Hello,
I have technical issue with a Boost application 44V/17A, with TPS40090 controller (Boost designed from the PMP9637 application).
The controller enter in hiccup mode immediately after the soft start pin reach 1V, even with no output current. I suspect noise problems on output which disturb the Feedback voltage but I don't know the source of these perturbations and how to fix them.
Have you ever had similar problem and did you know how to fix this problem?
I made a lot of tests but the problem persist.
A 1nF capacitor put on output allow up to 1.3A output current without hiccup but the output remain noisy and the controller switch in hiccup mode with more current consumption.
The HF noise on output occur during MOSFET switching. The design was made initialy with PSMN4R3-100ES N-channel MOSFET, I replace them by CSD18533KCS (closest to the application note) but there is no improvement.
My schematic and some oscilloscope screenshots :
Schematic :
Capture 1 : Hiccup mode with no load connected on output.
Capture 2 : Output voltage with 1.3A (with 1nF capacotor connected on output)
Capture 3 : Driver's output (U13) with 1.3A output current. (Same kind of signals on other driver's outputs)
Capture 4 : Driver's output and MOSFET's drain with 1.3A output current
Captures 2,3 and 4 was taken with a 1nF capacitor connected to output and CSD18533KCS MOSFET for U10,U14,U15 and U16.
Thank you for the consideration and the time spent on my problem.
Best Regards.
Jérémy
