2-2. Overcurrent protection operation of LDO regulators

When a short-circuit between a load on the V_OUT side and GND or other system failure occurs, this function limits the output current of an LDO regulator to protect itself and the system in which it is used. Toshiba’s LDO regulators provide overcurrent protection called foldback. In the event of excessive current higher than the internal threshold, foldback reduces the output current (I_OUT) as the output voltage (V_OUT) decreases. Even when the output voltage has reached 0 V, the output current continues flowing at the internally set level. The term “foldback” is derived from the shape of the I_OUT-vs-V_OUT curve that folds back as shown below during protection operation. When a faulty condition causing an overcurrent condition disappears, an LDO regulator automatically recovers from overcurrent protection, returning the output voltage to the normal level.