Slashdot Mirror
Fujitsu Could Help Smartphone Chips Run Cooler
angry tapir writes: If parts of your phone are sometimes too hot to handle, Fujitsu may have the answer: a thin heat pipe that can spread heat around mobile devices, reducing extremes of temperature. Fujitsu Laboratories created a heat pipe in the form of a loop that's less than 1mm thick. The device can transfer about 20W, about five times more heat than current thin heat pipes or thermal materials, the company said.
It certainly would be; however, that's not something Fujitsu specializes in, so they're sticking to what they're good at. This will also save power, in a less than obvious way; as chips get hotter, their internal resistance increases, causing them to draw more current, causing them to get hotter still, pushing the internal resistance up higher, causing them to draw yet more current. Keeping chips cooler actually causes them to draw less power, overall. Even with cooler-running chips that barely sip power, something like this is useful to keep them cool and efficient.
APK quotes people (including myself) without context and should not be trusted. Just thought you should know.
Normally current decreases as resistance increases. Why is chip power management different?
(no snark intended. I really want to know.)
Well, I might have a way, but it only works on a semi spherical planet in a vacuum.
Because the parent got one word wrong. Typically resistance decreases as temperature increases in semiconductors, not the other way around. Metallic conductors behave in the opposite way.
Preface: I'm not qualified to discuss this in more detail than layman's terms will allow. I'm sure someone more qualified will step in and clear things up (and correct any inaccuracies in my information), and welcome them to do so.
You're thinking of resistance as a current-limiting mechanism, and you're absolutely correct in that respect. What happens, though, as the resistance of the signal path through a CPU increases, the switching current of the gates of the individual transistors in that data path also increases. This increase in switching current is greater than the current-limiting effect of the added resistance, increasing the over-all current draw of the chip.
That explanation is surely chock full of WTF-level inaccuracies, so don't quote me on that; standing by for correction.
APK quotes people (including myself) without context and should not be trusted. Just thought you should know.
Sign in and pick up some karma. I just posted an explanation that you can correct in more detail than what you posted here. Undo the damage I've done, please? :)
APK quotes people (including myself) without context and should not be trusted. Just thought you should know.
Nobody uses laptops and desktops! If you do, you're a dinosaur. Please die off already. A young hipster deserves to have your job, which you're so selfishly occupying.
"That would reduce the fans work (and their own heat!)"
Years ago, I bought a Shuttle barebones Pentium 4 with a heat pipe, hoping that it would be as quiet as the Mac Minis of the time. It was disappointing. It saved having separate CPU and PSU fans and it was a bit less noisy than the average beige box pc, but still very noticeable.
A problem with heat pipes is that they are not flexible, so the motherboard, case-mounted fan, and heat pipe must match exactly. Not so suitable for do-it-yourself pc building. And in order to reduce noise, you still need to spread the heat over a large surface, i.e. attach a lot of lamellas to the heat pipe, that you could just as well have attached directly onto the cpu cooler.
Avantslash: low-bandwidth mobile slashdot.
So I'm inclined to ask, what's the Mac Minis secret to be so silent?
It's probably explained in some video with white background and soft piano music: "I saw my friend's PC. It was okay, but it wasn't exactly quiet. I asked myself, how could that be improved. I wanted it to be whisper quiet. I knew it was okay to ask more. And that's where the story of the new cooling system of Mac Mini begins. The iCool."
In practice: some buzzy 40 mm radial fan with the text "O.E.M." silkscreened onto it, accompanied with thick layer of the most crusty thermal compound found in the market.