Simplest 5 Watt LED Driver.

[easy.rahil]

Hello All friends, experts,
I want to make a small and simple yet useful LED driver for power LED of 5Watt(1400mA) and 3Watt(700mA) output. and i want to use double or triple D batteries (input 3 to 4.5VDC).
If anybody can help.
I got Power LED with 25 degree View angle from Taiwan and Aspheric Lens from China to use in front of the LED.
tested 1W LED already and it gives very attractive light output with lens. more thn any other available light in market or . as they all using wide angle LEDs in their Torch and most of the light output is remains unused. see Pic. attached.( I also tested normal LEDs with wide angle) output was not good compare to narrow angle LED.

Please help making simple circuit using simple parts and if possible one feature with high/Low.
Start with without any feature but simplest.
Thanks in advance.

Wide angle led:


Narrow angle led:

 

[SABorn]

Try Ebay, China make dozens of them.

 

[easy.rahil]

can anybody give feedback for my opinion or idea?

 

[MrAl]

Hi,

What is the characteristic voltage of your LED?

 

[ronsimpson]

There are many LED drivers> Zetex/Diodes Inc, Linear Tec. to start with.

The white LEDs do not like running at 10% power to make a "low" mode. So run them at 100% power for 10% of the time. Many LED drivers (PWM) have an enable pin used to "dim" the LED or turn it off.

 

[easy.rahil]

MrAl, LED 5W Vf=4V, If=1400mA typ. and output 340 Lm, 6000K. How do you rate This specs? Quality control is grade A rating.
i even thinking of trade this company products. Degree available 25, 45, 120 in High power Series.

 

[carbonzit]

We don't care about the light output (Lm = lumens) or the color temperature. Those are your concern.

We care about Vf, the forward voltage, and If, the forward current. (According to those numbers, it's actually a 5.6 watt LED.)

Your controller needs to supply Vf at a current no greater than If.

Ron's advice about using PWM to dim them is good, too. It'll also save your batteries by not throwing away power dissipated in resistors or voltage regulators.

 

[easy.rahil]

thank you Carbonzit, but as everybody knows i know nothing about electronics. i just wanted to know if is there any simplest idea so anybody can make as DIY project with nominal parts

 

[MrAl]

MrAl, LED 5W Vf=4V, If=1400mA typ. and output 340 Lm, 6000K. How do you rate This specs? Quality control is grade A rating.
i even thinking of trade this company products. Degree available 25, 45, 120 in High power Series.

Hi again,

Well, if you have three batteries that's 4.5v, and if the LED really is 4v then that's 0.5v left, and with a current of 1 amp that would mean 0.5 ohms, but that 4.5v will load down so maybe start with a 0.25 ohm resistor in series and see how much current you get from that and run time.
If you go to four batteries instead of 3 you can get more light output, but if you want to stick with 3 batteries you'll probably need a converter and that sounds like something you dont want to get into right now. So try the small resistor first and see how you like that. Measure the current and see if it is up to what you want it to be. If not, lower the resistance. I wouldnt doubt it if you could run direct from 3 batteries but you have to be careful not to overheat the LED and burn it up in case that's too much current.
So anyway, a resistor in series or no resistor at all is the simplest, and next up is using 4 batteries instead of 3 and an appropriate larger resistor like 1 ohm.

 

[carbonzit]

The other problem with 3 cells (tsk, tsk for those who call them "batteries") is that they'll soon run down to below the minimum Vf of the LED, which will certainly dim it.

You might want to just try it out to start. See how it works, then go from there. Won't cost you anything more except time.