During discontinuous conduction mode, the load current is lower than half of the peak-to-peak inductor current ripple and the switching frequency decreases when the load is further decreased in pulse skipping mode. A switching pulse is set when V_FB drops below 1.2 V.

As the frequency of operation decreases and V_FB remains above 1.2 V (V_REF) with the output capacitor sourcing the load current for greater than 15 µs, the converter enters an ultra-low I_Q sleep mode to prevent draining the input power supply. The input quiescent current (I_Q) required by the LM5013-Q1 decreases to 10 µA in sleep mode, improving the light-load efficiency of the regulator. In this mode, all internal controller circuits are turned off to ensure very low current consumption by the device. Such low I_Q renders the LM5013-Q1 as the best option to extend operating lifetime for off-battery applications. The FB comparator and internal bias rail are active to detect when the FB voltage drops below the internal reference, V_REF, and the converter transitions out of sleep mode into active mode. There is a 9-µs wake-up delay from sleep to active states.