EEMIX Lab. - Publications

Conference Papers

S. Park*, S. -H. Han, J. Kim, J. Kang, J. -H. Chun, J. Choi, S. -J. Kim*, "An Asynchronous 160× 90 Flash LiDAR Sensor with Dynamic Frame Rates of 5 to 250fps Based on Pixelwise ToF Validation via a Background-Light-Adaptive Threshold,"
IEEE International Solid-State Circuits Conference (ISSCC), Feb. 2025
W. Roh*, H. Seo, C. Piao, H. Lee, M. Kim, M. -J. Lee, S. -J. Kim, J. -H. Chun, J. Choi*, "A 400x112 CMOS LiDAR Sensor with Reconfigurable Resolution Histogramming Time-to-Digital Converters and Sub-cm Depth Refining Filter,"
IEEE Asian Solid-State Circuits Conference (A-SSCC), Nov. 2024.
J. Han*, H. Lee*, J. Cho, H. Lee, J. -H. Chun, S. -J. Kim, J. Choi*, "A Digital Dynamic Vision Sensor with SPAD pixels and Multi-Event Generation for Motion/Vibration-Adaptive Detection,"
IEEE Symposium on VLSI Circuits (VLSIC), Jun. 2024
M. Kim*, H. Seo*, S. Kim, J. -H. Chun, S. -J. Kim, J. Choi*, "A 320x240 CMOS LiDAR Sensor with 6-Transistor nMOS-Only SPAD Analog Front-End and Area-Efficient Priority Histogram Memory,"
IEEE International Solid-State Circuits Conference (ISSCC), Feb. 2024
S. -H. Han*, S. Park, J. -H. Chun, J. Choi, S. -J. Kim*, "A 160×120 Flash LiDAR Sensor with Fully Analog-Assisted In-Pixel Histogramming TDC Based on Self-Referenced SAR ADC,"
IEEE International Solid-State Circuits Conference (ISSCC), Feb. 2024
S. -H. Han, B. Kim, S. Park, Y. Park, J. -H. Chun, J. Choi, S. -J. Kim*, "A 100x80 CMOS Flash LiDAR Sensor with 0.0011mm2 In-Pixel Histogramming TDC Based on Analog Countr and Self-Calibrated Single-Slope ADC,"
IEEE Symposium on VLSI Circuits (VLSIC), Jun. 2022
J. Kang, Y. Park, J. -H. Hwang, J. -H. Chun, J. Choi, S. -J. Kim*, "A 640x480 Indirect Time-of-Flight Image Sensor With Tetra Pixel Architecture for Tap Mismatch Calibration And Motion Artifact Suppression,"
IEEE Symposium on VLSI Circuits (VLSIC), Jun. 2022
S. Park, B. Kim, J. Cho, J. -H. Chun, J. Choi, S. -J. Kim*, "An 80x60 Flash LiDAR Sensor with In-Pixel Histogramming TDC Based on Quaternary Search and Time-Gated Δ-Intensity Phase Detection for 45m Detectable Range and Background Light Cancellation,"
IEEE International Solid-State Circuits Conference (ISSCC), Feb. 2022
T. H. Nguyen, M. Imran, J. Choi, J. S. Yang, "Low-Cost and Effective Fault-Tolerance Enhancement Techniques for Emerging Memories-Based Deep Neural Networks,"
ACM/IEEE Design Automation Conference (DAC), Dec. 2021.
C. Piao*, Y. Ahn*, D. Kim, J. Park, J. Kang, M. Shin, K. Seo, S. -J. Kim, J. -H. Chun, J. Choi*, "A 70mW Indirect Time-of-Flight Image Sensor with Depth Dynamic Range Enhancement and Fixed Depth Noise Compensation,"
IEEE Asian Solid-State Circuits Conference (A-SSCC), Nov. 2021.
H. Seo*, G. Cho*, J. Kim, J. Bae, S. -J. Kim, J. -H. Chun, J. Choi*, "A CMOS LiDAR Sensor with Pre-Post Weighted-Histogramming for Sunlight Immunity Over 105 klx and SPAD-based Infinite Interference Canceling,"
IEEE Symposium on VLSI Circuits (VLSIC), Jun. 2021.
B. Kim*, S. Park, J. -H. Chun, J. Choi, S. -J. Kim*, "A 48×40 13.5mm Depth Resolution Flash LiDAR Sensor with In-Pixel Zoom Histogramming Time-to-Digital Converter,"
IEEE International Solid-State Circuits Conference (ISSCC), 2021 (Won ISSCC Silkroad Award)
J. Kim*, Y. Ko, J. Jin, J. Choi, J. -H. Chun*, "A Jitter-Tolerant Referenceless Digital-CDR for Cellular Transceivers,"
IEEE Asian Solid-State Circuits Conference (A-SSCC), Nov. 2020.
H. Seo*, H. Yoon, D. Kim, J. Kim, S. -J. Kim, J. -H. Chun, J. Choi*, "A 36-Channel SPAD-Integrated Scanning LiDAR Sensor with Multi-Event Histogramming TDC and Embedded Interference Filter,"
IEEE Symposium on VLSI Circuits (VLSIC), Jun. 2020 (Selected as a highlighted paper in VLSIC 2020).
D. Kim*, S. Lee, D. Park, C. Piao, J. Park, Y. Ahn, K. Cho, J. Shin, S. M. Song, S. –J. Kim, J. –H. Chun, J. Choi*, “A Dynamic Pseudo 4-Tap CMOS Time-of-Flight Image Sensor with Motion Artifact Suppression and Background Light Cancelling Over 120klux”,
IEEE International Solid-State Circuits Conference (ISSCC), 2020 (Won ISSCC Silkroad Award)
J. Choi*, "Review of low power image sensors for always-on imaging,"
IEEE International SoC Design Conference (ISOCC), 2016.
S. -H. Kim, H. Shin, Y. Jeong, J. -H. Lee, J. Choi, J. -H. Chun, "A 12-Gb/s Dual-Channel Transceiver for CMOS Image Sensor Systems,"
IEEE European Solid-State Circuits Conference (ESSCIRC), 2016.
J. Choi*, J. Shin, D. Kang, D.-S. Park, “A 45.5μW 15fps always-on CMOS image sensor for mobile and wearable devices,”
IEEE International Solid-State Circuits Conference (ISSCC), Feb. 2015.
B. Kang, J. Shin, J. Choi, J. D. K. Kim, “Pixel structure for asymmetry removal in ToF 3D camera,”
IS&T/SPIE Electronic Imaging, Jan. 2014.
J. Cho, S. Park, J. Choi, E. Yoon, “Area-efficient and low-power implementation of vision chips using multi-level mixed-mode processing,”
International Workshop on Cellular Nanoscale Networks and their Applications (CNNA), Jul. 2014.
J. Cho, J. Choi, S. -J. Kim, J. Shin, S. Park, J. D. K. Kim, E. Yoon, “A 5.9µm-pixel 2D/3D image sensor with background suppression over 100klx”
IEEE Symposium on VLSI Circuits (VLSIC), Jun. 2013.
S. Park, J. Choi, J. Cho, E. Yoon, “Bio-inspired multi-mode optic flow sensors for micro air vehicles”
SPIE Defense, Security, and Sensing, 2013.
J. Choi*, S. Park, J. Cho, E. Yoon, “A 3.4µW CMOS image sensor with embedded feature-extraction algorithm for motion-triggered object-of-interest imaging,”
IEEE International Solid-State Circuits Conference (ISSCC), Feb. 2013.
J. Choi*, S. Park, J. Cho, E. Yoon, “A 1.36μW adaptive CMOS image sensor with reconfigurable modes of operation from available energy/illumination for distributed wireless sensor network,”
IEEE International Solid-State Circuits Conference (ISSCC), Feb. 2012.
J. Choi*, S.-W. Han, S.-J. Kim, S.-I. Chang, E. Yoon, “A Spatial-Temporal Multi-Resolution CMOS Image Sensor with Adaptive Frame Rates for Moving Objects in the Region-of-Interest,”
IEEE International Solid-State Circuits Conference (ISSCC), Feb. 2007.
S.-W. Han, S.-J. Kim, J. Choi, C.-K. Kim, and E. Yoon, “A High Dynamic Range CMOS Image Sensor with In-Pixel Floating-Node Analog Memory for Pixel Level Integration Time Control,”
IEEE Symposium on VLSI Circuits (VLSIC), Jun. 2006.

Journal Papers

W. Roh*, H. Seo, C. Piao, M. Kim, T. Jeon, H. Lee, M. -J. Lee, S. -J. Kim, J. -H. Chun, and J. Choi*, "A High-Resolution Solid-State LiDAR Sensor with Reconfigurable Histogramming Time-to-Digital Converter and Filter for Depth Refinement,"
IEEE Journal of Solid-State Circuits (JSSC), May. 00th, 2025(accepted).
H. Lee*, J. Han, J. Cho, H. Lee, J. -H. Chun, S. -J. Kim*, and J. Choi*, "All-Digital Event-Based Vision Sensor With Multi-Event Generation for Motion/Vibration-Adaptive Detection,"
IEEE Journal of Solid-State Circuits (JSSC), Feb. 21st, 2025.
B. Kim, S. Park, S. -H. Han, J. -H. Chun, J. Choi*, and S. -J. Kim*, "A CMOS Flash LiDAR Sensor With In-Pixel Zoom Histogramming Time-to-Digital Converters,"
IEEE Journal of Solid-State Circuits (JSSC), Dec. 04th, 2024.
S. -H. Han, S. Park, J. -H. Chun, J. Choi*, and S. -J. Kim*, "A 3.1-μW Analog-Assisted Zoom Histogramming TDC in 35-μm Pixel Pitch for Flash LiDAR Sensor,"
IEEE Journal of Solid-State Circuits (JSSC), Oct. 29th, 2024.
S. -H. Han, S. Park, B. Kim, J. -H. Chun, J. Choi*, and S. -J. Kim*, "A 100 × 80 Flash LiDAR Sensor With In-Pixel Zoom-Histogramming TDC and Self-Referenced Single-Slope ADC Based on Analog Counters,"
IEEE Journal of Solid-State Circuits (JSSC), Oct. 16th, 2024.
Y. Kim, J. So, C. Hwang, W. Cheng, J. Choi, and J. Ko, "An FPGA-Based Energy-Efficient Real-Time Hand Pose Estimation System With an Integrated Image Signal Processor for Indirect 3D Time-of-Flight Sensors,"
IEEE Internet of Things Journal, Nov. 26th, 2024.
J. Kang, Y. Park, J. -H. Hwang, K. Hong, I. Son, J. -H. Chun, J. Choi, and S. -J. Kim, "An Indirect Time-of-Flight Sensor With Tetra-Pixel Architecture Calibrating Tap Mismatch in a Single Frame,"
IEEE Solid-State Circuits Letters, Nov. 2022.
H. Seo*, G. Cho, S. -J. Kim, J. -H. Chun, and J. Choi*, "Multievent Histogramming TDC With Pre-Post Weighted Histogramming Filter for CMOS LiDAR Sensors,"
IEEE Sensors Journal, Nov. 2022.
S. -H. Kim, Y. Cho, J. Lee, J. -H. Chun, and J. Choi*, "A 2.03-mW CMOS Image Sensor With an Integrated Four-Stacked Charge-Recycling Driver for Image Signal Transmission,"
IEEE Access, Sep. 2022.
S. Park, B. Kim, S. -H. Han, J. -H. Cho, J. -H. Chun, J. Choi*, and S -J. Kim*, "An 80x60 Flash LiDAR Sensor With In-Pixel Delta-Intensity Quaternary Search Histogramming TDC,"
IEEE Journal of Solid-State Circuits (JSSC), Sep. 2022.
C. Piao*, Y. Ahn, D. Kim, J. Park, J. Kang, S. -J. Kim, J. -H. Chun, and J. Choi*, "A Low-Power Indirect Time-of-Flight CMOS Image Sensor With Fixed Depth Noise Compensation and Dual-Mode Imaging for Depth Dynamic Range Enhancement,"
IEEE Transactions on Circuits and Systems I: Regular Papers, Jul. 2022.
K. -B. Nguyen, J. Choi, and J. -S. Yang*, "Checkerboard Dropout: A Structured Dropout With Checkerboard Pattern for Convolutional Neural Networks,"
IEEE Access, Jul. 2022.
J. Kim*, Y. Ko, J. Jin, J. Choi*, and J. -H. Chun*, "A Referenceless Digital CDR with a Half-Rate Jitter-Tolerant FD and a Multi-Bit Decimator,"
MDPI Electronics, Feb. 2022.
W. Park*, C. Piao*, H. Lee, and J. Choi*, "CMOS Image Sensor with Two-Step Single-Slope ADCs and a Detachable Super Capacitive DAC,"
IEEE Transactions on Circuits and Systems II: Express Briefs, Oct. 2021.
J. -H. Park*, Y. Shin, J. Choi, S. -J. Kim*, "A 5.02 nW 32-kHz Self-Reference Power Gating XO with Fast Startup Time Assisted by Negative Resistance and Initial Noise Boosters,"
IEEE Transactions on Circuits and Systems II: Express Briefs, May. 2021.
H. Seo*, H. Yoon, D. Kim, J. Kim, S. –J. Kim, J. –H. Chun, and J. Choi*, “Direct TOF Scanning LiDAR Sensor With Two-Step Multievent Histogramming TDC and Embedded Interference Filter,”
IEEE Journal of Solid-State Circuits (JSSC), Jan. 2021.
H. N. Rie*, J. Cho, J. Lee, S. Gandla, S. -J. Kim, and J. Choi*, "CMOS Skin Sensor for Mobile Skin Diagnosis using an Electronic Cotton Pad,"
IEEE Access, Sep. 2020.
D. Kim*, S. Lee, D. Park, C. Piao, J. Park, Y. Ahn, K. Cho, J. Shin, S. M. Song, S. –J. Kim, J. –H. Chun, and J. Choi*, “Indirect Time-of-Flight CMOS Image Sensor With On-Chip Background Light Cancelling and Pseudo-Four-Tap/Two-Tap Hybrid Imaging for Motion Artifact Suppression,”
IEEE Journal of Solid-State Circuits (JSSC), Sep. 2020.
J. Kim, W. Jang, Y. Lee, W. Kim, S. Oh, J. Lee, J. Choi, J. -H. Chun*, and T. B. Cho, "Design and Analysis of a 12-b Current-Steering DAC in a 14-nm FinFET Technology for 2G/3G/4G Cellular Applications,"
IEEE Transactions on Circuits and Systems-I: Regular Papers, Oct. 2019.
S. Lee, D. Park, S. Lee, J. Choi, and S. -J. Kim*, "Design of a Time-of-Flight Sensor With Standard Pinned-Photodiode Devices Toward 100-MHz Modulation Frequency,"
IEEE Access, Sep. 2019.
D. Kim* and J. Choi*, "Indirect Time-of-Flight Depth Sensor with Two-Step Comparison Scheme for Depth Frame Difference Detection,"
MDPI Sensors, Aug. 2019.
H. Seo* and J. Choi*, "Histogram-based mixed-signal time-to-digital converter array for direct time-of-flight depth sensors,"
IET Electronics Letters, Mar. 2019.
C. -J. Lee*, J. Park, C. Piao, H. -E. Seo, J. Choi*, and J. -H. CHun*, "Mutual Capacitive Sensing Touch Screen Controller for Ultrathin Display with Extended Signal Passband Using Negative Capacitance,"
MDPI Sensors, Oct. 2018.
H. Seo*, B. Kim, J. -H. Chun, S. -J. Kim and J. Choi*, "CMOS depth sensor with programmable filter circuits for environment-adaptive noise suppression,"
IET Electronics Letters, Aug. 2018.
S. -H. Kim*, H. Shin, Y. Jeong, J. -H. Lee, J. Choi*, and J. -H. Chun*, "A 12-Gb/s Stacked Dual-Channel Interface for CMOS Image Sensor Systems,"
MDPI Sensors, Aug. 2018.
K. -H. Song*, J. Choi, and J. -H. Chun*, "A Method for Enhancing the Sensing Distance of a Fingerprint Sensor,"
MDPI Sensors, Oct. 2017.
B. -Y. Um*, J. -R. Kim, S. -H. Kim, J. -H. Lee, J. Cheon, J. Choi, and J. -H. Chun*, "Design and Evaluation of a CMOS Image Sensor with Dual-CDS and Column-parallel SS-ADCs,"
Journal of Semiconductor Technology and Science, Feb. 2017.
S. -C. Kim*, S. -C. Lim, J. Shin, and J. Choi*, "Biometrics for electronic eyes: system authentication with embedded CMOS image sensor,"
IEEE Transactions on Consumer Electronics, Oct. 2016.
J. Choi* and O. Choi*, "Integrated visual sensor with 2D/3D imaging and in-situ proximity sensing for mobile devices,"
IET Electronics Letters, Aug. 2016.
J. Choi*, J. Shin, D. Kang, and D. -S. Park, “Always-On CMOS Image Sensor for Mobile and Wearable Devices,”
IEEE Journal of Solid-State Circuits (JSSC), Jan. 2016.
J. Choi*, S. Park, J. Cho, and E. Yoon*, “An Energy/Illumination-Adaptive CMOS Image Sensor With Reconfigurable Modes of Operations,”
IEEE Journal of Solid-State Circuits (JSSC), Jun. 2015.
J. Choi*, J. Shin, and B. Kang, “Global shutter-mesh architecture with surround-boosted driving scheme for time-of-flight depth sensors,"
IET Electronics Letters, Apr. 2015.
J. Choi*, J. Shin, and B. Kang, “An Architecture With Pipelined Background Suppression and In-Situ Noise Cancelling for 2D/3D CMOS Image Sensor,”
IEEE Transactions on Circuits and Systems I: Regular Papers (TCAS-I), Jan. 2015.
J. Cho*, J. Choi, S.-J. Kim, S. Park, J. Shin, J. D. K. Kim, and E. Yoon*, “A 3-D Camera With Adaptable Background Light Suppression Using Pixel-Binning and Super-Resolution,”
IEEE Journal of Solid-State Circuits (JSSC), Oct. 2014.
J. Choi*, S. Park, J. Cho, and E. Yoon*, “A 3.4uW Object-Adaptive CMOS Image Sensor With Embedded Feature Extraction Algorithm for Motion-Triggered Object-of-Interest Imaging,”
IEEE Journal of Solid-State Circuits (JSSC), Jan. 2014.
J. Choi*, S.-W. Han, S.-J. Kim, S.-I. Chang, and E. Yoon*, “A Spatial-Temporal Multiresolution CMOS Image Sensor With Adaptive Frame Rates for Tracking the Moving Objects in Region-of-Interest and Suppressing Motion Blur,”
IEEE Journal of Solid-State Circuits (JSSC), Dec. 2007.

US Patents

J. Kim, D. Park, J. Ko*, J. Choi*, "Apparatus and method of generating depth map,"
US Patent App. 17/540,927 (2022)
J. Choi*, H. Seo*, G. Cho, J. Kim, "LiDAR Device and method of measuring distance,"
US Patent App. 17/499,100 (2022)
J. Choi*, D. Kim*, "Apparatus for measuring depth with pseudo 4-tap pixel structure,"
US Patent 11,467,264 (2022)
J. Choi*, H. Seo*, J. Kim, "LiDAR Device,"
US Patent App. 17/136,620 (2021)
J. Choi*, D. Kim*, "Image sensor and image processing device including the same,"
US Patent 11,012,654 (2021)
S. -H. Kim*, J. Choi*, J. -H. Chun*, "CMOS image sensor systems using low-power multi-mode data path and methods of processing the same,"
US Patent 10,863,126 (2020)
J. Choi*, D. Park, J. Park, "Image sensor simultaneously generating image and proximity signals,"
US Patent 10,587,789 (2020)
S. Kim, J. Choi, S. C. Lim, J. A. Park, D. Park, J. S. Shin, "Certification device and method using image sensor,"
US Patent 10,038,867 (2018)
J. Choi*, E. Yoon*, "CMOS image sensors with feature extraction,"
US Patent 9,936,132. (2017)
J. Choi*, J. Park, J. S. Shin, D. Park, "Image sensing apparatus and operations using burst mode,"
US Patent 9,784,834 (2017)
J. Choi*, J. Shin, "Sensor and method for suppressing background signal,"
US Patent 9,692,996. (2017)
J. Choi*, E. Yoon*, "Image sensor with high dynamic range imaging and integrated motion detection,"
US Patent 8,619,168. (2013)
J. Choi*, E. Yoon*, "Spatial-temporal multi-resolution image sensor with adaptive frame rates for tracking movement in a region of interest,"
US Patent 8,089,522. (2012)