Question
Having trouble getting STUSB4500 to work properly in a Li-ion charging circuit
Connecting via USB-C with the battery disconnected everything works correctly. PD contract is negotiated, 20V is delivered and when I plug the battery in to the charger it begins charging.
If the battery is already attached when USB is connected, no PD contract is negotiated and the battery does not charge. I believe that the STUSB4500 thinks the VBUS line hasn't discharged, but I don't understand the relationship between DISCH and VBUS_VS_DISCH well enough to debug it.
Attached is the schematic. +VSINK feed to the battery charger and is at battery voltage (through a MOSFET body diode) while the battery is connected.
Any help would be appreciated! Thanks