ZHCSGV1C June 2017 – March 2018 TPS25740B
PRODUCTION DATA.
The TPS25740B uses the VBUS pin to monitor for overvoltage or undervoltage conditions and implement the fast-OVP, slow-OVP and slow-UVP features.
If an over-voltage condition is sensed by the Fast OVP mechanism, GDNG is disabled within tFOVP + tFOVPDG, then a Hard Reset is transmitted and the VBUS discharge sequence is started. At power up the voltage trip point is set to V(FOVP) (5 V contract). When a contract is negotiated the trip point is set to the corresponding V(FOVP) value.
The devices employ another slow over-voltage protection mechanism as well that sends the Hard Reset before disabling the external NFET. It catches many OV events before the Fast OVP mechanism. During intentional positive voltage transitions, this mechanism is disabled (see Figure 1). However, tVP after the external NFET has been enabled, if the voltage on the VBUS pin exceeds V(SOVP) then a Hard Reset is transmitted to the Sink and the VBUS discharge sequence is started.
The devices employ a slow under-voltage protection mechanism as well that sends the Hard Reset before disabling GDNG. During intentional negative voltage transitions, this mechanism is disabled (see Figure 1). However, tVP after the external NFET has been enabled if the voltage on the VBUS pin falls below V(SUVP), then a Hard Reset is transmitted to the Sink and the VBUS discharge sequence is started.