The dynamic input current limit makes sure that the voltage source is never overloaded. Before moving into how customers can avoid the overload, this module will look into how a battery behaves. Increasing the current delivered by the battery will translate into higher output power until the voltage at the terminals of the batteries starts to decline. Regardless of the output current demanded once this point has passed, the battery will be able to deliver only so much output power. When the voltage at the battery terminals is relatively low, if high load is demanded, the current surge that results at the battery is considerable. To support this output current, a drastic voltage drop at the terminals of the battery will take place, being drastically reduced to zero when the surge is big enough, which results in a battery short and therefore in an under voltage lockout of the converter that follows which would mean a system shutdown. If the high current demanded is only sporadic, the battery will recover the voltage level at the terminals. A way to avoid this on-off swing, which would continue until the high current demand disappears or the battery is fully discharged, would be to control the inrush current to avoid the voltage drop at the battery terminals. The TPS63020 can self control the inrush current when the voltage condition at the battery terminals falls below 2.3V. As mentioned before, passed a critical voltage at the terminals of the battery, increasing the current demanded to the battery will not translate in the output power required by the load. Under this battery voltage condition, if a large load is demanded, the TPS63020 reduces the current demanded from the battery, giving the battery time to maintain the output voltage. If the large load persists, the TPS63020 will discharge the battery and enter under voltage lockout smoothly, avoiding the on-off swing mentioned before. This works because the average inductor current is limited internally in the IC. At nominal operating conditions, the current limit is constant. If the input power source becomes weak, such as when batteries are almost discharged and they increase output impedance or there is an overload condition due to an additional heavy pulse load connected to the battery, the supply voltage at VIN may drop below 2.3V. If this occurs, the single inductor buck boost converter automatically reduces the current limit linearly, as it can be seen in this figure.