MP1530 VGH stuck at 13.9V, should be 18V

DC-DC Power Converters
1

Hey all, bit stumped here. I have a MP1530 driving a few LCD supplies and Vmain and VGL work fine but VGH isn’t getting as high as we need.

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It does assert REDYn so it thinks it’s where it needs to be but VGH is measuring 13.9V vs the 18V expected.

Using Vfb3 as 1.25 and the equation in the datasheet R13 and R10 look right?

Probably something silly, any thoughts? Thanks.

2

I’m only seeing 0.97V at FB3, which is logical for the VGH of 13.9… Maybe my resistor values are too large?

3

Nevermind, the diodes are all messed up and I’m missing two caps. works fine after rework.