Power and temperature requirements for refrigerated systems

As feature dimensions of processors shrink to 100 nanometers and smaller, leakage current becomes a significant part of total power dissipation. The magnitude of power dissipated as leakage current can approach half that of the active current at higher junction temperatures. Leakage current exhibits a strong exponential relationship with temperature. Reduction of junction temperatures from a traditional value of 85 C to a near-ambient value of 25 C can reduce leakage current to a fraction of its usual value, and total power by nearly one-third. Representative leakage current models were chosen for 100, 85 and 65 nm technologies, projected for the years 2003, 2005 and 2007. Using these models, power reduction was calculated for a range of cold plate temperatures from 15 to 25 C. This was compared to compressor power in the same range. When static leakage is 30% at 85 C, total power is lowest at the highest cold plate temperature. When static leakage is 50% at 85 C, the total power becomes nearly constant throughout the range of cold plate temperatures.