Design Methodologies and Techniques for Optimizing Power Consumption and Performance in Pipeline Circuits

Project Summary: Excessive power dissipation and resulting temperature rise have become one of the key limiting factors to processor performance and a significant component of its cost. In modern microprocessors, expensive packaging and heat removal solutions are required to achieve acceptable substrate and interconnect temperatures. Due to their high utilization, pipeline circuits of a high-performance microprocessor are major contributors to the overall power consumption of the processor, and consequently, one of the main sources of heat generation on the chip. Our research is expected to propose techniques to minimize power consumption in pipeline circuits at different design levels and, at the same time, produce guidelines and tools for optimizing their power dissipation.

A Mathematical Solution to Power Optimal Pipeline Design by Utilizing Soft Edge Flip Flops — In an ISLPED-08 paper, we presented a technique to address the problem of reducing the power consumption in a synchronous linear pipeline, based on the idea of utilizing soft-edge flip-flops (SEFF) for time borrowing and voltage scaling in the pipeline stages. We described a unified methodology for optimally selecting the supply voltage level of a linear pipeline and optimizing the transparency window of the SEFF so as to achieve the minimum power consumption subject to a total computation time constraint. We formulated the problem as a quadratic program that can be solved optimally in polynomial time. Our experimental results demonstrated that this technique is quite effective in reducing the power consumption of a pipeline circuit under a performance constraint. Next, we will improve the pipeline stages by using optimally designed flip-flops. Also, we will consider the effect of higher order constraints such as the interdependency between the setup and hold time, and then generalize the problem to the non-linear pipelines with multi-stage feed forward and feedback paths.