Hi
I hope somebody can help me, I have used an LM3407 to drive an LED module, I have a 6 LED version and a 3 LED version ( same PCB with links)
These are both powered from a 30VDC supply and multiple LED modules can be attached to the 30V supply.
I used the exact circuit from the evaluation board reference design
I have found the driver is noisy in the 100-200mHz range, reducing the switching frequency to 300kHz is better but it still fails EN 55015 EMC tests.
I have fitted a common mode choke to the 30V DC input, this helps a lot but is still not enough to pass.
I found fitting a common mode choke to the LED string greatly reduces the Radiated emissions ( I will test this in the lab next week)
My question is can this cause any problems to the operation of the driver?
many thanks in advance for any help.
