17-09-2019, 07:26 PM
Only about 20 years out of date there, Mike 
3.3V rails came in with the ATX standard in 1995 - all ATX PSUs have them. It was the previous AT standard that didn't have them.
As described, the ATX-12V standard came along with the P4 - all detailed in the link I gave. From that point on, the 12V rail became the main one.
Most have a pre-set trimmer internally, and it can be brought up a bit if needed. Resistor values can be altered if range is insufficient.
12V-only PC power supplies are where many think the industry might be heading - it certainly makes a lot of sense: 12 V only power concept
Server PSUs are often 12V only. The last one I took apart gives 62.5A - it's an amazing power density (750 watts in an absolutely tiny package).
There's an argument to go to 24V or higher, of course. Perhaps that will happen one day. Laptops are almost there with 19V.
3.3V rails came in with the ATX standard in 1995 - all ATX PSUs have them. It was the previous AT standard that didn't have them.
As described, the ATX-12V standard came along with the P4 - all detailed in the link I gave. From that point on, the 12V rail became the main one.
Most have a pre-set trimmer internally, and it can be brought up a bit if needed. Resistor values can be altered if range is insufficient.
12V-only PC power supplies are where many think the industry might be heading - it certainly makes a lot of sense: 12 V only power concept
Quote:The 12 V Only System is not an industry standard yet but a proprietary solution, which is currently implemented by all Tier 1 Systembuilders like e.g. Dell, HP, Fujitsu!
Server PSUs are often 12V only. The last one I took apart gives 62.5A - it's an amazing power density (750 watts in an absolutely tiny package).
There's an argument to go to 24V or higher, of course. Perhaps that will happen one day. Laptops are almost there with 19V.
