During normal operation, the high-side and low-side MOSFET switches are protected by the current limit I_LIMF. When the high-side MOSFET switch reaches the current limit, it turns off and the low-side MOSFET switch turns on. The high-side MOSFET switch can only turn on again when the current in the low-side MOSFET switch decreases below I_LIMF. The device is capable of providing peak-inductor currents up to the internal current limit,_ILIMF..

As soon as the switch current limits are met and the output voltage falls below 1/3 of the nominal output voltage because of overload or short circuit condition, the foldback current limit is enabled. In this case, the switch current-limit is reduced to 1/3 of the nominal value I_LIMF.

Because the short-circuit protection is enabled during start-up, the device does not deliver more than 1/3 of the nominal current limit, I_LIMF, until the output voltage exceeds 1/3 of the nominal output voltage. This protection must be considered when a load is connected to the output of the converter, which acts as a current sink.