TIDUF77 June 2024 MSPM0G1507
Figure 3-40 shows waveform of inrush protection circuit when power on under 275VAC input voltage. Charging current of electrolytic capacitor C67 flow through PTC RT1, and produce a high voltage drop on both RT1 and Q1(these are in parallel), test shows that there is no current flow thought Q1 during powering on. Software can trun on Q1 to short RT1 to provide a low impedance current path after 2-3 seconds delay.