Hi all,
I am using the STUSB4500 to power a device with a large inrush current. I have configured the PDO's for 20V @5A which should be more than sufficient to meet the power requirements. I have selected POWER_ONLY_ABOVE_5V so that it will not attempt to power the device at 5V (which would draw 4 times as much current). See my settings below:
However, when I connect a 100W USB-C PD adapter to the circuit I see the chip first negotiate 5V before switching to 20V. I think that is expected but what I did not expect is the VBUS_EN_SNK to pass through the 5V. I believe this is causing the overcurrent protection to trip on the USB adapter (after a short delay) so we see the power turn off shortly after the switch to 20V. In the below scope trace the yellow is VBUS and the cyan trace is VSink (see schematic attached).
Has anyone run into this issue? Any idea what I might be doing wrong?
Let me know if I can provide any more details.
Best regards,
Phil
