Low Power Applications and Technologies

Graphite heat spreaders are widely used in smartphones, tablets, laptop PC and many other applications. It is time to replace graphite heat spreaders with thermal ground planes (TGPs). As shown in the figure, TGP's effective thermal conductivities are signififacantly higher than the best graphite heat spreader thicker than 0.1mm. In addition to thermal conductivity, two other design factors should be considered: thickness and length of the heat spreader. The temperature difference as shown would be much larger if the graphite spreader's thickness is reduced to only 0.3mm or 0.15mm.  The difference in thermal performance would be substantially larger if the spreader is longer than 115mm.

TGP is going to replace the graphite heat spreader with the following features: a) excellent thermal performance with Keff = 4,000 to 25,000 W/mK; b) lower cost (the thick, high-K graphite studied is expensive); c) light (yes, TGP can be lighter in some cases); d) foldable; and e) RF transparent.In addition, TGP can be applied to high heat flux and/or high power applications, which cannot be served by a graphite heat spreader due to its high thermal resistance along the vertical, out-of-plane direction.

Note: It should be noted that TGP outperforms graphite even with a much thinner configuration. When the spreader is longer than 115mm, the difference in performance will become larger..

Polymer TGP