Mobile Power (12V, 575A) and conversions (5V, 2A)...

[iD10T]

I have a project I want to work on and I figure that the most knowledgeable people on electronics would be those who KNOW electronics! So, after searching, I found here! Thanks for being here, answering questions for Noobies and just being cool...

My problem (If you would help...): I need to make a standard 12V cigarette lighter adapter output only 5V, 2A. But, (And you know there is ALWAYS a but with this kind of stuff!) I need to make it stable. As to NOT destroy my electronics! And I'd like to be able to squeeze it into a "common" lighter plug, similar to this:

**broken link removed**

So, how would I go about doing it? Schematics would be cool, but a general understanding and a prod in the right direction would work good too.

(I have done searches until I'm blue in the fingers and only one place had what I needed but doesn't sell it anymore. eBay doesn't carry anything like it and all of the "Universal Car Adapters" jump from 4.5 to 6V and almost never approach 2A! Besides, what would I do with all of this solder?!)

Thanks In Advance!

 

[iD10T]

And now I'm actually searching the forums. D'oH!

(I USUALLY do that first, but I got excited!)

EDIT: Well, after searching, I've discovered the ability to use a 5V voltage regulator. Any suggestions as to a model while keeping the 2 amps in mind? TIA

 

[Nigel Goodwin]

And now I'm actually searching the forums. D'oH!

(I USUALLY do that first, but I got excited!)

EDIT: Well, after searching, I've discovered the ability to use a 5V voltage regulator. Any suggestions as to a model while keeping the 2 amps in mind? TIA

It will make it quite a lot more complicated, but you will need a switchmode regulator! - a simple linear regulator would require heatsinks too large to fit in your required casing. If it's outputing 5V at 2A, the regulator will dissipate 14W of heat at (2A x 7V).

What are you actually wanting to feed?.

 

[iD10T]

An awesome little gizmo, called the Sharp Mobilon HC-4600 Pocket PC. It has WinCE (hehehe... WINCE!) and Pocket Excel, which I'm particularly interested in using for navigation of streets and roads while driving. It's a set course (Rural paper route. I know... funny.) and I needed the ability to see different directions for different routes. It turns out to be the best option.

The battery supplies 2.4V @ 1.8A according to the underside of the unit, but the AC charger (Unique wall wart!) supplies 5V, 1.4A. The unit is rated for up to 2.0A for consumption of power using the backlight.

Any model numbers and connection hints for that switchmode regulator would be awesome! Thanks.

 

[zevon8]

I would be tempted to buy a general purpose adapter, and put a new device plug on it.

Here is a sample of what I mean:

**broken link removed**

 

[Someone Electro]

The thing is 500mA short.So the regulator may overheat,blow the fuse or triger an overload protection.

Meaby an switch mode PSU like niger seed..Switch mode suplys are small and light but powerful and eficent.The PSU in a PC is switch mode becose it needs to provide the huge 400W (Im curently using one to power an old aduio amp riped out of an radio,so im listen music whith it.Whith an low freqency filter it make the bass sound great)

It wod be cool to have an solar charger for it.

I also have WinCE on my mobile phone (Its caled:Windows CE smartphone 2003 to be exsact) The best thing is BetaPlayer that plays mp3 and other formats from an SD/MMC card and has bass setings to make it sound good.

 

[iD10T]

I considered the idea of using a plug and then just placing the adapter I need on the end. But I kind of wanted to make it "not messy". You know, too many wires taped up and stuff.

So, if I were to use a switchmode, what could I use efficiently and without maximum fuss or wires hanging everywhere? Also, about a computer PSU, how would you go about making that work when the input is going to be DC 12V, not AC?

Thanks again for the suggestions and help!

 

[Someone Electro]

Switch modes converit it to DC and back to AC (high freq.) thurgh a transformer and then back to DC agen.The whole trick is using high freq to drive an tramsformer.This way the transformers can be realy small and powerful.

PC PSU can run from DC but you need a minimum of a 100 V.

Switch modes are realy eficent and powerful they ouput 5V at about 25 A wich is enormus power.

Switch mode PSU is also now usend in cell phone cargers.


If you want it simple just mount an high power liner regulator on an big heatsink whith meaby an fan or if you want it compact use an swich mode wich is more complicated.