Thermal Management of Mobile Electronics: A Case Study in Densification

摘要

The mobile electronics industry faces the ever present challenge of managing increased power dissipation density. The main driver is the increased emphasis on miniaturization, whether through volume reduction (thin laptops) or through multi-functional integration, such as mobile systems that may serve as a phone, PDA, video player/recorder, GPS receiver, etc. To design highly integrated systems, thermal management must be an integral part of the design process, from functional description to components and materials selection to form factor and usage profiles. Hence, a prior understanding of thermal performance of a mobile device based on its expected volumetric density and power density would be beneficial in determining the level of thermal enhancement required for the system.rn The goal of our research was to gain better insight into system level parameters to aid in mobile systems design. A generic case study was chosen to quantify these parameters as a function of total system power and volume. The system that was studied consisted of relatively high level computing power, an image sensor and lens system. The computing section was composed of an FPGA, 2 Gb of DDR2 DRAM and 4 Gb of Flash memory devices. The overall system size was approximately 1.5” X 2” X 0.5”. The maximum power dissipation was as high as 6 W, which required solutions beyond purely conductive thermal cooling. Extensive computational analysis was carried out using commercially available _Computational Fluid Dynamics (CFD) software to determine the system level parameters and their dependence on power levels, choice of thermal components, external environment and system volume. This study aided in establishing boundaries on system power and volume for conduction-based cooling requirements in mobile electronics. Design optimization is conducted based on the computational analysis.