The TPS6281x-Q1 is protected against overload and short circuit events. If the inductor current exceeds the current limit I_LIMH, the high-side switch is turned off and the low-side switch is turned on to ramp down the inductor current. The high-side switch turns on again only if the current in the low-side switch has decreased below the low-side current limit. Due to internal propagation delay, the actual current can exceed the static current limit. The dynamic current limit is given as:

Equation 4.

where

• I_LIMH 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)
• 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 5.