Voltage Regulator And Transformer Question

[mymixed]

Hey everyone,

I would like to make a power supply for my macbook (reason), but I am wondering what regulator I could use. I have been looking for a switching regulator that will regulate 110v AC (1.5ah) to 16.5v DC (3.65ah). I know how to convert AC to DC but what I can't find is a regulator that regulates down to 16.5v. Also, how would a up-convert the amperage to 3.65ah? Thanks for the help,

- mymixed

 

[Snipeye]

Re: Voltage Regulator

"up-convert the amperage" isn't really a matter. Wall socket provides 110V and 1.5Ah, I.E., 165Wh. 165Wh @ 16.5V (convenient division!) = 10Ah, assuming 100% efficiency (which doesn't actually happen). However, even at a pathetic 50% efficiency you'll still have more than enough provided.

If you use a LOT of resistors in parallel (Unless, of course, you WANT to fry them) and bump the DC voltage input down to 90 or so, here are 5 chips that you might be able to use (I didn't look at the datasheets, just filtered these parts out).

http://search.digikey.com/scripts/DkSea ... D%23PBF-ND
http://search.digikey.com/scripts/DkSea ... G%23PBF-ND
http://search.digikey.com/scripts/DkSea ... G%23PBF-ND
http://search.digikey.com/scripts/DkSea ... S%23PBF-ND
http://search.digikey.com/scripts/DkSea ... N%23PBF-ND

 

[XCVG]

Re: Voltage Regulator

This one, perhaps? http://focus.ti.com/docs/prod/folders/p ... 8020h.html

Of course you would need a beefy transformer to feed it. 24V should work if I read that correctly.

 

[mymixed]

Re: Voltage Regulator

Great. I'll check those out!

- mymixed

EDIT: I think i'm going to use the PTN78020HAH. This will work right? I'm getting the free sample from ti.

 

[mymixed]

Purposeful Double Post:

So I've bought the regulator as described above, but I have a question about the transformer. I need a transformer that is 24v and greater than 60VA. I would like to use a 90VA transformer just to be safe. Anyway, I don't no where to buy one! I've looked at a few websites but they all have a very limited selectional. Where do you guys get your transformers? PC Power supplies? Any help would be greatly appreciated.

- mymixed