Title
Low-Power Design Methodology of Voltage Over-Scalable Circuit with Critical Path Isolation and Bit-Width Scaling
Abstract
This work proposes a design methodology that saves the power dissipation under voltage over-scaling (VOS) operation. The key idea of the proposed design methodology is to combine critical path isolation (CPI) and bit-width scaling (BWS) under the constraint of computational quality, e.g., Peak Signal-to-Noise Ratio (PSNR) in the image processing domain. Conventional CPI inherently cannot reduce the delay of intrinsic critical paths (CPs), which may significantly restrict the power saving effect. On the other hand, the proposed methodology tries to reduce both intrinsic and non-intrinsic CPs. Therefore, our design dramatically reduces the supply voltage and power dissipation while satisfying the quality constraint. Moreover, for reducing co-design exploration space, the proposed methodology utilizes the exclusiveness of the paths targeted by CPI and BWS, where CPI aims at reducing the minimum supply voltage of non-intrinsic CP, and BWS focuses on intrinsic CPs in arithmetic units. From this key exclusiveness, the proposed design splits the simultaneous optimization problem into three sub-problems; (1) the determination of bit-width reduction, (2) the timing optimization for non-intrinsic CPs, and (3) investigating the minimum supply voltage of the BWS and CPI-applied circuit under quality constraint, for reducing power dissipation. Thanks to the problem splitting, the proposed methodology can efficiently find quality-constrained minimum-power design. Evaluation results show that CPI and BWS are highly compatible, and they significantly enhance the efficacy of VOS. In a case study of a GPGPU processor, the proposed design saves the power dissipation by 42.79c with an image processing workload and by 51.290 with a neural network inference workload.
Year
DOI
Venue
2022
10.1587/transfun.2021VLP0002
IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES
Keywords
DocType
Volume
critical path isolation, bit-width scaling, voltage over-scaling, approximate computing
Journal
E105A
Issue
ISSN
Citations 
3
0916-8508
0
PageRank 
References 
Authors
0.34
0
6
Name
Order
Citations
PageRank
Yutaka Masuda113.10
Jun Nagayama201.69
TaiYu Cheng300.34
Tohru Ishihara402.37
Yoichi Momiyama501.69
Masanori Hashimoto646279.39