Jeongeun Song

PhD candidate

Seoul National University

Jeongeun Song received the B.S. and M.S. degrees in Dep. of Electronic Engineering from Sogang University in 2010 and 2012, respectively. In 2012, she became a member of the CIS Analog Design Team at SK Hynix Inc., working on the design of readout circuits for CMOS image sensors. She also participated in indirect time-of-flight (i-ToF) sensor development from 2019 to 2022, designing readout circuits and modulation/demodulation circuits for acquiring distance information. She is currently pursuing the Ph.D. degree at the Department of Electrical and Computer Engineering, Seoul National University. Her research interests include mixed-signal IC design, system on chip design.

A 120-mW 5-μm VGA Indirect Time-of-Flight CMOS Image Sensor with a Differential Column ADC

 

In recent years, the three-dimensional (3D) sensor market is expected to grow rapidly owing to emerging metaverse platforms and increasing expectations for AR/VR contents. Indirect time-of-flight(I-ToF) has the advantage of implementing high-resolution 3D maps at close distances of several meters; thus, it has garnered significant attention as a reasonable solution for many applications. However, as the lock-in pixel becomes smaller and the resolution develops higher, the need for low power techniques is growing. In this paper, we propose differential column A/D converter (ADC) architecture methods to reduce power consumption of column ADCs. We implemented the scheme in a 5-μm VGA i-ToF sensor with 90nm back-side illumination (BSI) technology. The 5-μm VGA sensor achieved a depth accuracy performance under 0.8% in a depth range of 0.3-3m with a sensor power of only 120mW.