Digitally-Assisted Auto-Calibration Techniques for Analog and Mixed-Signal Circuits Against PVT and Environmental Variations
Dr. Hsin-Liang Chen
Assistant Professor
Tamkang University, Taiwan
Abstract
This tutorial presents digitally-assisted auto-calibration techniques to mitigate process, voltage, and temperature (PVT) variations in analog and mixed-signal integrated circuits. Rather than relying on expensive multi-point post-fabrication trimming, the discussed architectures leverage on-chip sensing and digital search algorithms to implement robust self-healing mechanisms. Three silicon-proven designs demonstrate this paradigm across different circuit levels. First, a 25-μA reference current source fabricated in standard 0.18-μm CMOS employs a current-controlled ring oscillator and a 7-bit binary search controller, achieving a low temperature coefficient of 206 ppm/°C across an extreme range of −40°C to +115°C. Second, an integrator RC time-constant calibration scheme in TSMC 90-nm CMOS uses a modified 10-bit voltage-to-digital converter with a self-calibrating dynamic comparator, reducing time-constant errors from ±20% to about 1%. Third, a 6th-order Gm-C bandpass filter for capacitive touch sensing utilizes an auxiliary Gm-C LC oscillator to execute a fast 12-ms 6-bit binary search, aligning the center frequency to 200 kHz with a post-calibration frequency offset of just 2.1%. Collectively, these methodologies exhibit low-power, compact, and highly scalable solutions essential for modern resilient microelectronics.
Biography
Hsin-Liang Chen received the B.S., M.S., and Ph.D. degrees in electrical engineering from Tamkang University, Taipei, Taiwan, in 1999, 2003, and 2009, respectively. From 2010 to 2014, he worked as an Analog Circuit Design Engineer at the Industrial Technology Research Institute (ITRI), where he designed high-speed analog-to-digital converters (ADCs). From 2014 to 2016, he was a Senior Analog Circuit Design Engineer at Weida Hi-Tech, where he worked on developing touch-panel controller ICs. From 2017 to 2023, he was an Assistant Professor in the Department of Electrical Engineering at Chinese Culture University, Taipei, Taiwan. In February 2024, he joined the Department of Electrical and Computer Engineering, Tamkang University, where he is currently a faculty member. His research interests include mixed-signal CMOS integrated circuits, delta-sigma ADCs, high-speed ADCs, and low-power analog circuit design.
