I have a customer asking the following:
I have been playing with the eval board you got for me, and am having issues getting it running.
I’m trying to drive a single 12V LED @ 1A.
I replaced the current sense resistors with .22OHM resistors according to the equation given in the datasheet.
I also replaced Rfb1=10kOHM and Rfb2=2.74kOHM, this should give me a Vdhc_ready=12V…. that part appears to be correct as I see ~2.5V at the Vfb_led pin @12V in.
I have the Enable pin floating, as the datasheet indicates there is an internal pullup… I only ever see about .96V on that pin though.
In addition, the VCC pin never rises above ~2.2V.
I have tried a Vin of 12-20V with the same results. Any idea what I am doing wrong here?