TIDUEY1C November 2020 – June 2025 BQ25798
To power on the TPS25751D device when the system needs to source power, the VIN_3V3 input pin must also be supplied. The TLV75533 is chosen to provide the 3.3V needed to power the PD controller. The input is connected to the TPS54531 output of 5V, which drops down to 3.3V. However, this input supply is not needed for sink-only applications and so the 3.3V rail can be omitted as well if that is the case.
Figure 2-7 TLV75533 Schematic