If you're looking for a simple high power LED driver circuit, then it's here.
Driving a high power LED is not that easy. First you've to apply proper voltage to get the maximum possible brightness and you also have to limit the current to avoid LED burn out.
You might have seen other high power LED driver circuits which consists of many parts, like inductors, op-amps, different regulator IC’s , transistor feedback networks even microcontrollers.
Those circuits are more efficient than this one. But the making expense and difficulty is much more high. So I'm showing you the simplest high power LED driver.
Part list and circuit diagram
In market, we can get 1Watt and 3Watt LED easily. 1Watt LEDs have ratings of Forward Voltage 3.2V – 3.6V, and Forward Current 300mA. While the ratings of a 3 watt LED are Forward Voltage: VF 3.4V , Forward Current: 700mA .
So we consider 3.4volts as optimal voltage, and thus the 1 watt LED is running at 3.4×0.3=1.02 watts. For a 3 watt LED it's approximately 2.38 watts.
Finally here’s the simplest high power LED driver circuit diagram.
Here, for a fixed reference supply, LM7805 regulator is used. Which can deliver upto 1Amps of current. In our cases the max required current is 700ma or 0.7Amps, so no problem there. And since the resistor “R” will be eating the extra 1.6 volts(5.0-3.4). So what would be the value of R?
Calculating the value of series resistor R : For the 1 watt model, there’s current of 300mA. So the value of the resistor should be 5.3 Ohms(appx) and wattage should be 0.48. Hence a 5.6Ohms 1/2 watt general purpose resistor will do the job perfectly.
And similarly, for the 3 watt model, the value of R would be 2.2Ohm 1.25 watt, practically you've to choose a 2 watt resistor.
You can feed any voltage greater than 5.5 volts, so we can run this circuit from a 6 volts to 12 volts supply.
Wrapping up
As I've said before, this LED driver is not much efficient, you should consider a upgraded driver in your next build, which is more efficient.
There's a good one, DIY LED driver for 5Watt LEDs, and 12V strips from 100-240 VAC .
Have any suggestion or question ? Just drop a comment.
I WANT TO MAKE POWER LED 32 NO FO 96 WATT IN PARALLEL/ SERIES CONNECTION,
SO, PLEASE TELL ME WHICH LED DRIVER WANT OT USE
I WANT TO MAKE POWER LED 32 NO FO 96 WATT IN PARALLEL/ SERIES CONNECTION,
SO, PLEASE TELL ME WHICH LED DRIVER WANT TOUSE
WHAT SHOULD BE CIRCUIT DIAGRAM
THIS IS FOR MY FISH TANK ROOF.
Dear, Arup
i want to make my own led project of 20 power leds of 3w in series.what should be the diagram & driver for this.
Can u help me please.
Thank you.
I have 30W Highpower LED 900mA 32V-34V. Do you have any Circuit?
A very power hungry and inefficient circuit for driving LED's. For the 3 Watt LED we are wasting nearly 50% of the total power in the 2.2 ohm resistor, which is absurd.
A better alternative is to use a regulator like LM317 in constant current configuration for supplying 300 mA for the 1 Watt and 700 mA for the 3 Watt LED's. Thousands of circuits are available on the internet, just google search for "LM317 constant current circuit".
I'm working on a regulated boost converter to drive LED strings, a bit complex but way more efficient than resistors or LM317
I had just connected 3 Watt led luxeon star with heatsink to mobile charger with 5v,500ma o/p working fine
Hi Gopinath,
The LED survived as the current is limited by the mobile charger itself.
What the type of the capacitors of 100uf , ceramic, eletrolitic??!?!?!?
Of course ! They're electrolytic capacitors.
Using LM7805 will not fully charge some cell phones, will keep charging at 95% only no matter how long you charge you cell phone(like Samsung smart phone(galaxy j2-j7) check your cell phone charger with a multimeter, the dc voltage will be around 6.50/or little more, because when you plug your cell phone to your charger, there will be a voltage drop. I have tested with "LM7806" not LM7805(: and works flawless. Thank you.
Hi.i wanna run 4 1w led,if i use 3.7 v battry i won't need to use drive?
And if i want these led at least 3 h work how many amp My battery current must be ?
And is it better that i hook up leds in Consecutive circuit or series?
In that case you don't need any driver. just use a 1 Ohm 1 Watt resistor in series with each LED, total 4.
1Watt LED draws around 330mA current, so for 4 LED, it's 1.32 Amp, for 3 hour backup you need 3.96Wh of energy, thats could be a 4000mAh battery. But in real life, you need around a 5000mAh battery, use two battery in parallel.