LM3407MY/NOPB

HENRY SCOTT

Prodigy 30 points

Other Parts Discussed in Thread: LM3407

hello,

I am projecting a led driver 350mA using the

LM3407MY/NOPB

By webench I have project it, it's a 24Vdc power supply, with 2 Osram led 3.1V 350mA.

I am testing it, but it is right up to 16Vdc, from 16 Vdc to 24 Vdc I see the light is very low.

Is righ to use the LM3407 in this condictions? because, I see on Webench, also by flowchart, it will work right, but really it is not.

Can someone help me?

Thanks

Henry

over 10 years ago

0 Leo Bosch over 10 years ago

Guru 23000 points

To me it looks like you hit the (internal) switch current.
Check Risns for proper value and board layout/location.
Check L1 for proper value. Try to increase L1 to a next higher value.

0 HENRY SCOTT over 10 years ago in reply to Leo Bosch

Prodigy 30 points

Rsins by Wenench is 0.560 ohm, capacitors is like the project, I check 22uH, 33uH , but up to 16Vdc led light is ok, from 16Vdcto 24Vdc the current decrease, and after 5 minutes it is on, light alternatively on, and off. Rfs 55.6 Kohm. What can I change?

0 HENRY SCOTT over 10 years ago in reply to Leo Bosch

Prodigy 30 points

0 Leo Bosch over 10 years ago in reply to HENRY SCOTT

Guru 23000 points

Difficult to say what your problem is without more information as schematic and PCB layout, if possible post them here.

Power management

Power management forum

LM3407MY/NOPB

LM3407MY/NOPB