The switch current limit prevents the device from high inductor current and from drawing excessive current from the battery or input voltage rail. Excessive current can occur with a shorted or saturated inductor or a heavy load or shorted output circuit condition. If the inductor current reaches the threshold I_LIM, the high-side MOSFET is turned off and the low-side MOSFET remains off, while the inductor current flows through the body diode and quickly ramps down.

When this switch current limits is triggered 32 times, the device stops switching. The device then automatically starts a new start-up after a typical delay time of 128 µs has passed. This is named HICCUP short-circuit protection. The device repeats this mode until the high load condition disappears.

In forced PWM devices, a negative current limit (ILIMN) is enabled to prevent excessive current flowing backwards to the input. When the inductor current reaches ILIMN, the low-side MOSFET turns off and the highside MOSFET turns on and kept on until TON time expires.