dc-to-dc transformer, 12v input - 5v 1.5A output

[skydiverMN]

My project is pretty simple. I'm looking to direct wire a car accessory into the fuse panel. My issue is that the car is a 12V system, but the output needs to be 5V 1.5amp. If I have a wire lead from the fusebox into a dc-to-dc transformer, then from here to my accessory this should do the trick. Sounds easy enough, but I'm not sure about a few things:

1. Is my logic sound?
2. Where could I purchase a transformer like this?
3. HOW do I ask for what I'm looking for? Is there a spec format that's best understood by people in the industry? Yeah, I don't wanna sound like a total idiot....
4. What could/should I house this all in? Does it even need something?

Thanks for your help!

 

[davenn]

There's a 3 terminal voltage reg that can easily handle 1.5A the LM338 in the steel cased TO3 type case see ... http://www.supplyframe.com/datashee...nal+semiconductor/LM338T-datasheet?id=1065427

have a look at that data sheet it tells you how to set the voltage to what you require

cheers
Dave

 

[NickS]

My project is pretty simple. I'm looking to direct wire a car accessory into the fuse panel. My issue is that the car is a 12V system, but the output needs to be 5V 1.5amp. If I have a wire lead from the fusebox into a dc-to-dc transformer, then from here to my accessory this should do the trick. Sounds easy enough, but I'm not sure about a few things:

1. Is my logic sound?
2. Where could I purchase a transformer like this?
3. HOW do I ask for what I'm looking for? Is there a spec format that's best understood by people in the industry? Yeah, I don't wanna sound like a total idiot....
4. What could/should I house this all in? Does it even need something?

Thanks for your help!

Hey skydiver,

FYI the magic of transformers is a party that only AC voltage is invited to. You are needing something called a Buck converter or DC-DC converter.

The regulator Dave suggested is a little different in that it just drops to the voltage you need and throws away quite a bit of power in the process in the form of heat(dropping 7 volts at 1.5A ~10W heater). As long as you give it some room to breathe and maybe a heat sink for good measure this will work fine and its simple. If you want something more efficient you may try looking for a buck converter module.

I will post back if I find one already connectorized.

Good luck
-Nick-

 

[eem2am]

linear.com do buck converters on a chip....LTM8030 or something like that............if you cant work out buck theory....do a hysteretic switch mode buck, as theyre easier.national.com have many ICs...........

of course, linear.com have the free simulator so you can just wire it up and watch if it works or not without the smoke