yoon Sim, Hong-June Park, “A 0.7-V 233-nW analog CMOS front-end circuit for portable heart-rate monitor,” The 18th Korean Conference on Semiconductors, 2010.

• Jae-Seung Lee, Jun Hyun Bae, Ho-Young Kim, Ji-Yong Um, Jae-Yoon Sim, and Hong-June Park, “A design guide of 3-stage CMOS operational amplifier with nested Gm-C frequency compensation,” IEEK J. Semicond. Technol. Sci., vol. 7, no. 1, pp. 20-27, Mar. 2007.