WP 2.0: Signoff-Quality Implementation and Validation of Energy-Efficient Clock-Less Wave Propagated Pipelining
Yehuda Kraa, Tzachi Noyb and Adam Temanc
Faculty of Engineering Bar-Ilan University Ramat Gan, Israel
ayehuda.kra@biu.ac.il
btzachi.noy@biu.ac.il
cadam.teman@biu.ac.il
ABSTRACT
The design of computational datapaths with the clockless wave-propagated pipelining (CWPP) approach is an area and energy-efficient alternative to traditional pipelined logic. Removal of the internal registers saves both area and the toggling power of these complex gates, while also simplifying the clock tree. However, this approach is rarely used in modern scaled technologies, due to the complexity of implementation and the lack of a robust, scalable, and automated design methodology that meets rigid industry standards. In this paper, we present WP 2.0, an extension of the original WP algorithm and automation utility, which demonstrated how to apply CWPP to any generic combinatorial circuit using a CMOS standard cell library. WP 2.0 advances this concept to provide full-flow implementation capabilities, providing a post-layout CWPP-ready design that meets signoff-quality industry timing requirements. The WP 2.0 utility interfaces with commercial design automation software for balancing a post-synthesis netlist to achieve a high CWPP launch rate (frequency). We demonstrate the calculation of an fused dotproduct accumulation unit, implemented with a 65nm standard cell library, providing a worst-case launch rate that is comparable to a design implemented with a 3-stage clocked pipeline with a 12% area reduction and between 37%-54% power savings. Furhtermore, the CWPP design is equipped with unique postsilicon field configuration capabilities for optimizing operation and overcoming variation.
Keywords: Wave Propagation, Clock-less Wave Pipeline, High Throughput, Low Power, Timing Constraints, STA.
