Active leakage power optimization for FPGAs

We consider active leakage power dissipation in FPGAs and present a "no cost" approach for active leakage reduction. It is well-known that the leakage power consumed by a digital CMOS circuit depends strongly on the state of its inputs. Our leakage reduction technique leverages a fundamental property of basic FPGA logic elements (look-up-tables) that allows a logic signal in an FPGA design to be interchanged with its complemented form without any area or delay penalty. We apply this property to select polarities for logic signals so that FPGA hardware structures spend the majority of time in low leakage states. In an experimental study, we optimize active leakage power in circuits mapped into a state-of-the-art 90nm commercial FPGA. Results show that the proposed approach reduces active leakage by 25%, on average.