Research

The VLSI Design and Automation group investigates low-power computer chips, circuits and CAD tools to aid circuit design. In addition, the group has begun researching the application of these to mobile health systems. Please see the Google Scholar site for our most recent publications.

OpenRAM

The OpenRAM project aims to provide a free, open-source memory compiler development framework for Random-Access Memories (RAMs).  It is a joint development project between University of California Santa Cruz and Oklahoma State University to enable memory and computer system research by creating an open-source compiler infrastructure.

16kbyte SRAM in AMI 0.5um 45nm 16kbyte SRAM

(Left: 16kbyte SRAM in AMI 0.5um, Right: 16kbyte SRAM in 45nm Process)

Related papers:

M. R. Guthaus, J. E. Stine, S. Ataei, B. Chen, B. Wu, M. Sarwar, "OpenRAM: An Open-Source Memory Compiler," Proceedings of the 35th International Conference on Computer-Aided Design (ICCAD), 2016
S. Ataei, J. Stine, M. Guthaus, “A 64 kb differential single-port 12T SRAM design with a bit-interleaving scheme for low-voltage operation in 32 nm SOI CMOS,” International Conference on Computer Design (ICCD), 2016, pp. 499-506.
E. Ebrahimi, M. Guthaus, J. Renau, “Timing Speculative SRAM”, IEEE In- ternational Symposium on Circuits and Systems (ISCAS), 2017

Current-Mode Clocking

In a high-performance computer system design, the clock network consumes a significant amount of power and causes the most switching noise. High power consumption requires larger batteries while switching noise degrades the accuracy of sensitive sensor measurements in modern Systems-on-Chips. Prof. Matthew Guthaus, faculty in Computer Engineering, and his graduate student Riadul Islam, now a faculty at University of Michigan Dearborn, have developed the concept of a current-mode clock distribution to address these problems. Current-mode clocking senses current flow rather than a traditional voltage swing in clock wires and thereby eliminates most of the noise and power problems in traditional clock distribution schemes. Current-mode clocking simultaneously increases the potential maximum speeds of computer chips for performance improvements. Related papers:

R. Islam, M. R. Guthaus, “Current-Mode Clock Distribution,” IEEE Inter- national Symposium on Circuits and Systems (ISCAS), 2014, pp. 1203-1206.
R. Islam, H. Fahmy, P.-Y. Lin, M. R. Guthaus, “Differential Current-Mode Clock Distribution,” Midwest Symposium on Circuits and Systems (MWSCAS), 2015, pp. 1-4.
R. Islam, M. R. Guthaus, “Low-Power Clock Distribution Using a Current- Pulsed Clocked Flip-Flop,” IEEE Transactions on Circuits and Systems I (TCAS-I), Volume 62, Issue 4, April 2015, pp. 1156-1164.
R. Islam, M. R. Guthaus, “CMCS: Current-Mode Clock Synthesis,” IEEE Transactions on VLSI (TVLSI), Volume 25, Issue 3, September 2016, pp. 1054-1062.

Resonant and Charge-Recovery Clocking

H. Fahmy, P.-Y. Lin, R. Islam, M. R. Guthaus, “Switched Capacitor Quasi- Adiabatic Clocks,” IEEE International Symposium on Circuits and Systems (ISCAS), 2015, pp. 1398-1401.
P.-Y.Lin,H.Fahmy,R.Islam,M.R.Guthaus,“LC Resonant Clock Resource Minimization using Compensation Capacitance,” IEEE International Symposium on Circuits and Systems (ISCAS), 2015, pp. 1406-1409.
B. Lacara, P.-Y. Lin, M. R. Guthaus, “Multi-Frequency Resonant Clocks,” IEEE International Symposium on Circuits and Systems (ISCAS), 2015, pp. 1402- 1405.
X. Hu, M. R. Guthaus, “Distributed LC Resonant Clock Grid Synthesis,” IEEE Transactions on Circuits and Systems I (TCAS-I), Volume 59, Number 11, November 2012, pp. 2749-2760.