Hello e2e Community,
I am using the TPS65290ZB. In my test case VIN is 3.8V (should be later sourced by battery) and I want to power a display with 5V.
When I enable the BB and BB1 (R0 with 0x05) I can measure the default ~ 4.1V (0x33). Now I write 0x37 to R3 - everything is still working but as soon as I go higher than 0x37 the TPS caused a short circuit. As load I use a 2.2k resistor.
When I use 4.5V as VIN I get 5V (0x3C) without a short circuit. It also work when I reduce the 4,5V to 3,8V after I reached the 5V output Voltage.
I'm pretty sure the test case (VIN: 3.8V BB: 5.0V) worked with the EVM of the TPS.
The power supply has a current limit from 50mA. In my first circuit I use a battery as supply but with short circuit the TPS sourced every power line (LDO,BB,etc) with 4,xV an destroy the other ICs.
My layout/schematic is based on the EVM:
As coil I use the SRN4018-3R3M, which has nearly the same specifications as the ASPI-0418FS-3R3M-T3 from the EVM. I also replace my two 33uF (6,3V) capacitors withe the one from the EVM (10V) to exclude them as a source of error. I try the same with the coil but unfortunately I broke it while unsoldering.