Dc to DC powersupply

[Crash893]

okay i got a 12v line coming inf ( from a car)

car power is pretty darn dirty from what i hear


i need a power supply that will take 12v from a car ( i dont need it to be like a cig lighter type deal i can splice it in)

and give me atx power some where around 100-150 watt would be fine.

any suggestions

and most importanly any links

[Turd Furguson]

Well I know if you add some capacitors it will filter out all that noise. Not sure as to how big the cap would have to be.

[L337 M33P]

www.smpstech.com <--- design behind switching power supplies

you would need to filter the input anyway as switch mode power supplies generate lots of noise if not filtered properly. There are a few caveats in building these sorts of things -

1) This is a serious design challenge if you can't buy one. Lots of maths is involved in calculating component values and sizing stuff.

2) It will only be as good as your weakest link and is most likely to fail where components are stressed - in the case of high current supplies there is a lot of emphasis on the internal impedance of the capacitors used to smooth the supply output, so often many caps in parallel are used. MOSFETs and coils are also the components under stress.

3) Cost - it will probably cost a lot more than just the value of the components added up, in both time and money. Make sure you have both to spare.

I know cos I have built an audio amp and am planning to build a regulator similar to the one you specified. Also as a side project I want to build a 35A 12V mains supply (Switch mode)

[Crash893]

yes but both of you over looked one reqirement

that it be atx compatiable.

[Oklahoma Wolf]

Some PSU makers have dc-dc ATX units, but I have no idea where to find them. The only one I can think of ATM is Channel Well who makes 250w and 300w units, but even the regular AC CWT units are hard to find on this continent. Best thing I can think of is to email the manufacturers and find out where you might get your hands on one. I know there are others besides CWT, but can't think of them for the life of me (long day).

Here's the link to CWT's website: www.cwt.com.tw

[larva]

The only DC versions Sparkle makes run off of 24 and 48V. These are only 150W ATX supplies. It sounds to me like the current level gets out of hand below 24V, I'm not sure what you want exists.

[Oklahoma Wolf]

Just realized the CWT models are 24 and 48 as well - dang :(

[L337 M33P]

Originally posted by Crash893
yes but both of you over looked one reqirement

that it be atx compatiable.

Buy $5 250W noname ATX PSU

Gut 250W ATX PSU - junk the components and use the molexes as spares.

Keep the case :)

[petreza]

what exactly do you need the computer in the car for?

If it is something that does not need too much processing power (mp3), then you can get one of THESE (http://store.ituner.com/ituner/posoformi.html). I have the PW70 for my mini-itx board and it can handle the board plus one regular HD. If I add my DVD burner to the system, it would boot but as soon as I insert a CD or a DVD it would reboot. I see now that they have the PW70A which should be able to output 100+ Watts giving you a greather flexibility.