For our PCB we are using the TPS65131, however it does not work the way we expect it to.
As a starter our Vpos is at a steady 10V instead of 15V
And Vneg is either 0V or it jumps to -7 V and then slowly goes back to 0V and that jumps to -7V again. See picture below(yellow line)
Further more the Vref is -0.5 V not the 1.213V listed in the data sheet. See picture below(yellow line)
The FBN is also -0.5V, while it should be 0V.
The FBP should again be 1.213 V, but it is around 0.8 V. See picture below(yellow line)
We did alot of test, checked al the soldering, checked if we did therest right. But we are quiet stuck. Does somebody reconize this behaviour and can tell us whats wrong.
