Publications

Chul Kim, Jiwoong Park, Sohmyung Ha, Abraham Akinin, Rajkumar Kubendran, Patrick P. Mercier and Gert Cauwenberghs, “A 3 mm × 3 mm Fully Integrated Wireless Power Receiver and Neural Interface System-on-Chip,” IEEE Transactions on Biomedical Circuits and Systems (TBioCAS), Submitted.

Thaer Alafghani, Neeraj K. Mandloi and Sohmyung Ha, “An Adaptive-stage Rectifier for mm-scale Implants,” Electronics Letter, Submitted.

Saqib Subhan, Sachin Khapli, Yong-Ak Song and Sohmyung Ha, “A Fully Differential Potentiostat Circuit with Integrated Time-based ADCs,” Proceedings of IEEE Biomedical Circuits and Systems Conference (BioCAS), Submitted.

Rajkumar Kubendran, Jongkil Park, Ritvik Sharma, Chul Kim, Gert Cauwenberghs and Sohmyung Ha, “A 4.2-pJ/conv 10-b Asynchronous ADC with Hybrid Two-tier Level-crossing Event Coding,” Proceedings of IEEE Biomedical Circuits and Systems Conference (BioCAS), Submitted.

Mohammed F. Daqaq*, Rafael S. Crespo and Sohmyung Ha, “On the Efficacy of Charging a Battery Using a Chaotic Energy Harvester,” Nonlinear Dynamics, Submitted. *Corresponding author

Sohmyung Ha, Chul Kim, Patrick Mercier and Gert Cauwenberghs, “High-Density Integrated Electrocortical Neural Interfaces,” Elsevier (Book), In Production.

Saqib Subhan and Sohmyung Ha, “A Harmonic Error Cancellation Method for Accurate Clock-based Electrochemical Impedance Spectroscopy,” IEEE Transactions on Biomedical Circuits and Systems (TBioCAS), Accepted.

Sohmyung Ha, Chul Kim, Jiwoong Park, Gert Cauwenberghs and Patrick P. Mercier, “A Fully Integrated RF-powered Energy-replenishing Current-controlled Stimulator,” IEEE Transactions on Biomedical Circuits and Systems (TBioCAS), Vol.13, No.1, February 2019.

Saqib Subhan and Sohmyung Ha, “Harmonic Error Cancellation for Accurate Square-Wave-Based Bio-Impedance Measurements,” Proceedings of the 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), Honolulu, HI, USA, July 17-21, 2018.

Neeraj Mandloi and Sohmyung Ha, “Magnetically Balanced Power and Data Telemetry for mm-Scale Neural Implants,” Proceedings of the 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), Honolulu, HI, USA, July 17-21, 2018.

Chul Kim, Chang-Seok Chae, Young-Sub Yuk,  Chris M. Thomas, Yi-Gyeong Kim, Jong-Kee Kwon, Sohmyung Ha, Gert Cauwenberghs and Gyu-Hyeong Cho, “A 500 MHz Bandwidth 7.5 mVpp Ripple Power-Amplifier Supply Modulator for RF Polar Transmitters,” IEEE Journal of Solid-State Circuits (JSSC), Vol.53, No.6, June 2018.

Chul Kim, Sohmyung Ha, Jiwoong Park, Abraham Akinin, Patrick P. Mercier and Gert Cauwenberghs, “A 144 MHz Fully Integrated Resonant Regulating Rectifier with Hybrid Pulse Modulation for mm-sized Implants,” IEEE Journal of Solid-State Circuits (JSSC), Vol.52, No.11, November 2017.

Jiwoong Park, Chul Kim, Abraham Akinin, Sohmyung Ha, Gert Cauwenberghe and Patrick Mercier, “Wireless Powering of mm-Scale Fully-on-Chip Neural Interfaces,” Proceedings of IEEE Biomedical Circuits and Systems Conference (BioCAS), Turin, Italy, October 19-21, 2017.

Chul Kim, Sohmyung Ha, Abraham Akinin, Jiwoong Park, Rajkumar Kubendran, Hui Wang, Patrick P. Mercier and Gert Cauwenberghs, “Design of Miniaturized Wireless Power Receivers for mm-sized Implants,” Proceedings of IEEE Custom Integrated Circuits Conference (CICC), Austin, TX, USA, April 30 – May 3, 2017.

Siddharth Joshi, Chul Kim, Sohmyung Ha, Yu M. Chi and Gert Cauwenberghs, “From algorithms to devices: Enabling machine learning through ultra-low-power VLSI mixed-signal array processing,” Proceedings of IEEE Custom Integrated Circuits Conference (CICC), Austin, TX, USA, April 30 – May 3, 2017.

Siddharth Joshi, Chul Kim, Sohmyung Ha, Yu M. Chi and Gert Cauwenberghs, “2pJ/MAC 14-b 8×8 Linear Transform Mixed–Signal Spatial Filter in 65nm CMOS with 84dB Interference Suppression,” International Solid-State Circuits Conference Digest of Technical Papers (ISSCC), San Francisco, CA, USA, February 5-9, 2017.

Sohmyung Ha, Chul Kim, Abraham Akinin, Jiwoong Park, Hui Wang, Christoph Maier, Patrick P. Mercier and Gert Cauwenberghs, “Silicon Integrated High-Density Electrocortical Interfaces,” Proceedings of the IEEE, Vol.105, No.1, January 2017.

—————————————- Before 2016 —————————————-

Sohmyung Ha, Chul Kim, Jongkil Park, Siddharth Joshi and Gert Cauwenberghs, “Energy-Recycling Telemetry IC with Simultaneous 11.5-mW Power and 6.78-Mbps Backward Data Delivery over a Single 13.56-MHz Inductive Link,” IEEE Journal of Solid-State Circuits (JSSC), Vol.51, No.11, November 2016

Sohmyung Ha, Massoud L. Khraiche, Abraham Akinin, Yi Jing, Yu-Hwa Lo, William R. Freeman, Gabriel A. Silva and Gert Cauwenberghs, “Towards High-resolution Retinal Prostheses with Direct Optical Addressing and Inductive Telemetry,” Journal of Neural Engineering, Vol.13, No.5, 056003, October 2016.
– Featured in eHealthNews, AzoOptics, and Kurzweil News.

Chul Kim, Siddharth Joshi, Chris M. Thomas, Sohmyung Ha, Lawrence E. Larson and Gert Cauwenberghs, “A 1.3 mW 48 MHz 4-Channel MIMO Baseband Receiver with 65 dB Harmonic Rejection and 48.5 dB Spatial Signal Separation,” IEEE Journal of Solid-State Circuits (JSSC), Vol.51, No.4, April 2016.

Chul Kim, Jiwoong Park, Abraham Akinin, Sohmyung Ha, Rajkumar Kubendran, Hui Wang, Patrick P. Mercier and Gert Cauwenberghs, “A Fully Integrated 144 MHz Wireless-Power-Receiver-on-Chip with an Adaptive Buck-Boost Regulating Rectifier and Low-Loss H-Tree Signal Distribution,” Symposium on VLSI Circuits Digest of Technical Papers, Honolulu, HI, USA, June 13-17, 2016.

Sohmyung Ha, Abraham Akinin, Jiwoong Park, Chul Kim, Hui Wang, Christoph Maier, Gert Cauwenberghs and Patrick P. Mercier, “A 16-Channel Wireless Neural Interfacing SoC with RF-powered Energy-Replenishing Adiabatic Stimulation,” Symposium on VLSI Circuits Digest of Technical Papers, Kyoto, Japan, June 16-19, 2015.
– Selected as a Highlight Paper for Symposium on VLSI Circuits, 2015.
– Featured in IEEE Solid-State Circuits Magazine, Vol.7, No.4, pp. 93-107, Fall 2015.

Chul Kim, Sohmyung Ha, Jiwoong Park, Abraham Akinin, Patrick P. Mercier and Gert Cauwenberghs, “A 144MHz Integrated Resonant Regulating Rectifier with Hybrid Pulse Modulation,” Symposium on VLSI Circuits Digest of Technical Papers, Kyoto, Japan, June 16-19, 2015.

Chul Kim, Siddharth Joshi, Chris Thomas, Sohmyung Ha, Abraham Akinin, Lawrence Larson, Gert Cauwenberghs, “A CMOS 4-Channel MIMO Baseband Receiver with 65dB Harmonic Rejection over 48MHz and 50dB Spatial Signal Separation over 3MHz at 1.3mW,” Symposium on VLSI Circuits Digest of Technical Papers, Kyoto, Japan, June 16-19, 2015.

Jongkil Park, Sohmyung Ha, Chul Kim, Siddharth Joshi, Theodore Yu, Wei Ma and Gert Cauwenberghs, “A 12.6 mW 8.3 Mevents/s Contrast Detection 128´128 Imager with 75 dB Intra-Scene DR Asynchronous Random-Access Digital Readout,” Proceedings of IEEE Biomedical Circuits and Systems (BioCAS), Lausanne, Switzerland, October 22-24, 2014.

Jongkil Park, Sohmyung Ha, Theodore Yu, Emre Neftci and Gert Cauwenberghs, “A 65k-Neuron 73-Mevents/s 22-pJ/event Asynchronous Micro-Pipelined Integrate-and-Fire Array Transceiver,” Proceedings of IEEE Biomedical Circuits and Systems (BioCAS), Lausanne, Switzerland, October 22-24, 2014.

Chul Kim, Sohmyung Ha, Chris Thomas, Siddharth Joshi, Jongkil Park, Lawrence Larsony and Gert Cauwenberghs, “A 7.86 mW +12.5 dBm In-Band IIP3 8-to-320 MHz Capacitive Harmonic Rejection Mixer in 65nm CMOS,” Proceedings of European Solid-State Circuits Conference (ESSCIRC), Venice, Italy, September 22-26, 2014.

Sohmyung Ha, Chul Kim, Yu M. Chi, and Gert Cauwenberghs, “Low-Power Integrated Circuit Design for Wearable Biopotential Sensing,” Wearable Sensors: Fundamentals, Implementation and Applications (Edward Sazonov and Michael Neuman Ed., ISBN: 978-0-12-418662-0), Elsevier, pp. 323-352, September 2014.

Sohmyung Ha, Chul Kim, Jongkil Park, Siddharth Joshi and Gert Cauwenberghs, “Energy-Recycling Integrated 6.78-Mbps Data 6.3-mW Power Telemetry over a Single 13.56-MHz Inductive Link,” Symposium on VLSI Circuits Digest of Technical Papers, Honolulu, HI, USA, June 10-13, 2014.

Sohmyung Ha, Chul Kim, Yu M. Chi, Abraham Akinin, Christoph Maier, Akinori Ueno and Gert Cauwenberghs, “Integrated Circuit and Electrode Interfaces for Non-Invasive Physiological Monitoring,” IEEE Transaction on Biomedical Engineering (TBME), Vol.61, No.5, pp.1522-1537, May 2014.
– Highlighted as the second most frequently downloaded article in July and September 2014 and the top 20 in March, April and June 2015 in IEEE TBME Monthly.

Sohmyung Ha, Jongkil Park, Yu M. Chi, Jonathan Viventi, John Rogers and Gert Cauwenberghs, “85 dB Dynamic Range 1.2 mW 156 kS/s Biopotential Recording IC for High-Density ECoG Flexible Active Electrode Array,” Proceedings of European Solid-State Circuits Conference (ESSCIRC), Bucharest, Romania, September 16-20, 2013.

Sohmyung Ha, Massoud L. Khraiche, Gabriel A. Silva and Gert Cauwenberghs, “Direct Inductive Stimulation for Energy-Efficient Wireless Neural Interfaces,” Proceedings of the 34th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), San Diego CA, August 28-September 1, 2012.

Yeonwoo Ku, Ilku Nam, Sohmyung Ha, Kwyro Lee and SeongHwan Cho, “Close-in Phase-Noise Enhanced Voltage-Controlled Oscillator Employing Parasitic V-NPN Transistor in CMOS Process,” IEEE Transaction on Microwave Theory and Techniques (TMTT), Vol.54, No.4, pp.1363-1369, April 2006.