TPS25751D datasheet(32/89 Pages) TI1

32 / 89 page

8.3.3.1.7 PP_CABLE Local Overtemperature Shut Down (OTSD)

When PP_CABLE clamps the current, the temperature of the switch begins to increase. When the local

temperature sensors of PP_5V or PP_CABLE detect that TJ>TSD_PP5V, the PP_CABLE switch is disabled and

latched off within tPP_CABLE_off. The port then enters the USB Type-C ErrorRecovery state.

8.3.3.1.8 PP_CABLE UVLO

If the PP5V pin voltage falls below its undervoltage lock out threshold (VPP5V_UVLO), then the PP_CABLE switch

is automatically disabled within tPP_CABLE_off.

8.3.3.2 TPS25751D Internal Sink Path

The TPS25751D has internal controls for internal FETs (GATE_VSYS and GATE_VBUS as shown in Figure

8-13) that require that VBUS_IN be above VVBUS_UVLO before being able to enable the sink path. Figure 8-13

shows a diagram of the sink path. 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 TPS25751D senses the PPHV and VBUS

voltages to control the gate voltages to enable or disable the FETs.

The sink-path control includes overvoltage protection (OVP) and reverse current protection (RCP).

PP_HV

Gate Control and Sense

PPHV

VBUS

Figure 8-13. Internal Sink Path

8.3.3.2.1 Overvoltage Protection (OVP)

The application firmware enables the OVP and configures it based on the expected VBUS voltage. If the

voltage on VBUS surpasses the configured threshold VOVP4VSYS = VOVP4RCP/rOVP, then GATE_VSYS

is automatically disabled within tPPHV_FSD to protect the system. If the voltage on VBUS surpasses the

configured threshold VOVP4RCP, then GATE_VBUS is automatically disabled within tPPHV_OVP. When

VVBUS falls below VOVP4RCP - VOVP4RCPH, GATE_VBUS is automatically re-enabled within tPPHV_ON

because the OVP condition has cleared. This action allows two sinking power paths to be enabled

simultaneously and GATE_VBUS disables when necessary to ensure that VVBUS remains below VOVP4RCP.

While the TPS25751D is in BOOT mode in a dead-battery scenario (that is VIN_3V3 is low), it handles an

OVP condition slightly differently. As long as the OVP condition is present, GATE_VBUS and GATE_VSYS are

disabled. Once the OVP condition clears, both GATE_VBUS and GATE_VSYS are re-enabled. Because this is

a dead-battery condition, the TPS25751D draws approximately IVIN_3V3, ActSnk from VBUS during this time to

help discharge it.

TPS25751

SLVSH93 – OCTOBER 2023

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