# Cree Circuit Board

Hi,I just want to know what a Cree Circuit Board is?Can this be used to connect a cree led to mains 220 volt AC?

4 years ago
Cree(r) is a brand name. It is the name of a company that makes high-powered LEDs.
http://www.cree.com/

So really what that link is describing is a constant current regulator intended for powering a single white LED, at a constant current of 1.25 A.

The typical forward voltage of a white LED is approximately 3.6 V, and when I multiply those two numbers for voltage and current together:
(1.25 A)*(3.6 V) = 4.5 W
I get an answer that is kind of close to 5 watts.  So that sort of serves as a check on the numbers, because they're selling that board as a "5W" board for driving a single high-powered LED.

The input voltage that particular regulator board wants is anything in the range 3 to 18 VDC, so that is NOT mains power, NOT 220 VAC.

To find a led driver board from DX that will run on mains power, try the search:
http://dx.com/s/ac+led+driver

Then look for one that will supply the amount of constant current you need for your LED.

I should probably say a few more words about current(amperes) and power(watts) ratings for these things.

DX is doing sort of a funny thing in the way they sell these driver boards.  They rate them in terms of power (watts) and the number of LEDs in a series that the board is intended to drive.

For example this board,
http://dx.com/p/3w-power-driver-for-led-light-bulb-ac-90-265v-82748

is sold as a "3W" board, but it is NOT intended for driving a single LED at 3W (which would be about 0.9 A of current).  Instead it is intended for driving 3 1W LEDs in a series (at 0.3 A through the whole string), and you kind of have to read the details to figure that out.

Even worse is this one:
http://dx.com/p/330ma-7w-led-constant-current-source-power-supply-driver-90-265v-81778
where the description does not bother to mention what the current setting is. Although it might be "330ma" since that string is part of the URL.

Obviously the honest way to do this would be to just specify the current setting (It is a constant current regulator after all.), and also the maximum voltage at this current, which would tell you the maximum number of LEDs you could stack in a series string.

Of course DX's saving grace is that they have really good prices, even if their stuff is poorly documented, and takes months to arrive.

Anyway, I hope you find what you are seeking.