Looking for 12VDC-DC ATX powersupply

[badboyscad]

hi........can anyone help me!!!. im trying to fix my PC in my car, i need a 12VDC-DC ATX powersupply which can produce +12v,-12v,+5v,-5V,+3.3v,gnd......i just need a circuit diagram and PCB design.........:|

 

[IanP]

car smps for pc

Much, much easier and cost effective, will be to get an off-the-shelf 350W 12V-240V inverter and use a standard PC SMPS with all these voltages available at required current levels ..
Regards,
IanP

 

[badboyscad]

pc smps

thanx for ur suggestion ian but does the inverter work well in automotive environment, i mean , wont the car's battery get drained soon if i use an inverter...............

 

[Johnson]

Re: car PC SMPS request

The inverter efficiency is always high, so the inverter usage is not matter, check out your PC

 

[VVV]

Re: car PC SMPS request

I don't hink you really need the -5 and -12V voltages.
For the rest, they can be easily implemented using easy to find parts, such as National's LM2576, for instance, or other parts of the SimpleSwitcher family.

Can you post the required currents? I can put together something for you.
VVV

 

[sinatra]

Re: car PC SMPS request

Hello badboyscad and all the others.

badboyscad, I share the same idea of IanP.
It is very easy to build an inverter. And once you build it, it will be available for other applications when needed (when you need to use a soldering iron in your car, or a drilling machine, etc... and there is no mains plug around...).

Also, you will not need to dismount your pc. If you put a plug in the output of your inverter, just like a wall plug, you will be able to plug your pc just like if you where at home.

You will find many examples in the internet.
Check this one in the following link:
https://www.aaroncake.net/circuits/inverter.htm

I also made a pdf file from that site if you prefere a pdf. I attach it to this message....

S.

 

[badboyscad]

Re: car PC SMPS request

thanx for considering my request, VVV and all . the currents(DC)(for ATX form factor) required are -12V,+12V,-5V,+5V,+3.3V,Gnd. the 3.3V is particularly difficult to get. i've attached a ATX pinout diagram and a reqiured amperes info.

 

[Ante]

Re: car PC SMPS request

Why make AC from DC and then back again? Why not just build a new front end for the PCs original PSU? What happens in the PSU is that the AC is rectified and chopped up again to drive the pulse transformer. Rewinding the transformer for 12V will save the unnecessary step and work much more efficient.

 

[throwaway18]

Re: car PC SMPS request

I don't think rewinding the transformer so it works on 12V DC instead of 300-400V DC is practical. You would have to redesign all the circuitry around it.

Making a 12V DC to 300V DC switcher to supply a normal PC power supply is a possibility.

 

[VVV]

Re: car PC SMPS request

It is possible to implement what you want using the following components from Linear Technology:

LTC3780 for the +12V/ 18A. This is a buck-boost so it will produce 12V even if the battery drops below 12V.

LTC1775 for each the +5V and the 3.3V supplies.

LT1076 for the -12V supply.

You then need a few other components to implement the supervisory function and generate the PWR_OK signal.

One possible problem is that the LTC3780 only works up to 36V and transients in automotive environments can be up to 60V.