Dynamic device, circuit, and system parameter variations degrade processor performance, energy efficiency, and yield across all market segments, ranging from small embedded cores in an Internet of Things (IoT) device to large multicore servers. This lecture introduces the primary variations during the processor operational lifetime, including supply voltage droops, temperature changes, transistor and interconnect aging, radiation-induced soft errors, and workload fluctuations. This presentation then describes the negative impact of these variations on processor logic and memory across a wide range of voltage and clock frequency operating conditions. To mitigate the adverse effects from dynamic variations, this lecture presents adaptive and resilient circuits while highlighting the key design trade-offs and testing implications for product deployment.
Keith A. Bowman is a Principal Engineer and Manager in the Processor Research Team at Qualcomm Technologies, Inc. in Raleigh, NC, USA. He is responsible for researching and developing circuit technologies for enhancing the performance and energy efficiency of Qualcomm processors. He pioneered the invention, design, and test of Qualcomm’s first commercially successful circuit for mitigating the adverse effects of supply voltage droops. He received the B.S. degree from North Carolina State University in 1994 and the M.S. and Ph.D. degrees from the Georgia Institute of Technology in 1995 and 2001, respectively, all in electrical engineering. From 2001 to 2013, he worked in the Technology Computer-Aided Design (CAD) Group and the Circuit Research Lab at Intel Corporation in Hillsboro, OR, USA. In 2013, he joined Qualcomm Technologies, Inc.
Dr. Bowman has published over 80 technical papers in refereed conferences and journals, authored one book chapter, received 20 patents, and presented 38 tutorials on variation-tolerant circuit designs. He received the 2016 Qualcomm Corporate Research and Development (CRD) Distinguished Contributor Award for Technical Contributions, representing CRD’s highest recognition, for the pioneering invention of the auto-calibrating adaptive clock distribution circuit, which significantly enhances processor performance, energy efficiency, and yield and is integral to the success of the Qualcomm® Snapdragon™ 820 and future processors. He is an IEEE SSCS Distinguished Lecturer. He was the Technical Program Committee (TPC) Chair and the General Conference Chair for ISQED in 2012 and 2013, respectively, and for ICICDT in 2014 and 2015, respectively. Since 2016, he has served on the ISSCC TPC.