Hello everyone,
I am planning to drive a 1W 150 mA UV LED with an Arduino UNO.
I’ve read some posts and understood that driving from the pin wouldn’t give it enough juice and running a set of resistors would likely burn out my LED.
What would be an ideal and safe way to drive it?
I’ve also attached a photo of the specs of the LED
Use a transistor as a switch. Example:
It looks like your LED is an assembly, with built in current limiting, so R1 above is not needed. And use 5V to power it.
I don't see that. It has an aluminum heatsink base. But I don't see anything about current limiting...
The specs say 5V forward voltage measured at 150 mA current. It is not clear how that is accomplished.
5V reverse voltage.
Check again.
Forward voltage? That is just the junction drop. Could be two LEDs in series.
It is NOT CLEAR how that is accomplished.
Especially if you can't read Hanzi. 
Would it help clear the confusion if I provided more details about the LED?
Thank you also for the replies
If you were to post a link to the data sheet, forum members could decide whether the confusion is cleared.
Yes.
Peak wavelength is 250–260 nm, it's an UVC LED.
Don't think there's any internal resistor.
Like all diodes, LEDs are non-linear (their resistance changes inversely with voltage) so they are normally "current driven". With the correct current the voltage "falls into place" and everything is good. If the voltage is slightly-low the current becomes way-low and if the volage is slightly-high the current becomes way-high and things burn-up!
Of course, you have to have enough voltage available and 5V won't be enough if you put a current limiting resistor in series.
Most "high power" LEDs are driven by a special constant-current switch mode power supply (or driver). Thats' not an easy thing to build. 
"Regular little" LEDs normally just use a current limiting resistor.
jremington's circuit should work but I calculate 40 Ohms for the resistor. And you'll need a 1W (or more) resistor. (Power = Current squared x R) This is the downside to using a resistor... The resistor wastes power (converting it to heat) so it's inefficient.
The voltage gets divided between the LED and the series resistor (12V is shown) so we use Ohm's Law to calculate the resistance based on the voltage and required current.
The Arduino I/O pins are rated for 40mA "absolute maximum" and with a 1W LED you are more likely to burn-out the Arduino (not the LED) and/or you won't get the full 150mA so you won't get full brightness. Or, since the LED is rated for between 5 and 7V, you may get much less current (and much less light output) with only ~5V.
Sounds like an expensive LED.
I would use a constant current LED driver for that.
This driver would be perfect after replacing the sense resistor with one calculated for 150mA.
That would be 0.68 ohm for R2 instead of 0.3 ohm, and remove the other (unused) 0,3 ohm.
Use a 12volt supply for that driver.
I assume you are able to solder smd parts, because the LED also is smd.
The 1watt LED needs a board with enough copper on each side of the LED !!!
Leo..
if it is correct, please tell me you will use it with safety (like protecting your eyes for direct and/or long time exposure).
you should now you can't detect its wavelenght with bare eye and won't be able to directly see if the led is on or not.
Actually, I think it will be dimly visible, but I also thought, that is going to be a serious vision hazard, could easily lead to permanent eye damage or blindness.
After all, the request was for a
safe way to drive it
Didn't notice that. Quite the dangerous LED! Instant skin burns, close up.
And eye damage? Of course!
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