The LMR16030 operates in sleep mode at light load currents to improve efficiency by reducing switching and gate drive losses. If the output voltage is within regulation and the peak switch current at the end of any switching cycle is below the current threshold of 300 mA, the device enters sleep mode. The sleep mode current threshold is the peak switch current level corresponding to a nominal internal COMP voltage of 400 mV.

When in sleep mode, the internal COMP voltage is clamped at 400 mV, the high-side MOSFET is inhibited, and the device draws only 40-μA (typical) input quiescent current. Since the device is not switching, the output voltage begins to decay. The voltage control loop responds to the falling output voltage by increasing the internal COMP voltage. The high-side MOSFET is enabled and switching resumes when the error amplifier lifts internal COMP voltage above 400 mV. The output voltage recovers to the regulated value, and internal COMP voltage eventually falls below the sleep mode threshold, at which time the device again enters sleep mode.