how to drive a high power LED

Thread Starter

ali sedaghati

Joined Jul 23, 2017
7
i wanna drive a high power LED with IF=360 mA
and there's a dilemma for me :))
there's two option for me:
1- use a constant voltage source and a proper resistor
2- use a driver that it's output is 350 mA

obviously the first one is much more pleasant to me
but i'm worried about that this solution reduce the life time of my led that is SO important for my project (specially when the LED heats up and it can draws more current)
can u help me please?
 

#12

Joined Nov 30, 2010
18,076
Both methods stop the LED from using more current when it heats up. Just adjust the resistor value so you do not start cold with 350.00 ma. There is no law that says you must drive an LED with the highest current it is rated to survive.
 

Thread Starter

ali sedaghati

Joined Jul 23, 2017
7
thank u SO much for your quick response
i need this for part of a project that it could leads to a producing a device and sell it in a competitive market
so as an expert could you please tell me
which one do YOU prefer for a high efficiency ( in power , in battery , in price , etc)
thank u !
 

#12

Joined Nov 30, 2010
18,076
It depends on the power you start with, and you haven't said a thing about that. A resistor is simplicity. A constant current driver compensates for variations in the power voltage. A fast switching current regulator is the most efficient, but more complicated.
You can't choose until you declare the power supply.
 

Thread Starter

ali sedaghati

Joined Jul 23, 2017
7
It depends on the power you start with, and you haven't said a thing about that. A resistor is simplicity. A constant current driver compensates for variations in the power voltage. A fast switching current regulator is the most efficient, but more complicated.
You can't choose until you declare the power supply.
well , we haven't decided this yet.
but probably a 12 V 350 mA lithium rechargeable battery.
and i'm gonna drive three high power leds that i've mentioned above.
 

OBW0549

Joined Mar 2, 2015
2,984
A series resistor is certainly the simplest and cheapest way of controlling LED current but it wastes a lot of power, especially when the input voltage is much higher than the voltage drop of the LEDs.

There are plenty of constant-current switching regulators designed specifically for driving LEDs and maintaining constant LED drive current despite variations in input voltage, while operating at high efficiency. Something like an LT3592 would probably do the job for you, but there are many others. (And that's from just one manufacturer; others have their own products.)
 
Top