Patent ID: 8281275

Claim:
A method of reducing leakage power for a cell based circuit design that includes cell instances forming signal paths through the circuit design, the method comprising: determining slack values for the signal paths of the circuit design, the slack values indicating that a plurality of the signal paths have positive slack; converting the positive slack for the plurality of the signal paths to negative slack by, for each of a plurality of the cell instances of the circuit design, replacing the cell instance with a pivot variant associated with the cell instance, the pivot variant identified from a set of footprint equivalent variants of the cell instance and corresponding to a maxima of a delay-leakage function of the set of footprint equivalent variants; converting, by a computer, the negative slack for the plurality of signal paths back to positive slack by iteratively performing the following steps until a terminating condition is reached: selecting a signal path of the plurality of signal paths having negative slack; determining replacement values for variants of a plurality of the cell instances in the selected path; and replacing one or more of the cell instances in the selected path based on the replacement values; and outputting a revised circuit design resulting from converting the negative slack back to positive slack.