Re:Ultra compact GAN ATX power supply delivers up to 250 Watts
by Doxin on Monday May 30, 2022 @02:56AM
(#31556170)
On the other hand GaN is much more tolerant of hight temperatures than regular resistors, so who knows which way the balance would fall?
Of course GaN is a much newer technology too so I imagine it'd have some serious catching up to do before it gets to the scales where it'd be useful for CPUs.
As a quick rule of thumb for huge transistor count ICs: Power (heat) = freq*Voltage^2
I won't go into detail, but you can see how for a CPU designer decreasing voltage is critical to increasing speed. Remember a decade ago when CPUs were like 1.2V and we hit this ~3GHz "wall"? But now due to breakthroughs in process nodes, CPUs are running I think ~0.8V but boosting up to 5GHz.
If we make the same CPU on a GaN process, the transistors would probably need ~3V to switch, and thus need to be run about 9x slower to meet the same package power (or I guess you could run it at the same speed but then try and figure out how to cool a 9x higher TDP CPU).
Furthermore, GaN is difficult to manufacture into a monocrystaline perfect lattice compared to Silicon. You can image that for modern 7nm/5nm nodes, where there are sometimes angstroms of distance in a transistor, having a foundation full of defects can be devastating to the yield.
Power electronics is a totally different domain with different challenges. In this area GaN excels, but for ICs I don't think it makes sense. Let's see in 20 years though. GaN is relatively new compared to Silicon and might just need some further refinement.
Just my 2c though. Someone correct me if I'm wrong.