TPS54625 detects over and under voltage conditions by monitoring the feedback voltage (VFB). This function is enabled after approximately 1.7 x times the softstart time.

When the feedback voltage becomes higher than 125% of the target voltage, the OVP comparator output goes high and the circuit latches and both the high-side MOSFET driver and the low-side MOSFET driver turn off.

When the feedback voltage becomes lower than 65% of the target voltage, the UVP comparator output goes high and an internal UVP delay counter begins. After 250us, the device latches off both internal top and bottom MOSFET.