□ A research team led by Professor Junghyup Lee from the Department of Electrical Engineering and Computer Science at DGIST (President Kunwoo Lee) has developed a core technology for an “ultra-low-power, high-resolution analog-to-digital converter (ADC)” to stably measuring biosignals (ExG), such as electrocardiograms (ECG) and electroencephalograms (EEG), even in wearable environments involving vigorous motion. The team implemented this technology in an actual chip and successfully completed functional validation.
□ Biosignal measurement using wearable devices such as smartwatches requires minimizing noise, as the signals are extremely weak. In particular, “motion-induced interference” caused by changes in skin–electrode contact during user movement is the primary cause of signal distortion. To address this, the measurement circuitry must simultaneously achieve low noise and a wide input range, while maintaining extremely low power consumption. However, these requirements are inherently conflicting in circuit design, making them a longstanding and difficult challenge to achieve simultaneously.
□ To address this challenge, Professor Junghyup Lee’s team proposed a “noise-shaping SAR ADC” architecture that suppresses sampling thermal noise (random signal interference caused by external factors such as temperature) by pushing it into the high-frequency domain. Using this proprietary architecture, the team achieved world-class low-noise performance that remains robust against variations in process, voltage, and temperature without relying on complex calibration schemes or large capacitors (charge storage elements).
□ This achievement is significant in that it presents a core design methodology capable of simultaneously realizing low noise, wide input range, and ultra-low power consumption—all essential requirements for wearable devices—within a single semiconductor chip (a unified architecture). The technology is expected to be applied broadly, including not only long-term health monitoring in daily life, but also high-precision medical devices, by minimizing signal distortion even in environments with severe external interference.
□ “We have proposed an innovative ADC architecture that satisfies the key requirements for biosignal measurement even under large, unavoidable motion conditions in wearable environments,” stated DGIST Professor Junghyup Lee. Postdoctoral researcher Geunha Kim added, “This study is expected to make a significant contribution to advancing next-generation wearable and medical device technologies for long-term biosignal monitoring.”
□ The study was funded as part of the Basic Research Program (Basic Research Laboratory) and the Bio & Medical Technology Development Program (Leading Convergence Technology Development for Neuroscience) by the Ministry of Science and ICT and the National Research Foundation of Korea; the International Cooperative Development Program for Fundamental Technologies (Korea-EU Semiconductor R&D Cooperation); and the AI Star Fellowship Program of the Institute for Information communication Technology Planning and Evaluation (IITP). The research findings were presented at the International Solid-State Circuits Conference (ISSCC), the world’s most prestigious conference in semiconductors also known as the “Chip Olympics.” Furthermore, Professor Junghyup Lee’s team has published a total of five papers as first authors in the biomedical sessions of ISSCC over the past five years, establishing itself as the leading research group worldwide in terms of publication output in this field.
