The switch current limit prevents the devices from high inductor current and from drawing excessive current from the battery or input voltage rail. Excessive current might occur with a shorted/saturated inductor or a heavy load/shorted output circuit condition. If the inductor current reaches the threshold I_LIMF, the high-side MOSFET is turned off and the low-side MOSFET is turned on to ramp down the inductor current. Once this switch current limit is triggered 32 times, the devices stop switching and enable the output discharge. The devices then automatically start a new start-up after a typical delay time of 100 µs has passed. This is HICCUP short circuit protection and is implemented to reduce the current drawn during a short circuit condition. The devices repeat this mode until the high load condition disappears.

When the device is in forced PWM mode, the negative current limit of the low-side MOSFET is active. The negative current limit prevents excessive current from flowing back through the inductor to the input.