Accurate prediction of transient thermal behavior of electronic systems with the use of Computational Fluid Dynamics (CFD) requires large amount of CPU time. Even though steady state response of such systems is mostly of interest, transient thermal simulations with actual time dependent power cycles should be carried out to determine the steady-state behavior. Traditionally, power dissipation values are time-averaged to obtain steady-state characteristics, which may or may not be accurate. To overcome the large associated computational cost, several different approximate models were suggested and published in the literature. Among these models, Resistor-Capacitor (R-C) thermal network approaches have been popular in obtaining the transient response for the past few decades. These approaches require rigorous curve-fitting effort followed by an optimization process and are applicable to relatively simple systems. This study presents a state-space approach to determine transient and steady state behavior of electronic systems as accurately as possible without compromising the speed. This technique is applied to a sample graphics card system and the comparisons are made with the fully transient CFD model computations. It is shown that the temperature histories obtained from the state-space approach agree very well with those from the fully transient CFD simulations, where the CPU time for the former is radically (three to four orders of magnitude) smaller compared to that of the latter.
展开▼
