Dear Support,
I almost copied the TPS61196EVM to a new design. the design goal is to drive an UV-LED chain, total 14 LED with nominal Vf = 5V. that is about 70V. so set the R21 in attached schematic to 255K(74V).
set the R43 to 19.6K to expect the Max current = 250mA.
I have checked the board when applied 24V.
the EN is 3V.
the UVLO is 113V.
I use a 200 ohm serial green LED, expect when I set the current to 200mA, I should be able to get the output around 40V. but the output is always 22V, I don't think the switching circuit start.
this is the first time that I use this chip. I hope to get some suggestion/instruction that telling me how to start diagnosis this design.
Thank you,
David