The TPS54325-Q1 monitors a resistor divided feedback voltage to detect overvoltage and undervoltage. When the feedback voltage becomes higher than 120% of the target voltage, the OVP comparator output goes high and the circuit latches the high-side MOSFET driver turns off and the low-side MOSFET turns on.

When the feedback voltage becomes lower than 70% of the target voltage, the UVP comparator output goes high and an internal UVP delay counter begins. After 250 μs, the device latches off both internal top and bottom MOSFET. This function is enabled approximately 1.7 × soft-start time.