Tool/software:
Dear TI E2E support team,
I am using the USB-controller's LDO_3V3 output pin to wake up my system when USB-C is connected. Once the connected MCU is awake, 3.3V power supply is provided to the USB-C controller's VIN_3V3 pin from outside and a patch is loaded through I2C. This works fine, but I'm having a problem shutting down when the USB-C device is still connected.
During system shutdown, the 3.3V supply is killed by the MCU which unfortunately causes LDO_3V3 to drop to zero as well. It seems like the TPS25750 then notices that VBUS is still present and powers LDO_3V3 from VBUS instead after a dead time of ~100ms. Problem is that this positive edge on LDO_3V3 wakes up my system again.
One possible solution would be to force the TPS25750 chip to use VBUS as supply for LDO_3V3 before killing the 3.3V supply from outside. This would mean that LDO_3V3 would remain constantly high and my system could shut down as desired (except TPS25750, which is OK). Is it possible to set the "dead battery flag" somehow through I2C or any other way to force LDO_3V3 to remain high in this scenario? Maybe even by loading another configuration patch? I measured that swapping power input between VBUS and VIN_3V3 doesn't cause any voltage drops in LDO_3V3 when no patch is loaded.
In case this is relevant: device Configuration using ADCIN1 and ADCIN2 is 'AlwaysEnableSink'.
Thank you very much in advance!
Fini
