I'm trying to decide if I should use an LED driver in my project or not. My board is a microcontroller + radio running on 3 AA batteries and I'm trying to drive 3 white LEDs rated for 3.2V @ 20mA each.

Would it be more power efficient to run each of these LEDs with PWM off their own output pins, or to connect them in series and drive them using a PWM compatible LED driver like this one? I'd like to avoid using this driver if possible, as the switching current it creates sometimes causes problems with the radio that I'm using (nRF24L01+). However, battery life is the greatest concern that I have.

Thanks!

 

That looks like a good choice for a driver. It is rated for PWM use, and it avoids the waste of battery power that a series resistor would entail.