power circuit to drive HB LED

Hi everybody,

I have a micro controler (Arduino mega) and I'd like to drive Hi power LED (3.4v 0.7A).
Also,I'd like to dim the brightness with a very fast PWM signal (more then 20 khz).
At the end, I need 14 channel like this.
My electronic knowledge is very bad and I wonder if someone could help me please.

here is what I found at the moment
https://www.electro-tech-online.com/custompdfs/2010/08/MAX16832-MAX16832C.pdf
It's a LED driver with a PWM input
Do you think I'm in the right Direction?

cheers