A linear algorithm for full-chip statistical leakage power analysis considering weak spatial correlation

Full-chip statistical leakage power analysis typically requires quadratic time complexity in the presence of spatial correlation. When spatial correlation are strong (with large spatial correlation length), efficient linear time complexity analysis can be attained as the number of variational variables can be significantly reduced. However this is not the case for circuits where gate leakage currents are weakly correlated. In this paper, we present a linear time algorithm for statistical leakage power analysis in the presence of weak spatial correlation. The new algorithm exploits the fact that gate leakage current can be efficiently computed locally when correlation is weak. We adopt a newly proposed spatial correlation model where a new set of location-dependent uncorrelated variables are defined over virtual grids to represent the original physical random variables via fitting. To compute the leakage current of a gate on the new set of variables, the new method uses the orthogonal polynomials based collocation method, which can be applied to any gate leakage models. The total leakage currents are then computed by simply summing up the resulting orthogonal polynomials (their coefficients) on the new set of variables for all gates. Experimental results show that the proposed method is about two orders of magnitude faster than the recently proposed grid-based method [3] with similar accuracy and many orders of magnitude times over the Monte Carlo method.