Not enough amps? $5 for the answer!

Includes but not limited to: SNES, Genesis, Sega CD, PlayStation 1, Nintendo 64, Dreamcast, Game Gear and I guess the Virtual Boy.

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JonathanMC
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Not enough amps? $5 for the answer!

Post by JonathanMC » Thu Jun 23, 2011 12:43 pm

I am finishing a N64P, but it has a big screen (8") which is making things difficult. It needs 12V, (it will NOT go lower than around 11V), but I only have 7.4V batteries. I searched for a LONG time to find a regulator but I found none. Then it was suggested use a 5v to 12V regulator, feeding off the N64 regulator. So i did that, and of course, it doesn't work right!

Basically, I am trying to run the screen off of two regulators, and it doesn't seem to provide enough amps. When i turn the screen on the power goes down to 6V, the screen goes off, then the power goes back up. How can I power my screen? HELP!?!?

Ill give $5 to the person that gives me the right answer!

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marshallh
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Re: Not enough amps? $5 for the answer!

Post by marshallh » Thu Jun 23, 2011 3:08 pm

Your problem is that you are trying to run the entire screen from a regulator that does at most 500mA @ 5v. It is already running the n64, it would make sense this would fail.

What you need to do is to build a switching boost converter to take your 7.4v straight from the battery and boost it to 12v.
http://www.national.com/mpf/LM/LM2587.html" onclick="window.open(this.href);return false;

There are many chips you can use to do this, most of them work the same way. There's a schematic for 12v in the datasheet. (Page 18)
Make sure you buy the 12v part number and its support circuitry.
Image

Snipeye
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Re: Not enough amps? $5 for the answer!

Post by Snipeye » Thu Jun 23, 2011 3:12 pm

You need this:

http://search.digikey.com/scripts/DkSea ... 587T-12-ND" onclick="window.open(this.href);return false;

Look at page 18 of the datasheet, and follow the specs they've listed there. That will let you input 7.4V (roughly) and output 12 at about 1 Amp/hour.

EDIT:

Dang, marshallh beat me to it.

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JonathanMC
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Re: Not enough amps? $5 for the answer!

Post by JonathanMC » Thu Jun 23, 2011 6:50 pm

Ok, thanks both of you, but I guess Marshallh "won" sice he answered first.
Okay, the diagram doesn't look like the picture on Digi-key, but I guess its the same?
What is the loopy line in the middle top?
What is thh symbol that looks like "play"?
Thanks to all!
Marshallh- can you PM me your Paypal so i can send you $5?

Snipeye
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Re: Not enough amps? $5 for the answer!

Post by Snipeye » Fri Jun 24, 2011 1:54 pm

Squiggly = L = Inductor = http://search.digikey.com/scripts/DkSea ... -1126-5-ND" onclick="window.open(this.href);return false;

Play = Schotky (Or someting like that) Diode = http://search.digikey.com/scripts/DkSea ... 5822GOS-ND" onclick="window.open(this.href);return false;

I trust you can find the right capacitors and resistor?

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JonathanMC
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Re: Not enough amps? $5 for the answer!

Post by JonathanMC » Fri Jun 24, 2011 2:01 pm

Snipeye wrote:Squiggly = L = Inductor = http://search.digikey.com/scripts/DkSea ... -1126-5-ND" onclick="window.open(this.href);return false;

Play = Schotky (Or someting like that) Diode = http://search.digikey.com/scripts/DkSea ... 5822GOS-ND" onclick="window.open(this.href);return false;

I trust you can find the right capacitors and resistor?
Cool thanks, that's all I need to know. I appreciate it!

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JonathanMC
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Re: Not enough amps? $5 for the answer!

Post by JonathanMC » Thu Jun 30, 2011 11:48 am

OK, I wired it up. At first it wasn't working. Then I rearranged some things and got the same voltage that was coming in. After that I changed the wiring to the regulator and now i am getting about 18V, which is too much. Any advise?

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JonathanMC
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Not enough amps? $5 for the answer!

Post by JonathanMC » Thu Jul 28, 2011 7:25 pm

Ok, it's been awhile, but I still need some help. Like I said before, if I wire it the way the diagram says, I don get any increase in voltage. If I wire it what seems to be backwards, then I get 18V. I tested the 18V and when there is a load on the regulator it shuts off, then on, then off, etc. The unregulated voltage isn't enough, so it doesn't work either.... WHY????!!!!?!?!?

Snipeye
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Re: Not enough amps? $5 for the answer!

Post by Snipeye » Sun Jul 31, 2011 3:28 pm

Pictures, pictures, pictures. If we have more details (such as pictures) we can see what's wrong and help.

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JonathanMC
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Not enough amps? $5 for the answer!

Post by JonathanMC » Sun Jul 31, 2011 4:16 pm

I will if this next thing I ordered doesnt work. Marshallh sent me a link to something else that should work. Thanks though.

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