Current fold-back protection feature. If the temperature of the device rises to the thermal fold-back temperature threshold, the device will enter power-limiting mode. In this mode, the device thermally regulates the current through the switch in order to protect itself while still delivering as much current as possible to the output regardless of the current limit type selected. This helps to steadily charge a large capacitive load during startup.
The direct customer benefits of this approach is that there is no overheating of FETs, resulting in safer system operation. Also, this results in a much simpler design because there is no guesswork in sizing the FET to ensure it is in a safe operating area.
Foldback Current Limiting
A disadvantage of constant current limiting is that to obtain sufficient SOA the pass element must have a much higher collector current capability than is needed for normal operation. “Foldback” current limiting reduces the short circuit current while still allowing full output current during normal regulator operation, thereby giving more efficient use of the pass element's SOA.