Slashdot Mirror
Startup Offers Peltier-On-Chip
LowSNR writes "The South Carolina based startup Nextreme, Inc. is developing technology to put Peltier Coolers in chip packages, according to an Ars Technica report. The tiny coolers could be situated on top of local hotspots on the die and pump heat away through a package pin to the motherboard. Also, the Seebeck Effect allows the waste heat to be used to be harvested to generate/reclaim power."
Peltier devices on-chip have been used for a while, whenever temperature variations are intolerable. Some examples: Analog Devices AD595 thermocouple amp, which uses in-chip thermal calibration to ensure a cold junction of known temperature, and many voltage regulators and switching supply controllers that use temperature-controlled bandgaps as their voltage reference.
Nostalgia's not what it used to be.
The PCB is often used as a heatsink for SMD chips. It wouldn't work too well for a CPU, unless we adopt a new form factor with a surface area of 5,490 cm^2, or roughly a 2.5' square (and it would need a lot of heatpipes to make up for the extra distance between the CPU and the edges of the heatsink).
I once thought of tossing one of these thermoelectric (TEC) coolers in my system to try and help with waste heat, but the trouble with the seebeck effect is that it reaches a cutoff point fairly quickly. You see, the "cool" side of the tec doesn't remain cool, it heats up as well meaning that the temperature difference grows gradually smaller and smaller, which in turn reduces output of voltage and becomes a vicious cycle, building up more and more heat on the hot side.
TEC's are great when using the peltier effect since the electric side can be managed easily, so long as there is a way to pump away the waste heat. But the seebeck effect is not a solution to waste heat, not unless there is a breakthrough in efficiency i'm not aware of.
Um, this isn't anything special. All a peltier is is a bloody heat pump. In this case they figured out how to selectively locate where the TEC is applied. Back in the day (mid to late 90's) they used to attach a refrigerator to the chip. I thought it was a rather novel idea until I discovered that people playing with medical equipment and/or lasers were using TECs to pump off excessive heat from their devices. I tipped off the folks over at Tom's Hardware and a few months later people playing with these things on their PCs. It was kind of neat how people were able to drop their CPU cores below 0 deg and overclock to mass effect. The problem was and still is that these buggers are lousy when it comes to efficiency. For only a 20deg C differential they nabbed as much power as the bloody CPU they're attached to. So for your 60 watt CPU you end up having to stuff a heatsink (or equivalent) on it sized for 120 watts. While these guys appear to have figured out how to shrink the discrete unit size their documentation suggest they're just as power hungry. The energy recovery when in passive mode doesn't even come close to compensating for their power consumption when actively cooling let alone reclaiming enough waste heat to compensate for the energy consumed by the processor (or whatever they're attached to) itself.
Two of my imaginary friends reproduced once