Electrical & Computer Engineering     |     Carnegie Mellon

Tuesday, May 9, 12:00-1:00 p.m. HH-1112


Puru Choudhary
Carnegie Mellon University

Hardware Based Frequency Control of Globally Asynchronous Locally Synchronous (GALS) Systems

Globally Asynchronous Locally Synchronous (GALS) systems combined with Dynamic Voltage and Frequency Scaling (DVFS) schemes can potentially reduce power consumption in modern IC designs by significant amount. We propose a hardware based technique to dynamically change the clock frequencies of a GALS system driven by dynamic workload. This technique tries to change the frequency of a synchronous island such that it will have efficient power utilization while satisfying the performance constraints. We propose a hardware design that can be used to change the frequencies of various synchronous islands that are connected together by mixed-clock FIFO interfaces. Our approach provides distributed clock control of various islands, but also enables centralized control based on system configuration.

The first part of the talk will cover the methods in which the FIFO utilization can be monitored. The reliability of these methods in representing the required frequency change will also be discussed. We will then present a hardware implementation of this method that can dynamically change the frequency of a block and achieve efficient power/energy utilization.


Puru Choudhary received his BS degree in Instrumentation Engineering from Indian Institute of Technology, Kharagpur, India. He worked as a R&D Engineer in Synopsys and as an IC Design Engineer in Agere Systems. He has participated in the design of three modem ICs which are now in production. Currently, he is a PhD candidate at Carnegie Mellon University in Department of Electrical and Computer Engineering and is advised by Prof. Diana Marculescu. His primary research interests include low power design and design of GALS systems.