Author Topic: Question regarding creating a USB charger...  (Read 5349 times)

Offline timxirish

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Question regarding creating a USB charger...
« on: July 04, 2011, 04:04:36 PM »
So I think it's common knowledge that the power line in USB is 5v, right?

I'm planning on modifying my DSi LL's power adapter to also have a USB connector like what I did with my DSLite.

The problem is the DSLite's input is (If I recall correct from memory) 5.2v and the DSi takes 4.6v. I felt it was reasonable to assume that giving the DSLite 5v wouldn't damage it, and after a year of charging it via USB, I'm pretty sure it's safe.

However on the DSi, I don't think giving 5v to something that wants 4.6v is a safe decision. I thought maybe if I used a resistor to step the voltage down to 4.6v, it would be safer. But is a resistor really what I want? Or would someone more knowledgeable on electronics recommend using something else instead of the resistor?

Thanks in advance.
« Last Edit: July 04, 2011, 04:05:38 PM by timxirish »

Offline hyper999

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Re: Question regarding creating a USB charger...
« Reply #1 on: July 05, 2011, 08:13:10 AM »
Not sure and I'm sure one of our EE's will jump in here but a diode is probably the best way to drop the voltage here. A diode, when put in series, will drop the supply voltage to the ds by 0.6 volts.
« Last Edit: July 05, 2011, 08:13:47 AM by hyper999 »

Offline frenulem - No.5417

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Re: Question regarding creating a USB charger...
« Reply #2 on: July 05, 2011, 05:34:22 PM »
Nail on the head hyper, put a diode in there and it will drop by 0.6V

Offline timxirish

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Re: Question regarding creating a USB charger...
« Reply #3 on: July 05, 2011, 11:47:36 PM »
Is there any specific type of diode I'm looking for? Aside from light emitting diodes ( :p ), I have no idea what the different types are, or which I should go with. (ie. zener diode)

Also, any specific specs should I be looking for? (or instead, any specs I should avoid?)

Thanks again guys, really appreciate the replies. I'd be more than happy to donate a quality pictorial in return.

Offline frenulem - No.5417

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Re: Question regarding creating a USB charger...
« Reply #4 on: July 06, 2011, 12:50:13 AM »
Just your regular silicon diode, Zener diodes are mainly used for ac currents and things, if I can pull a part number somewhere I will but right now I'm having breakfast with my dad lol

Offline timxirish

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Re: Question regarding creating a USB charger...
« Reply #5 on: July 06, 2011, 02:45:56 AM »
Hah, alright, would be much appreciated. Radio shack (ew, i know) or mouser preferred, but i'll take what I can get.

In the meantime, enjoy your breakfast. :)

Offline frenulem - No.5417

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Offline timxirish

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Re: Question regarding creating a USB charger...
« Reply #7 on: July 07, 2011, 01:26:35 PM »
Cheers man, I picked one of those up yesterday while I was at work. I'll probably install it tonight or tomorrow (taking crisp pics as I go).

My only concern is that the package claims a voltage drop of 1.6v ("forward voltage drop"; i assume it to mean the same thing?). But the worst that could happen is the DSi will slowly charge or not charge at all. If it's considerably slow, I may try searching around for a "silicon diode" with a 0.6v drop.. I can always change it later anyway. :)

Bottom line is nothing beats the convenience of being able to charge with USB. I feel pretty damn rude if I take up more than one outlet in a public place, so this will make things easier.

Anyhow, this is what you can expect when I'm finished:
[spoiler]
http://i54.tinypic.com/bfrryo.jpg
edit: looks like I can't post images. oh well.[/spoiler]

I had to trim a little corner of the DSLite's AC adapter's PCB to make it fit, but that's half the fun :). I'm half expecting to do the same with the DSi power adapter, but we'll see how that goes.

Thanks again man!
« Last Edit: July 07, 2011, 01:27:49 PM by timxirish »

Offline frenulem - No.5417

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Re: Question regarding creating a USB charger...
« Reply #8 on: July 07, 2011, 05:42:32 PM »
:censored:, i screwed up man i was going to put up a silicon diode, thats what i should have sent you

Offline nEoVaLoR

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Re: Question regarding creating a USB charger...
« Reply #9 on: July 07, 2011, 07:50:30 PM »
You aren't going to use mini usb??? D:

Offline timxirish

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Re: Question regarding creating a USB charger...
« Reply #10 on: July 16, 2011, 07:07:10 PM »
:censored:, i screwed up man i was going to put up a silicon diode, thats what i should have sent you
No worries, if it doesn't work I can fix it relatively easy. Is there a different one you would recommend then?

You aren't going to use mini usb??? D:
Nah, I realize the usefulness of adding mini USB, but the perfectionist in me is holding me back from doing it. I want to keep my case as virgin as possible, only because it's a Japanese import (DSi LL). If I did that, I would have to modify the bottom housing (which is the only housing piece externally different from a US DSi XL).

If I knew I could make a perfect professional cut, then i'd definitely do it. I may also consider it if I can get a Japanese housing replacement. I would probably do a overclocking switch too.

Offline frenulem - No.5417

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Re: Question regarding creating a USB charger...
« Reply #11 on: July 17, 2011, 06:00:17 AM »
go for the silicon diode, thats the one you need

 

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