The TPS92515 can operate safely even when the input voltage enters the drop-out region. As VIN approaches VLED, ΔIL-PP falls to a level much lower than during normal operation. Because the average output current is based on Equation 10, as ΔIL-PP becomes smaller, the average current tends to increase. The amount of increase depends on the value of ΔIL-PP used in the design. If drop-out performance is a concern, performance can be improved by lowering the ΔIL-PP design parameter.