Other Parts Discussed in Thread: LM3405
Hi,
we have an application where we want to use the LM3404 to drive one or multiple LED string in parallel. The LED strings are remote. We want the same current on all the strings. To get that we have put the same Rsns in series to all the string and connected the Vsns together like this:
Note all LEDs in the strings are the same all the strings have the same number of LEDs and all Rsns are the same Vo are connected together as well. We have been using this kind of design with the LM3405 and we were able to make it work. However with the LM3404 when we scope Vsns we see a lot oscillations. The LEDs strings still light up. Are the oscillation detrimental to the device? If so, do you have any suggestion on what could cause such oscillations and how could we avoid them?
This is Vsns with LM3404:
This is what we were getting with LM3405: