The TPS53318 and TPS53319 devices monitor the resistor divided feedback voltage to detect overvoltage and undervoltage. 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 counting. After 1 ms, the device latches OFF both high-side and low-side MOSFETs drivers. The controller restarts after a hiccup delay (refer to Table 8-2). This function is enabled 1.5-ms after the soft start is completed.

When the feedback voltage becomes higher than 120% of the target voltage, the OVP comparator output goes high and the circuit latches OFF the high-side MOSFET driver and latches ON the low-side MOSFET driver. The output voltage decreases. Before the latch-off action for both the high-side and low-side drivers, the output voltage must be pulled down below the UVP threshold voltage for a period of 1 ms. After the 1 ms period, the drivers are latched off.