Development of effective thermal characterization on handheld devices by matrix method

The thermal coupling effect between multiple chips cannot be ignored in handheld devices as they were not only all inside a compact system but also consumed comparable power simultaneously in practical scenarios. To shorten the time needed for thermal analysis, besides thermal simulation, an efficient analysis method by matrix method based on the concept of thermal network was developed in this study. It involves two matrixes as one was for the prediction of chipsets junction temperature to eliminate reliability or performance issue for electronics components, and the other was used for device skin temperature. In order to validate this proposal, in the first part, the thermal model of a handheld device was validated through a series of package and mock-up phone thermal experiments. The experiment includes not only one heat source in the standard JEDEC package level test but multiple heat sources on the phone level. Compared with experimental data, a range of +/-6.5% and +/-9% error was achieved for package and system level thermal model respectively. In the second part, two matrixes of thermal characteristic resistance derived from a simulate solution space were proven to be applicable in the concerned temperature-rising range of consumer electronics devices. It´s indicated by the experimental data that the two matrixes method can serve as an effective thermal characterization tool with +/-4% and +/-2% average error on all chips junction temperature and device skin temperature in all scenarios respectively. With the proposed 2-matrix-based method, the analysis time can be significantly reduced and the benefits of various thermal designs were discussed to deliver some thermal management guidelines from the thermal network´s point of view.