Measure twice and cut once: Robust dynamic voltage scaling for FPGAs

Although dynamic voltage scaling (DVS) is a popular power reduction solution that has been widely used by processors and ASICs, it is still not commercially adopted by FPGAs. A unique feature of FPGAs that leads to challenges in adopting DVS is that the critical path and hence the minimum safe V _dd depends on the configured application. We present a robust DVS technique that solves these challenges. For each application, we generate a calibration table (CT) that stores the actual failing points of that application on a specific FPGA, under various operating conditions. This CT is used to scale V _dd while the application is running to guarantee safe operation with minimal power consumption. We develop an automated tool (FRoC) that ensures a Fast-Robust-Calibration of the FPGA to any application using it. FRoC ensures that the calibration process is invisible to FPGA users and does not add any extra manual steps to the design process. We show that our proposed DVS technique achieves a 33% total power reduction on two large applications.