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I am working on a project which requires me to use a battery to run a computer. I planned to work with a 24V battery connected to a DC input (24V,1000W) ATX power supply and connect it to the PC. But now that the ATX power supply is very bulky and more concerning is its efficiency (around just 75%). Since buck has very good efficiency i can do some work around and get the voltages 12V, 5V & 3.3V. But i am not sure how to design on the power good and power ON signals(For instance i know both signals operate at 5V but not more than that). As for the protection circuit, we can have a fuse installed or i can install a circuit breaker in the buck converter.

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    \$\begingroup\$ I'd think very carefully about doing that. Those power supplies are so bulky because they work through a number of scenarios you may not think of. You may have to provide multiple rails of the same voltage (like multiple 5V rails) fed from different converters so that the device can get required amperage. You may have to output very specific ripple rejection, etc. By the time you are done, you'll end up with a big bulky supply just like the one you want to avoid, and probably a worse efficiency. \$\endgroup\$ – Ron Beyer Mar 12 '20 at 20:09
  • \$\begingroup\$ it's much easier to use 24v UPS \$\endgroup\$ – Peter MP Mar 12 '20 at 20:21
  • \$\begingroup\$ Thank you for your opinion. But, Can i just use a buck converter(from battery) to produce each voltage so that i can avoid the things that you mentioned? also, my question is how to generate the clocking signals of power good and power ok. \$\endgroup\$ – SKR Mar 13 '20 at 12:26
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You're on the right track. Take the next step and consider using a 48V source, following emerging practice in data center technology.

More here: https://blog.se.com/datacenter/2018/05/24/12v-vs-48v-the-rack-power-architecture-efficiency-calculator-illustrates-energy-savings-of-ocp-style-psus/

48V ATX power units are available from various sources in the same form factors as for standard IT gear.

Going even smaller, this one in particular is a module that plugs directly onto the motherboard ATX header, accepts 6-32V: https://www.mini-box.com/DC-DC

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  • \$\begingroup\$ Hi, Thanks for your answer, yes i did check the mini dc-dc converters. but i am looking to support a gaming PC that consumes more than 500W for which the mini DC-DC wouldn't work. \$\endgroup\$ – SKR Mar 13 '20 at 12:24
  • \$\begingroup\$ Yes, those are made for mini-ITX type platforms. That said, 1000W is a big supply. The smallest type may be a server unit for 1U or more likely 2U form factor. They will be noisy however, much more so than the bulky standard ATX type which has room for a bigger fan. \$\endgroup\$ – hacktastical Mar 13 '20 at 15:51

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