Accurate Thermal-Profile Estimation and Validation for FPGA-Mapped Circuits

Accurate thermal profile estimation for FPGA, at design time, is necessary to avoid unexpected thermal hot-spots in the circuit before deploying the FPGA to the in-field operation. Both accurate dynamic and leakage power values are needed for the thermal profile estimation and they can be estimated using the FPGA vendor´s tools. However these report leakage power as a single value for the whole chip, and no details are given in literature or the FPGA toolset about its distribution across the FPGA chip for the thermal simulation. To cope with this problem, we present a method for properly distributing the leakage power across the FPGA chip. The method uses a temperature-leakage loop estimation model for distributing and adapting the leakage power for more accurate thermal simulation. Furthermore, to accurately calibrate the presented method and its model and also to validate the resulting thermal profiles, we utilize an infrared thermal camera, which measures the emissions from the backside of a Virtex-5 FPGA chip. The results of testing several designs, with different sizes and frequencies, show that our approach can achieve accurate thermal-profile estimation when compared to the camera measurements, with average absolute estimation error of around 1°C across the chip.