110 VDC Input on a regular ATX PSU

**Jeeve5** · 06-14-2006, 11:47 AM

Hi

I talked to one of the guys who is working on the power supply designs that we do at the uni and he pointed me into a direction that I haven't read about before. He said that I could just input 110 VDC (* sqrt(2)) into my regular ATX PSU and it would work unless it has PFC. He said that most ATX PSUs use a bridge rectifier setup to convert AC to DC. That would be a pretty straight foward and dirty solution to get a inverter-less setup with a semi-good efficiency.

Is it really that simple or did we overlook something?

Thanks in advance!

**Jahntassa** · 06-14-2006, 12:35 PM

Just curious, but why would you want to? Also, how easy is it to upconvert 12 VDC to 110 VDC? Or heck, anything to 110 VDC?

I know you can get server and high-end hardware that'll run off 48 VDC, and some audio equipment will run off that as well, but I would have to imagine there's some pretty hefty negatives.

**didiet78** · 06-14-2006, 11:12 PM

You can conect directly 110VDC to atx psu, but conect after the bridge or pfc if exist to minimize power drop in bridge (=<3W). It's more easy to built decent dc-dc voltage converter than dc-ac (i thing).

**Jeeve5** · 06-17-2006, 05:20 PM

I have searched around a bit more and the only switching regulators that I can find go up to 100VDC Vout and therefore this option is dead

**Fusion-One** · 06-17-2006, 08:00 PM

I'd be curious to see if a transformer wound to take 14.4volts and pump it to 110v would work. I imagine it would depend on the psu, but if it was of sufficient quality it might run over a wide range of input voltages. I doubt you would be seeing anything that could survive cranking, but maybe it would regulate and run well enough with the car running (i.e. fairly stable and consistant power)

For instance, the power here in my home is very unstable and flickers often. The power will dip low enough that the flurorescent lights in my room dim, but my computer maintains it's power. (No, I don't have a UPS. :P)

**GuessWhosBack** · 06-17-2006, 08:43 PM

its going to be just as expensive to make a 12 volts - 110volt DC powersupply, as it would be to purchase a 12 volts, to 110volt AC inverter...

110volts might not even work, as normally, the PSU rectifies the AC, to get around 155volts DC, so, the 110volts may be too low...

something like this would probably run it...

http://oatleyelectronics.com/kits/k111b.html

but its not really practicle...

ALTHOUGH, it could fit in the original PSU housing, and the PSU could still be run off mains voltage

**Jeeve5** · 06-19-2006, 03:28 AM

Originally Posted by GuessWhosBack

its going to be just as expensive to make a 12 volts - 110volt DC powersupply, as it would be to purchase a 12 volts, to 110volt AC inverter...

110volts might not even work, as normally, the PSU rectifies the AC, to get around 155volts DC, so, the 110volts may be too low...

something like this would probably run it...

http://oatleyelectronics.com/kits/k111b.html

but its not really practicle...

ALTHOUGH, it could fit in the original PSU housing, and the PSU could still be run off mains voltage

Yeah, I know. That is why I said 110VDC * (sqrt(2)) in my first post

Anyways, I think I will stick with my LT3780 PSU Design that I am doing at the uni right now and ditch the 12VCD --> 150VCD --> ATX PSU idea