7.3.2 Dynamic Current Limit

To protect the device and the application, the average inductor current is limited internally on the IC. At nominal operating conditions, this current limit is constant. The current limit value can be found in the electrical characteristics table. If the supply voltage at VIN drops below 2.3 V, the current limit is reduced. This can happen when the input power source becomes weak. Increasing output impedance, when the batteries are almost discharged, or an additional heavy pulse load is connected to the battery, can cause the VIN voltage to drop. The dynamic current limit has its lowest value when reaching the minimum recommended supply voltage at VIN. At this voltage, the device is forced into burst mode operation, trying to stay active as long as possible even with a weak input power source.

If the die temperature increases above the recommended maximum temperature, the dynamic current limit becomes active. Similar to the behavior when the input voltage at VIN drops, the current limit is reduced with temperature increasing.