ZHCSGV1C June 2017 – March 2018 TPS25740B
PRODUCTION DATA.
ENSRC may be connected to the enable pin of the power supply as shown in Figure 40. This configuration can eliminate the idle state power loss in the power supply by only turning it on when a sink is attached. In this configuration, VPWR must be connected to a live source so that the TPS25740B can wake upon sink attachment.
Another benefit of this configuration is that only one NFET is required to block the source capacitance of the power supply when the socket is cold. This requires that the NFET be oriented with drain towards the type C connector as shown in Figure 40. For this NFET orientation, TPS25740B cannot protect the power supply from over-current events, so the power supply must implement over-current protection. For this case, RS may be removed with ISNS directly connected to VBUS. Since VBUS follows DC OUT, power supply start-up overshoot must be less than V(SOVP5). ENSRC is set to high-z after a delay of tHR whenever TPS25740B detects a fault that requires a hard reset.