Power integration

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Sponsored by 37 While the device is protected from entering a thermal runaway state, the device can become warm to the user if they are talk- ing on it, holding it, or even have it close to them in their clothing. On the morning of the test, I upgraded Android on my Samsung Galaxy S5. Dur- ing the upgrade, the S5 became warm to the touch, but cooled quickly once the upgrade was complete. This demonstrates the challenges smartphone OEMs have in designing and programming for situations that may even be beyond their control. And in all of the test cases, none of the phones reached a point of overheating past the OEM or silicon vendor recom- mendations, or to a point that would make using any of them uncomfortable. Benchmarking drawbacks While these tests did not simulate the exact situation, which was to put a system benchmark into a loop to run it over and over again, that caused the HTC One M9 or LG G Flex 2 to overheat during the ini- tial benchmark tests of the devices, none of the devices came close to overheating during these tests. This begs the question: Why did those devices overheat during the initial benchmarking? The answer could lie in the newness of the devices or the benchmarking process itself. On one hand, OEMs often provide pre- production units to reviewers before they are completely qualified for release. As a result, not all the software and settings may have been fully tested for potential issues. On the other hand, benchmark- ing is about achieving the best scores. Maybe, the OEMs disabled some of the thermal protection features by adjusting the thermal settings to a higher level or by adjusting other system operating set- tings to higher levels to achieve a higher benchmark score. Logic would tend to lead toward the latter reasoning, but with- out any official claim from the OEMs, any or all of those conditions may have led to the resulting situation. However, there are no reports of higher than normal return rates on any of the smartphones using the Snapdragon 810 chipset. Takeaways Just as PC vendors faced a thermal bar- rier when using the dreaded Intel Pentium 4 processor over a decade ago, smart- phone OEMs face similar challenges with smartphone designs today and the SoC is just one factor to consider. While the two silicon solutions are drastically different in operation, the smartphone SoCs are much more complex with over 30x the number of transistors in roughly a 15% smaller die on average. Unfortunately, other mobile and small form factor solutions face similar design challenges going forward, especially as performance requirements increase, package requirements shrink, and the pow- er-saving benefits of Moore's Law wane.p —Jim McGregor is the principal analyst for Tirias Research.

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