Delay Optimal Low-Power Circuit Clustering for FPGAs with Dual Supply Voltages

This paper presents a delay optimal FPGA clustering algorithm targeting low power. We assume that the configurable logic blocks of the FPGA can be programmed using either a high supply voltage (high-Vdd) or a low supply voltage (low-Vdd). We carry out the clustering procedure with the guarantee that the delay of the circuit under the general delay model is optimal, and in the meantime, logic blocks on the non-critical paths can be driven by low-Vdd to save power. We explore a set of dual-Vdd combinations to find the best ratio between low-Vdd and high-Vdd to achieve the largest power reduction. Experimental results show that our clustering algorithm can achieve power savings by 20.3% on average compared to the clustering result for an FPGA with a single high-Vdd. To our knowledge, this is the first work on dual-Vdd clustering for FPGA architectures.