TPS25751D datasheet(33/89 Pages) TI1

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VOVP4VSYS = VOVP4RCP / rOVP

Power Path Supervisor

VOVP4RCP

Figure 8-14. Diagram for OVP Comparators

8.3.3.2.2 Reverse-Current Protection (RCP)

The VSYS gate control circuit monitors the PPHV and VBUS voltages and detects reverse current when the

VVSYS surpasses VVBUS by more than VRCP. When the reverse current condition is detected, GATE_VBUS is

disabled within tPPHV_RCP. When the reverse current condition is cleared, GATE_VBUS is re-enabled within

tPPHV_ON. This action limits the amount of reverse current that can flow from PPHV to VBUS through the

external N-ch MOSFETs. In reverse current protection mode, the power switch controlled by GATE_VBUS is

allowed to behave resistively until the current reaches VRCP/ RPPHV and then blocks reverse current from

PPHV to VBUS.

-VRCP

1/RPPHV

VRCP/RPPHV

V=VVBUS ± VPPHV

Figure 8-15. Switch I-V Curve for RCP on Sink-path Switches.

8.3.3.2.3 VBUS UVLO

The TPS25751D monitors VBUS voltage and detects when it falls below VVBUS_UVLO. When the UVLO

condition is detected, GATE_VBUS is disabled within tPPHV_RCP. When the UVLO condition is cleared,

GATE_VBUS is reenabled within tPPHV_ON.

8.3.3.2.4 Discharging VBUS to Safe Voltage

The TPS25751D has an integrated active pulldown (IDSCH) on VBUS for discharging from high voltage to

VSAFE0V (0.8 V). This discharge is applied when it is in an Unattached Type-C state.

8.3.3.3 TPS25751S - External Sink Path Control PP_EXT

The TPS25751S has two N-ch gate drivers designed to control a sinking path from VBUS to VSYS. The charge

pump for these gate drivers requires VBUS to be above VVBUS_UVLO. When a sink path is enabled, the

circuitry includes a slew rate control loop to ensure that external switches do not turn on too quickly (SS). The

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TPS25751

SLVSH93 – OCTOBER 2023

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