The TPS62148 is protected against overload and short circuit events. If the inductor current exceeds the current limit I(LIMF), the high side switch is turned off and the low side switch is turned on to ramp down the inductor current. This allows it to provide the maximum current, for example, charging a large output capacitance without the must increase the soft-start time.

Due to internal propagation delay, the actual current can exceed the static current limit during that time. The dynamic current limit is given as:

Equation 8.

where

• I_LIMF is the static current limit as specified in the electrical characteristics
• L is the effective inductance at the peak current
• V_L is the voltage across the inductor (V_IN - V_OUT) and
• t_PD is the internal propagation delay of typically 50 ns.

The current limit can exceed static values, especially if the input voltage is high and very small inductances are used. The dynamic high side switch peak current can be calculated as follows:

Equation 9.