Voltage-island driven floorplanning considering level-shifter positions

ABSTRACT

Power optimization has become a significant issue when the CMOS technology entered the nanometer era. Multiple-Supply Voltage (MSV) is a popular and effective method for power reduction. Level shifters may cause area and Interconnect Length Overhead(ILO), and should be considered during floorplanning and post-floorplanning stages. In this paper, we propose a two phases framework VLSAF to solve voltage and level shifter assignment problem. At floorplanning phase, we use: a convex cost network flow algorithm to assign voltage; a minimum cost flow algorithm to assign level shifter. At post-floorplanning phase, a heuristic method is adopted to redistribute white spaces and calculate the positions and shapes of level shifters. Experimental results show VLSAF is effective.

REFERENCES

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INDEX TERMS

Primary Classification:
  B. Hardware
  B.7 INTEGRATED CIRCUITS
      B.7.2 Design Aids
          Subjects: Placement and routing

General Terms:
Algorithms, Design

Keywords:
convex network flow, level shifter assignment, voltage assignment, voltage-island, white space redistribution