An Efficient Chip-level Time Slack Allocation Algorithm for Dual-Vdd FPGA Power Reduction

To reduce FPGA power, a linear programming (LP) based time slack allocation algorithm, EdTLC-LP, has been proposed recently for Vdd-programmable interconnects without using Vdd-level converters for mixed wire lengths. However, it takes a long time to solve the LP problem for time slack allocation. In this paper, we develop EdTLC-NW, a slack allocation algorithm based on min-cost network flow to reduce runtime. Compared to single Vdd FPGA with power-gating, EdTLC-LP and EdTLC-NW reduce interconnect power by 52.71% and 52.52%, respectively. EdTLC-NW achieves as good results as EdTLC-LP but runs 8× faster on average. Furthermore, the speedup increases for larger circuits and EdTLC-NW is 20× faster for the largest circuit.