Choosing a transistor for high power LED application

[ElectroPhilip]

Dear all,

First of all, hi I'm Philip and nice to meet you all
I'm a designengineering student from Delft.

My question is farily simple, I'm looking to make a dimmable high power LED setup.
The LED chould be dimmable by using the PWM signal from the arduino.

Something like this;


I want the driver to be a constant power supply, with some sort of transistor to act as a gate.
This gate should be PWM controlled by the Arduino to give it a illusion of dimming (where in fact it's the duty cycle variation).

I've done similar setups before with simple low-power LED's, but I'm not sure on picking a transistor for this setup, in which a lot of current will flow through the transistor.

Thanks for your time!

Cheers,

Philip

 

[kam1787]

I think you have to tell us what current [and voltage]....................

Saying "a lot of" current is too vague

If you don't know you could give some specs on the voltage and LEDs [and their configuration]


BTW is there a reason for using an Arduino? Seems like over-kill.

 

[Audioguru]

If the LEDs are in series and use 48V at 1A then a transistor cannot be used because it will need 100mA at its base to fully saturate. The Arduino can supply only 25mA.
Use a logic-level Mosfet to switch the power supply to the LEDs modulated by the PWM.