An Energy Efficient OLED Lamp Driver for Wearable Light Therapy Device

Dong Hee Cho; Min Kyu Je

doi:10.23075/jicas.2022.8.1.002

Dong Hee Cho Korea Advanced Institute of Science and Technology (KAIST)
Min Kyu Je Korea Advanced Institute of Science and Technology (KAIST)

DOI: https://doi.org/10.23075/jicas.2022.8.1.002

Keywords: Lossless-current sensor, OLED lamp driver, Wearable light therapy device

Abstract

In this study, we propose a power conversion circuit capable of self-compensation for the organic light emitting diode (OLED) based light therapy and optical platform. In order to compensate for degradation caused by a long time operation of the OLED, a constant-current driving of the OLED should be used instead of constant-voltage driving of the OLED. To increase the efficiency of the OLED lamp driver, a single-stage structure which is combined power stage and OLED current driving stage, is suggested. Also, the SenseFET-based current sensor is used for accurate, continuous, and lossless current sensing. This study was conducted based on the TSMC 180-nm BCD process and implemented a high-efficiency OLED driving system with 2V supply voltage, an efficiency of 90.9% at 1MHz.

Author Biographies

Dong Hee Cho, Korea Advanced Institute of Science and Technology (KAIST)

Dong Hee Cho received the B.S. and M.S. degrees both in school of electrical engineering from Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea, in 2015 and 2017, respectively. He is currently pursuing the Ph.D. degree with the Korea Advanced Institute of the science and Technology (KAIST), Daejeon, Korea. His research interests inculde power management integrated circuit (IC) designs, especially inductor based DC-DC converter and low dropout(LDO) regulator.

Min Kyu Je, Korea Advanced Institute of Science and Technology (KAIST)

Min Kyu Je (S’97-M’03-SM’12) received the M.S. and Ph.D. degrees, both in Electrical Engineering and Computer Science, from Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea, in 1998 and 2003, respectively. In 2003, he joined Samsung Electronics, Giheung, Korea, as a Senior Engineer and worked on multi-mode multi-band RF transceiver SoCs for GSM / GPRS / EDGE / WCDMA standards. From 2006 to 2013, he was with Institute of Microelectronics (IME), Agency for Science, Technology and Research (A*STAR), Singapore. He worked as a Senior Research Engineer from 2006 to 2007, a Member of Technical Staff from 2008 to 2011, a Senior Scientist in 2012, and a Deputy Director in 2013. From 2011 to 2013, he led the Integrated Circuits and
Systems Laboratory at IME as a Department Head. In IME, he led various projects developing low-power 3D accelerometer ASICs for high-end medical motion sensing applications, readout ASICs for nanowire biosensor arrays detecting DNA/RNA and protein biomarkers for point-ofcare diagnostics, ultra-low-power sensor node SoCs for continuous real-time wireless health monitoring, and wireless implantable sensor ASICs for medical devices, as well as low-power radio SoCs and MEMS interface/control SoCs for consumer electronics and industrial applications. He was also a Program Director of NeuroDevices Program under A*STAR Science and Engineering Research Council (SERC) from 2011 to 2013, and an Adjunct Assistant Professor in the Department of Electrical and Computer Engineering at National University of Singapore (NUS) from 2010 to 2013. He was an Associate Professor in the Department of Information and Communication Engineering at Daegu Gyeongbuk Institute of Science and Technology (DGIST), Korea from 2014 to 2015. Since 2016, he has been an Associate Professor in the School of Electrical Engineering at Korea Advanced Institute of Science and Technology (KAIST), Korea. His main research areas are advanced IC platform development including smart sensor interface ICs and ultralow-power wireless communication ICs, as well as microsystem integration leveraging the advanced IC platform for emerging applications such as intelligent miniature biomedical devices, ubiquitous wireless sensor
nodes, and future mobile devices. He is an author of 5 book chapters, and has more than 260 peer-reviewed international conference and journal publications in the areas of sensor interface IC, wireless IC, biomedical microsystem, 3D IC, device modeling and nanoelectronics. He also has more than 40 patents issued or filed. He has served on the Technical Program Committee and Organizing Committee for various international conferences, symposiums and workshops including IEEE International Solid-State Circuits Conference (ISSCC), IEEE Asian Solid-State Circuits Conference (A-SSCC) and IEEE Symposium on VLSI Circuits (SOVC).

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