loading

Best driver for this led?

Sorry for posting a repeated question(i think)
Well, i'm so new to high power LEDs,
My dad bought a high power LED on ebay http://www.ebay.com/itm/160584479457?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 

The LED has the following specifications

 Working Forward Voltage (VF) : 9-12V DC

Working Forward Current (IF) :1000mA
 
Intensity Luminous: 800Lm

The seller told me to use a  DC DC converter for it. I will not pay $20 for one. 

I've seen lots of sites about the driver but most of them has circuit made for  LEDs which have a forward voltage of 2.8-3.6V.
and mine has a Forward Voltage of 12V.

So what will be the best driver for it.

I found this one but i'm wondering if this would work http://www.simple-electronics.com/2011/09/high-current-led-driver-using-fet.html

sort by: active | newest | oldest
Try this. It uses a single LM317
LED driver.JPG
ARJOON (author)  steveastrouk5 years ago
finally i decided trying to make the driver with parts that i already have.
I'm limiting the current through the LED to only 0.86A just for safety. will this type of circuit work for this LED?

Thnxs
Untitled.png
Its not great. There isn't actually any constant CURRENT control acting, except by accident.

Steve
ARJOON (author)  steveastrouk5 years ago
if i use this one
Untitled.png
The advantage of the 317 is that the sense resistor voltage =1.22 V, ad not the "regulator" voltage of whatever. As above, if this is a 12V reg, 12V is forced across R1, and R1= 1/12 Ohm. Power = 12W !

Steve
+1
ARJOON (author) 4 years ago
LOL thank you anyway for this late reply, i already finished my project and i use it everyday since with 10 AA rechargeable batteries!!! and i even made a video how to make driver for CFL and comparing them with LEDs here's the link
frollard5 years ago
You must protect the led from overcurrent. You can do this one of several ways. Starting with a 'close' voltage to the led forward voltage will reduce the waste of any resistive method you use.

An led 'at or above' its forward voltage shows up to the circuit as almost zero resistance, and ohms law says that low resistance = high current. Too high current means your led fizzles. The catch 22 is that if you add resistance through a linear regulator or resistor, you lose efficiency because those resistors burn up the excess voltage as heat.

The ideal (and not very expensive) solution is to have a switch mode power supply that uses smart switching technology to pulse the ideal amount of current through the LED -- always full on or full off, no wasted current.


http://www.dealextreme.com/p/900ma-10w-power-constant-current-source-led-driver-85-265v-42745 (runs off household mains voltage)

something a lot bigger:

http://www.dealextreme.com/p/waterproof-1a-30w-power-constant-current-source-led-driver-100-240v-48280
would drive 3 of your leds in series.

Don't forget! 10 watt leds spit out virtually 9+ watts of heat, so you need to mount them to an electrically isolated heatsink!

Lastly, GOOD leds are in the 50-80 lumens/watt range. Absolute maximum so far is a rare 80-90 lumens/watt. A claim of 800 lumens/10 watts on a cheap led is ridiculous. It's just outside the realm of possibility. Don't get me wrong, still a redonculously bright led, but don't be sucked in by the numbers.
Single chip regulators, needing nothing but an external inductor and a couple of resistors are VERY cheap, but probably hard to get on Mauritius !

Steve
ARJOON (author)  steveastrouk5 years ago
not hard to get expensively hard to get. only one place which sell it. so the retailer takes advantage of it
We have Farnell and RS accounts. PM me with your requirements, and I'll drop the bits in a padded envelope and off to you.

Steve
ARJOON (author)  steveastrouk5 years ago
no it's alright.i can buy on ebay now. my problem is not finding parts now. it takes too much time to be delivered, that's the problem.

one day i was very inspired for a project but i have quit within 3weeks, it took one month to receive only a power mosfet.

thank you again for taking attention on this problem :)
Agreed; international 'postal' shipping rather important. I grew up with a friend who moved there and back from Canada for his middle school years - rather isolated place.
ARJOON (author)  frollard5 years ago
i have 10 recheargeable 1.2V batteries in series.

So what will the best DIY driver.

It must not consist of 3 or less components. it must have lots in it but not greater than 15, just to make friends jealous of my new bike built from scratch
rickharris5 years ago
LEDs need a constant current - in your case 1 amp.

There are may electronic ways to do that and if the spec for the circuit meets the voltage and current requirements it should be OK.

Good price for a 10 watt LED although my experience is that Ebay sales tend to be below spec (that's why they are cheap) so the actual output may well be some what lower (but enough and a 10watt LED is VERY bright.)

Here are several options from Instructables.