For two-channel systems with supplies that operate between 1.8V and 18V, Linear Technology offers the LTC4419 monolithic power prioritizer. The LTC4419 normally powers the load from the higher priority main supply such as a wall adapter or battery, switching to the backup supply—typically a secondary battery or large-value capacitor—during primary brownout or power loss conditions. As shown in the waveform, internal 2Ω 500mA current-limited switches multiplex from the 5V wall adapter to the two-cell Li-Ion battery when the V1 voltage falls below the adjustable switchover threshold, set here to 4V. By reducing device operating current to 3.6μA and the backup supply’s standby current drain to a low 0.32μA, the prioritizer extends run time in battery-powered systems. A freshness seal mode further lowers standby current to 0.12μA, minimizing backup battery discharge during product storage and shipment. Unlike other solutions, the LTC4419 does not require the backup supply voltage to be lower than the main supply voltage. Reversed battery voltages up to −15V are blocked from propagating to the load, and two auxiliary comparators with open-drain outputs provide flexible voltage monitoring.