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PACIFIC: Low Power Synthesis Engine

Working with three government agencies and Princeton University for more than a decade, ASC has developed a tool to solve the low power optimization problem. As today's electronic designs become more complex and foundry technologies have shrunk, power consumption has increased, causing power management to become a critical design priority. Higher power consumption has a negative effect on battery life, packaging, cooling costs, and reliability. New low-power design methodologies are necessary to address this problem. Competition is driving the requirement for power optimization and shorter design cycles. In the past low power design methodology mainly consisted of power analysis, utilizing tools that report power consumption of a design at various stages of the design cycle. This method generally results in costly design rework (or "spins"). Today's designs require power optimization tools that address power consumption early in the design cycle and reduce time to market. As it follows from equations describing power dissipation in a circuit, there are four factors that ultimately determine power dissipation:           
                           * magnitude of supply voltage
                           * switching activity in the circuit
                           * switching capacitive loads
                           * clock frequency
Numerous optimization methods targeting each of these four factors have been explored. Reduction of supply voltage, multiple voltage supplies, reduction of capacitive loads through gate sizing, and minimization of switching activity by exploiting signal correlation are just a few. However, the four factors strongly interact in ways that may cancel out power optimization benefits obtained by adjusting only one of them. Additionally, many studies have shown that only optimizations applied sufficiently early in the design cycle, when a design's architecture is not yet fixed, have potential for radical power reduction. While gate tuning at the logic level produces reductions averaging 15%, optimizations at behavior and architectural levels can slash power consumption by close to a factor of 10. Thus, to make intelligent decisions in power optimization, the tools have to simultaneously consider all four factors affecting power dissipation, and be applied early in the design cycle.

Other factors also dictate a transition to designing at higher levels. Efficient exploration of the new delay-power-area three-dimensional space calls for new design tools with fast turnaround, and behavioral synthesis has been shown to be up to 30x faster than logic synthesis. Apart from run-time performance, designing at the behavioral level presents greater available design choices. Most importantly, the sheer complexity of today's designs forces the move to capturing designs at the behavior level, for it's hardly possible to conceptualize million-gate circuits even at the RT-level.

ASC's PACIFIC behavioral synthesis tool is used at the beginning of the design process to dramatically reduce power consumption. It allows designs to be optimized for three parameters - power, delay, and area. The tool synthesizes behavioral HDL designs into structural RTL with the primary objective of minimizing power consumption. Area of the design can be treated as either a constraint, or an optimization parameter, along with power. The tool can also determine the optimal clock period for the design. The output is compatible with standard-input RTL synthesis tools.

Obtaining a license

To obtain a license for evaluating PACIFIC and information about RTL-level library characterization, please contact ASC

Publications

K. S. Khouri, G. Lakshminarayana, and N. K. Jha, "High-level synthesis of low power control-flow intensive circuits,'' IEEE Trans. on Computer-Aided Design, vol. 18, Dec. 1999.

G. Lakshminarayana, A. Raghunathan, N. K. Jha, and S. Dey, "Power management in high-level synthesis,'' IEEE Trans. on VLSI Systems, vol. 7, Mar. 1999.

G. Lakshminarayana and N. K. Jha, "High-level synthesis of power-optimized and area-optimized circuits from hierarchical data-flow intensive behaviors,'' IEEE Trans. on Computer-Aided Design, vol. 18, Mar. 1999.

A. Raghunathan, S. Dey, and N. K. Jha, "Register transfer level power optimization with emphasis on glitch analysis and reduction,'' IEEE~Trans. on Computer-Aided Design, vol. 18, Aug. 1999.

G. Lakshminarayana and N. K. Jha, "FACT: A framework for applying throughput and power optimizing transformations to control-flow intensive behavioral descriptions,'' IEEE Trans. on Computer-Aided Design, vol. 18, Jan. 2000.

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