Apart from monitors, everything in computing tends to get smaller over time. While power supplies have remained the same size for many years, Fanless Tech has discovered this passively cooled ATX PSU from HDPlex that’s only slightly larger than an iPhone, and claims to be the world's smallest at 170 (D) x 50 (W) x 25 (H) mm.
The model in question only provides 250W, so probably isn’t one to get for a gaming rig (though you can combine two using a sync cable to make a 500W unit, one for the motherboard and the other for the GPU), but the sheer size of them makes them perfect for custom small-form-factor builds.
The PSUs are fanless and should be completely silent in use. They offer 94% efficiency and use a unibody flat transformer to eliminate noise from vibration, making it ideal for home theater PCs. The copper PCB and aluminum casing are tuned for heat dissipation, and if you get one of HDPlex’s fanless chassis, it will act as a heat sink.
The trick to the compact nature of the PSU is the use of auto-grade Gallium Nitride in the FETs for the PFC and LLC stages, allowing a high power density of 1.18W per cubic centimeter.
Gallium Nitride is a binary III/V semiconductor used as an alternative to silicon. It helps improve power density by allowing much higher sustained switching frequencies, which mean smaller working parts, and can keep working under higher temperatures. An equivalent field effect transistor made from silicon would require cooling, taking power away from the device it was trying to drive. The cost of production for GaN devices is also lower, as they are smaller and don’t require cooling fans to be built in. It’s the technology behind the ever-smaller and more powerful USB chargers that are proliferating on online stores, and other compounds of gallium, such as gallium arsenide, demonstrate significant improvements in electron mobility when used to create transistors.
The PSU will be available from June this year, and is priced at $145 with free shipping worldwide. The package contains the PSU, sync cable, and five modular power cables.
