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I want to power part of an LED strip like this one:

http://www.amazon.com/Lighting-EVER-Flexible-Waterproof-Ultimate/dp/B005JR1NUU

... from a standard US wall outlet. I don't want to use a bulky 12V power adapter. Is there a component that can do the job of converting the voltage that would be suitable for hiding in a base of a lamp? (low temp, small)

The purpose is to make an LED lamp with the power transformer hidden. The space it fits in is roughly 2" wide, 6" long and 1" tall

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  • \$\begingroup\$ Is this one too big for your application? amazon.com/Lighting-EVER%C2%AE-Adaptor-Transformers-Supply/dp/… \$\endgroup\$ – Doombot Feb 10 '14 at 20:49
  • \$\begingroup\$ Unfortunately, yes. I was looking at something like this: ebay.com/itm/… but I'm a little confused as to whether the ratings are correct for what I need. \$\endgroup\$ – kthornbloom Feb 10 '14 at 20:52
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    \$\begingroup\$ Did you read the #1 FAQ: Choosing power supply, how to get the voltage and current ratings? \$\endgroup\$ – Phil Frost Feb 10 '14 at 21:08
  • \$\begingroup\$ Phil- thank you, it was helpful to learn about this. I'm still left wondering if there's such a thing as a power supply small enough to hide. Now I know that I probably want a regulated one. \$\endgroup\$ – kthornbloom Feb 10 '14 at 21:16
  • \$\begingroup\$ The 2A unit I mentioned is taller than your size limit at 70 x 45 x 30 but otherwise smaller. Odds are there will be others of similar rating that are of slightly less height. \$\endgroup\$ – Russell McMahon Feb 11 '14 at 2:42
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Make your own from an LT3799

enter image description here

The transformer is 21mm x 21mm x 17mm approximately and I think this will be the largest part in the circuit. The MOSFET will probably be an FDPF15N65 and this is a TO220. If you still have room it's probably best to build it using the circuit in the data sheet on page 16 - they have EMC components on the power side.

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They say the power requirement is 12 Watts.
That is quite low for an 8 foot strip and it is possible that it actually draws more.
IF it is 12V rated then that's 1A and a 12V 1A switching power supply would fit in a closed fist.

Whether this is compact enough depends on what size your base is, but many map bases would be large enough.

Measuring a few real world Chinese sourced switched-mode power supplies specifically "designed" to drive LED strips.

70mm x 45mm x 30mm - 1A and 2A units (12 & 24 Watts)
115mm x 50mm x 30mm - 3 / 4 / 5 A units (36 48 60 Watts)

So, the smallest of these would operate two strips of the rating that yours claim to have. I'd expect that that would fit in many lamp bases.

150 LEDS at 12 W = 12/150 = 80 mW/LED.
Actually, that's about right - allowing 20 mA per series stringlet of 3 LEDs = 240 mW for 3 or 80 mW/LED. ie my original "too low" figure is based on what I've seen done, as opposed to what makes sense.

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  • \$\begingroup\$ I appreciate the help. I'm planning on only using part of that strip if that helps. Also added dimensions to the question above. \$\endgroup\$ – kthornbloom Feb 10 '14 at 20:56

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