PC Power supply

[MaXiZ]

Hi to all.
I've tryed to search here and on the web.
Did exist e schematic for this?
Car battery (12v) =>PC Power supply (+/-12V,+/-5V,+3,3V)??
I need to run a k6-233, 40Gb HD, Ati rage Pro PCI so i don't need so much power i think...

 

[wes-ninja250]

Cheapest way to do this is with a commercial inverter, plugged into the regular AC power supply. They have really come down in price over the last few years.

If you need smaller, well, that's trickier. 🙂

Wes

 

[MaXiZ]

Ok just bought a power inverter (12V DC=>230V AC) of 400W.
On techincal data they say "Modified sine wave.
Now that's what happen..
Plug a lamp and it turn on! 🙂
Plug a PC and it doesen't turn on! 🙁
Why?
Any suggest or idea?
Thanx in advance

 

[tade]

I only know a bit about this. The RMS voltage output of your device will be 230v, however the frequency and the amplitute of that sin wave will probably not be the same as your residential power. That said, inverters work perfectly for resistive loads like lamps and heaters, but could have trouble with systems which require that certain sin function.

 

[MaXiZ]

So i've to buy another inverter?

 

[Tweeker]

Why not switching regulators? Lots in these voltages available. Might be rather technical to implement though.

If we dont care about efficiency at all (ei, run off the alternator), you could use linear regulators.

 

[MaXiZ]

Could u explan a little better?
I'm not an expert..
What should i do exactly?

 

[Tweeker]

Switching power is beyond my ken in the minute details really, that was just a suggestion. This is the ultimate solution, but may be more challenging and/or expensive than other approaches.

A linear regulator is essentially just burning away the difference between voltage in and desired output. Glass smooth DC in exchange for heat.

LM338 datasheet has some examples.

 

[Tweeker]

Youve already got the inverter I see, for whatever reason your PC power supply is unhappy with it, lamps are alot more forgiving. Check that everything has the correct settings and connections.

Just to make sure, this pc works fine on the ac mains?

 

[mflorin]

In my opinion, inverter doesn't like the input capacitors of the pc power supply. I think that at the first moment, they look like a short circuit for the inverter's output and probably a current protection acts.

Connect a resistor between the inverter's output and pc power supply and try again. If it works you can bypass then the resistor with a relay or a triac.

Regards,
Florin

 

[Sangram]

You could probably use linear regulators since you have a 12V input.

Remember that in PC systems that old, the CPU etc. drew power from 3.3 V rails. So you have to have a very robust regulator/series pass on that rail, at least 15 amps current draw.

Check out www.mp3car.com they have links to some nice 90 watt SMPS supplies for car PC. May suit yyour requirement, some of them are so small they'll plug into the ATX connector directly!!

 

[tom_73]

hi,

there are great differences in that converters output sine wave, look into eBay descriptions (for example) and dont buy the cheapest, better the most expensive 😉.
Be sure that you get much overhead, for example your PC (in this case) take about 70-80 watts input, get an inverter with 600 watts.
Also try a very good Power Supply like heavy-weight/great quality Fortron Source (FSP).

As you dont need so big PSU you can also look for FSP 145 (i.E. 145-50 NI on eBay), these are Mini or Micro ATX PSUs with short cables and different mounting, but save space. I drove an Athlon Barton 2400 XP + GF2 GTS + 4 Harddrives + more (full load 170 Watts) with this without any Problems (but gets warm) on a PSU-test setup.
http://img516.imageshack.us/my.php?image=fsp12yn.jpg

To save more energy you can change the ATI to a 2D-only Matrox PCI Card, i.E. "Matrox Millenium" if you dont need 3D.

have fun,
tom

 

[DigitalJunkie]

Here's a linear setup I tossed together for an AT style motherboard.
For ATX you'd need to add the 3.3V regulator,and a constant +5V For "standby".

http://www.users.qwest.net/~ptaylor/Electronics/DC-PCsupply/12Vdc_PC_power_supply.html

 

[TonyTecson]

there was a thread here about a pc psu being converted to run on 12volt car batteries, but now i can not find it! wonder where is could have been.

 

[MaXiZ]

In my opinion, inverter doesn't like the input capacitors of the pc power supply. I think that at the first moment, they look like a short circuit for the inverter's output and probably a current protection acts.

Connect a resistor between the inverter's output and pc power supply and try again. If it works you can bypass then the resistor with a relay or a triac.

Regards,
Florin

Of which value should be the resistor? Thanx

 

[Perry Babin]

What happens if you plug in both the lamp AND the computer PS (use a power outlet strip if the inverter has only one outlet)?

Does the lamp go off when you try to switch the computer on?

Does it dim significantly?

If the computer comes on while the lamp is plugged in, will it remain on if the lamp is unplugged?

 

[J.Carlos]

Maxiz, some pc power supplies needs a load to work properly (because they are regulated and regulation at light loads is sometimes difficult), maybe that's your problem, you can load for example a 5-10ohm resistor to the 5 volts output and see what happens.


Cheers
Juan Carlos

 

[MaXiZ]

What's the easyest way to obtain +3,3v?

 

[lawrence99]

http://www.mp3car.com/store/index.php?cPath=21&osCsid=2b1d57ed0b3bc5508fc9caf41cc624e2

lot of dc/dc atx mini xtx power supplys

 

[davy_shi]

design a power switch with UC3842

I would like to design a power switch with UC3842,
220vac input , 150W,
flyback structure,
multi output of +/-5v, +/-12V,15V,all are 3A.
from the datasheet of UC3842,
there are some reference circuit,
but if I want to design a novel circuit so as to get better performance.
what should i do ,a novel voltage sample circuit or other new idear about this design.
anyone who are familiar with UC3842,please give me some suggestion,