Dynamic voltage scaling in a FPGA-based system-on-chip

This paper presents a DVS (Dynamic Voltage Scaling) enabled SoC (System-on-Chip) processing platform based on the Leon3 open-source processor and dynamically reconfigurable clock synthesis technology available in Virtex-4 Xilinx FPGAs. A special DVS monitor unit maintains correct operation of the processor core at a given voltage by tracking the behavior of an internal delay line and stopping the processor clock through a digital clock management (DCM) macroblock when a timing error is about to occur. Upon detection of a new valid working point the DVS monitor unit reconfigures the main DCM to synthesize a new frequency-adjusted CPU clock signal and reactivates the processor. The energy savings and operation range of the technology are evaluated in the context of video coding applications by executing different motion estimation kernels.