MP1584 only switching when touching COMP

I have very weird issue with MP1584, I’ve copied dot to dot DC DC converter, the one you can buy. But I’ve copied it to my PCB, and I’ve kept all components values.
However I can’t make it work properly, it only switches when I touch COMP line with a finger. I’ve even kept parts layout on my PCB to make sure it’s dot to dot the same.

I am really out of ideas what did go wrong, here is my schematics.

ok I figured out that I’ve messed up R27 value. changing that appears to work

Yes, resistive network needs to be sized properly to have stable output. FB pin plays a crucial part in output regulation. Good that you caught it.


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