SLVSDV8 July 2017 TPS54424
The TPS54424 incorporates an output overvoltage protection (OVP) circuit to minimize output voltage overshoot. The OVP feature minimizes the overshoot by comparing the FB pin voltage to the OVP threshold. The OVP threshold is the same as the 108% PGOOD threshold. If the FB pin voltage is greater than the OVP threshold the high-side MOSFET is turned off preventing current from flowing to the output and minimizing output overshoot. When the high-side MOSFET turns off, the low-side MOSFET turns on and the current in the inductor discharges. The output voltage can overshoot the OVP threshold as the current in the inductor discharges to 0 A. When the FB voltage drops lower than the 106% PGOOD threshold, the high-side MOSFET is allowed to turn on at the next clock cycle.