I have been running these 24x7 for a couple years with no problems. More Comments Post Comment Categories Circuits.

High power LEDs are getting cheaper and cheaper, however the constant current drivers, to drive them are pretty expensive.

Bp3126 Led Ic How To Built A

Here, Ill show you how to built a simple and cheap, yet very effective constant current source.

The image shows the constant current driver hooked up to a 1W white Luxeon LED.

EDIT: This LED driver supports PWM, which means that you can control the brightness of the LED(s).

Ill post some schematics and applications as soon as i have time.

Bp3126 Led Ic Download Step 2

Add Tip Ask Question Comment Download Step 2: How It Works The LM317 regulator gives out a constant voltage of 1,25 volts between ADJ and Vout, so by adding a resistor between these two outputs, youll get a constant current.

Ohms law says that UIR, which means that Voltage divided by Ampere makes resistance.

The closest E12 value is 3,9 ohms, it will give you a constant current of 321mA.

If you use 3W LEDs, which has a current consumption of 700mA, the calculation should be: 1,25 divided by 0,7 makes 1,78.

Although the LM317 is rated for 1,5 Ampere, I wouldnt recommend it for applications that need more than 1 Amperes, because it gets very, VERY hot.

The input voltage can change from 9,84V (3,42 3,42 3) till 37V (3,42 3,42 30,6).

Probably not that efficient as a lot of energy will be wasted on heating up the LM317 device but still a good job.

Too much heat in the LM317 means too much input voltage.

Question.

Just accept that and change it accordingly when you make your own plans.

GilesB4 JimTheSoundman.

It is very confusing when looking at continental european data 0 RhealD1 VineethK7.

If you get creative, the power loss in the driver circuit can be cut down to almost nothing.

A switched diode capacitor combination would work quite well.

SabrinaV3.

I was skeptical that this circuit would work due to its simplicity.

Should I just connect the PWW output from Arduino to the ADJ pin Thank you in advance.

Charlie.

Either should work.

Make sure the FET is a logic level type FET so you can switch it onoff correctly with Arduino voltages.

Also make sure the FET can handle the LED current.

Type LED calculator into google and the top link is useful.

I have been running these 24x7 for a couple years with no problems.

More Comments Post Comment Categories Circuits.

Bp3126 Led Driver Ic