super simple high power led driver
High-power LEDs are getting cheaper, but the constant current drivers that drive them are very expensive.
Here I will show you how to build a constant current source that is simple, cheap, but very efficient.
The image shows a constant current drive connected to a 1 w White luxon LED.
Edit: this LED driver supports PWM, which means you can control the brightness of the LED (s).
This is not supported by expensive drivers.
I will post some schematic and apps as soon as I have time.
Here is a list of what you need.
LM317 regulator. a Resistor (see next step).
Radiator of LM317 (
You don\'t need to be as big as me, I just took one I lay near.
High power led of some luxon or other brands (
See the next step too).
Some wires connect it.
It is also a good idea to use the radiator for the LED.
The LM317 regulator gives a constant voltage of 1 _ 1 volt between the adjective and Vout, so by adding resistance between these two outputs, you will get a constant current.
Ohm\'s law represents U/I = R, which means that the voltage divided by the amp produces resistance.
So if you want to connect one or more luxon 1 w LEDs with a power consumption of 350 mA, the calculation should be as follows: 1. 1 (
Constant reference voltage for LM317)
Divided by 0,350 (
Led power consumption)makes 3,57.
If the resistance is 3,57, the constant current is 350 mA.
The nearest E12 value is 3,9 ohms, which will give you a constant current of 321 mA.
However, you can\'t see any difference in the light output.
If you use a 3 w LEDs with a current consumption of 700 mA, the calculation should be: 25 divided by 0,7 to get 1,78.
The closest E12 value is 1,8 ohms and the output will be 694 ma. In both calculations, the resistor must be at least 1 w.
While the rated current of the LM317 is 1,5 amps, I would not recommend it for applications that require more than 1 amp as it becomes very, very hot.
The LM350 is equal to the LM317, but it is rated at 3 AmpsI and can\'t get my schematic drawing program to work, so here\'s a hand drawn one.
The voltage drop voltage of this power supply is 3 v, so the power supply voltage should always be higher than the LED voltage 3 v, up to 37 V, which is the maximum input voltage of the lm317.
Example: you will connect two white LEDs with a forward voltage of 3,42, respectively (
In common data tables, most of them are called Vf).
The input voltage can be from 9,84 V (3,42 3,42 3)till 37V (
3,42 3,42 30,6).
You can connect up to ten high-power LEDs on this circuit.
The higher the voltage you provide to the LM317, the hotter it will be.
So it\'s not a good idea to provide it with unnecessary high pressure.