Part Number: TPS61088
Good Day my fellow hardware guru's
I have currently a design where the TPS61088 is showing evidence of working not as advertised. I have been trying to scour the forum and read all related threads for the TPS61088.
There is currently a few problems that I have read and will investigate, but I think mine is a bit different..
1) Failure description -
Currently the power supply does operate as intended. It was designed to deliver 12V @ 15Watts from a 3.2V - 5V power supply
But we do find the unit "switched" off and not boosting. When switched off we do measure 4.5V on the output which means it is the Input voltage -0.5V diode from for the unit.. Prob "Pass Through" Mode.
This problem can not be recreated on demand which makes it even more difficult to diagnose and route cause identified.
I have confirmed that downstream CCT does not cause a high load at this stage and this power supply is then locked in this state until input power removal and re-applied.
Have confirmed with FLIR that at this stage unit is not working as it is stone cold as well as down stream CCT.
When in operation inductor and TPS61088 was measured @ full load of 12V - 15Watts with a FLIR and measured 91°C.(Bear in mind FLIR used does have a 5°C error margin)
2)
3)
PCB design - What is not seen here is that the PCB is a 12 layer design with multiple layers connected to Gnd.
4) I am not the originator of this design and reading through the threads and looking at the design notes of the PCB there is a lot of improvements that can be done.
Note
As current PCB can not be modified..
Schematic values are allowed to be modified..
Question:
What would cause the TPS61088 to go into a Shutdown state or Pass through Mode. Any suggestions would be appreciated...