How does overcurrent protection work in an LDO regulator?

In the event of an overcurrent condition, our LDO regulators are protected by foldback.

The term “foldback” is derived from the shape of the output current (I_OUT)-vs-output voltage (V_OUT) curve that folds back as shown in Figure 1 during protection operation.

Under a short-circuited load condition, foldback reduces I_OUT as V_OUT decreases. When V_OUT has dropped to zero, it keeps the output current at a limited constant level.

When the overcurrent condition has disappeared, V_OUT returns to the normal level automatically.

If an output capacitor or a capacitive load is connected to the output pin, V_OUT increases while I_OUT is limited by foldback.