2-2. Operation of overcurrent protection

In the event of a system failure, for example, when the load connected to the V_OUT pin is short-circuited to GND, the overcurrent protection function limits the output current to protect the load switch IC and the system in which it is used. When a drop in output voltage (V_OUT) causes excessive current to flow, Toshiba’s load switch ICs limit the output current to the set output limited current (I_CL) level by tripping a current limiting circuit. When V_OUT drops further, Toshiba’s load switch ICs perform current limiting 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 is zero, a short-circuit current (I_SC) continues flowing at the internally set level. The term “foldback” is derived from the shape of the output current (I_OUT)-vs-output voltage (V_OUT) curve that folds back during protection operation. When a faulty condition causing overcurrent disappears, the load switch IC automatically recovers from overcurrent protection, returning the output voltage to the normal level.