Hello Experts,
About the attachement from this post - TPS63051: About Soft Start issue - Power management forum
The second scope capture (Css = 101 nF) looks very similar to what I'm seeing for Vout. That is, two rising portions separated by a very long plateau. I was concerned because I didn't know whether Vout should look more "ramp-y", like the SS pin. But it sounds like everything is working fine. FWIW, here's a screenshot of what I'm seeing in the lab:
Regarding the Vout waveform: I've found that increasing Css mostly affects the length of the plateau & not so much the two rising edges. This is a bummer because the edges are what drive inrush current. So increasing Css gives a much longer plateau but only slightly longer rising edges - meaning the inrush current isn't as affected as one would hope. Does this sound like normal operation?
Lastly, I wanted to give you a heads-up that I think there's an error in the datasheet. Sec 8.3.5 says that, "Figure 3 shows the value of the soft-start capacitor in respect to the soft-start time," yet Figure 3 actually contains completely different information.
Thanks ahead for your assistance.
Regards,
Archie A.
