W3-WallWartWizard

[IdunBenhad]

Hi:
I have been working on a regulator for Wall Warts.

The attached files show what I came up with so far.

These are in the final stages of testing and I do not expect much will change from that shown in the attachments.

This is actually a takeoff of the "Very Quiet Power Supply" posted earlier.

Read the attachment: "W3-WallWartWizard Description" first.

Any suggestions or criticisms or better ways to do it are welcome.

Edit: February 2, 2011--W3-WallWartWizard Description corrected and updated.
Edit: February 3, 2011--W3_WallWartWizard Description updated.
February 3, 2011--WallWartWizard Silkscreen updated.

[ags0000]

This is nice work. Thank you for sharing it.

Reading your W3 Description, it touched on something that I know I'll have to figure out, but haven't done so yet:

I want to eventually replace the DC-out (not sure how quiet it is) wall-wart that came with the GE RGB strands I'm using. (32 of them make for a big pile of wall-warts in a box...) I see that the rated output is 5VDC - yet when I put a Fluke DMM on it, it reads 5.6 VDC. I wasn't sure if this was a P-to-P reading vs RMS if not regulated, or that it was actually 5.6VDC out - thereby requiring me to build/buy an adjustable supply, as the "normal" output is either 5V or 12V but not 5.6V.

Can you shed some light on this? Is the output voltage I'm reading just the output under no load? What steps can I take to determine what I'll really need to build to replace the OEM supply?

Thanks!

[Jakeleg1969]

Idun, I feel sure that someone else will probably take exception to this, but I will state it anyway. I would do away with the four jumpers. Just configure the circuit as if you were running strictly AC input. The bridge rectifier will take care of the conversion to DC. Now, if you do hook DC up to the same circuit, and polarity will not matter here, two of the rectifiers in your bridge will be forward biased and will conduct, and the other two will be reversed biased and do nothing. The input voltage will be a little lower coming out of the bridge rectifier as a result of the forward voltage drop of the diodes, but only about volt. This can be made up with the adjustable regulator. Nice layout...

Jerry in Louisiana

[IdunBenhad]

Hi:
ags0000: The 5.6 volts is probably OK, as there should be some tolerance in your LED strings. Also, as you said, this may be the unloaded voltage. Do you know if this is regulated? If so, the output voltage is set and will probably not change. With that many strings of LEDs, you are going to need a much bigger supply than the W3 or the VC supply will handle. If you get a several amp supply, like a converted PC supply, you can come up will all the current you need in one small package. The purpose of these supplies I have been working on is primarily for FM transmitters and and other small current devices. Hope that helps.

Jerry: Thanks for the suggestion. I thought about that and almost did it, but decided that because the headers/jumpers were cheap, it would be better not to have the .6 to 1 volt drop for a DC WW because those darn things are so unpredictable. The problem is maintaining the differential between input and output, which needs to be about 3 volts, as you know. Thanks for the suggestion. I will probably do some testing and see how it works out with what I have here. After all, the fewer the parts, the less there is to fail.

[ags0000]

Hi:
ags0000: The 5.6 volts is probably OK, as there should be some tolerance in your LED strings. Also, as you said, this may be the unloaded voltage. Do you know if this is regulated? If so, the output voltage is set and will probably not change. With that many strings of LEDs, you are going to need a much bigger supply than the W3 or the VC supply will handle. If you get a several amp supply, like a converted PC supply, you can come up will all the current you need in one small package. The purpose of these supplies I have been working on is primarily for FM transmitters and and other small current devices. Hope that helps.


Idun: Yes, I realize this isn't the intent of your W3 design, but I hoped to piggy-back on the thread since it appears that there is some fine expertise in the forum. I haven't (yet) measured the output of the wall-wart under load. I just know that with no load, my Fluke DMM reads 5.6 VDC. My intent is to replace 32 wall-warts with one or two larger supplies, and I'm wondering if I can use standard 5VDC supplies, or if I need to find an adjustable supply and set it to the 5.6VDC I'm reading on the output of the OEM wall-warts.

[IdunBenhad]

Hi:
ags0000: I haven't done much work with LEDs yet, so I hesitate to try to answer your question. Look on the WW itself and see what it lists as the output voltage. It could be that the LED strings want 5.6 volts. That could make a difference in the amount of light output, but that is a guess. Hopefully someone with more knowledge in this area will join in and answer your question.

Generally speaking, with most devices, the difference between 5 and 5.6 volts is not noticeable, but with LEDs I just don't know.

Sorry I can't help you any more than that.

BTW, the W3 supply would be a good basis for a larger current supply by adding a pass transistor or two on a separate board and a large heatsink. You would have to have a separate transformer capable of handling the current you need. There are a lot of circuits around the web that show how to do this.

[Mactayl]

Hi Idun

Really nice job on the W3-WallWartWizard Power Sluppy, Looks like it will really clean up the Hum and noise on the Wall Warts, I like the regulator discharge protection you added. :)

[stenersonj]

i would sure be interested in some boards. thanks for the great work.

[dmcole]

Idun:

This is very nice. It would be cool if all the parts could be sourced at Radio Shack. This could be a really nice first soldering job.

I doff my chapeau in your general direction.

\dmc

[IdunBenhad]

Hi:
I've posted the W3 PC board and schematic files in ExpressPCB format under "File Library/Copper",

If anyone needs PDF files, I have them available. PM me with your E:mail address.

Thanks, everyone, for your comments. They are appreciated.

[Aurbo99]

IDun

Nice job on the W3, I'll give it a go next week.

Squeeze the pcb a bit and stuff it into one of these enclosures (http://www.polycase.com/pm2320).

[WireWrap]

...
Any suggestions or criticisms or better ways to do it are welcome.

Boy-o-boy-o-boy!! I finally get a chance to catch Idun in a (VERY) rare mistake!! :D :D



AC Wall Warts
Again the plug on the cord should be removed and the two leads connected to J1. Jumpers JP1 and JP3 should be in place, with NO jumpers on JP2 and JP4. The input is then rectified with BR1 and passed on to the remaining circuitry.
(emphasis added)

Looks like the cut-and-paste monster bit you, Idun. I think you meant:

"Jumpers JP2 and JP4 should be in place, with NO jumpers on JP1 and JP3." for the AC input.

All in good fun, but you may want to correct the description pdf file. Looks like a fine project.



:)

[IdunBenhad]

Hi:
Yep, you got me WireWrap. I'll correct the PDF and thanks for pointing it out. I thought I had proofread the thing 3 or 4 times, but I sure missed that.

I do a newsletter for the Shiners Club here in Yuma and I have a couple that delight in catching my mistakes. We have more fun over that and it makes me work even harder to get it right (which I never do). I've threatened to send it to them before I publish it so they can proofread it.

I thought I made a mistake one other time, but turned out I was wrong. Actually, Grumpy caught me in a mistake this morning. I got up.

Thanks again.