Timing Optimization by Gate Resizing and Critical Path Identification

Due to the rapid progress in VLSI technology, the overall complexity of the chip has increased dramatically. Both more functions and higher speed are required in modern VLSI engineering. Therefore, using a minimum amount of extra hardware to meet timing requirements is becoming a major issue in VLSI design. Here, we propose an efficient method for timing optimization using gate resizing. To control hardware overhead, a minimum (or as small as possible) number of gates are selected for resizing with the aid of a powerful benefit function. To guarantee the performance of timing optimization, a modified version of PODEM ensures that each resized gate is located on at least one critical path. Thus, resizing a gate definitely reduces circuit delay. Simulation results demonstrate that our timing optimization method can efficiently reduce circuit delay with a limited amount of gate resizing (using reasonable computing time).