DC2160A: 1.7 ~ 18V in, 2 Ch Power Prioritizer

Demonstration circuit 2160A uses the LTC4419 to provide backup switchover, keeping the output load powered during brown out or power loss conditions. Priority is assigned by supply connection to the V1 and V2 inputs. The power source connected to V1 has a higher priority and is monitored by undervoltage switchover threshold comparator. If V1 exceeds 1.55V and ADJ is above 1.097V for 64ms, V1 is considered valid, and the LTC4419 connects V1 to the load. If V1 drops below 1.52V, or ADJ drops below 1.047V, V1 is considered invalid, and the LTC4419 powers the load from V2. The upper limit for V1 is the maximum operating voltage, 18V; however, the recommended V1 voltage is 12V. Practically, any voltage from the operating range can be selected for V2.

The LTC®4419 is a dual input monolithic prioritizer with low operating current, which provides backup switchover for keeping critical circuitry alive during brown out and power loss conditions. Unlike diode-OR products, little current is drawn from the inactive supply even if its voltage is greater than the active supply. Internal 2Ω, current limited PMOS switches provide power path selection from a primary input (V1) or a backup input (V2) to the output. An adjustable voltage monitor set via an external resistive divider provides flexibility in setting the V1 to V2 switchover threshold. When primary input V1 drops, the ADJ monitor input causes OUT to be switched to V2. Fast non-overlap switchover circuitry prevents both reverse and cross conduction while minimizing output droops. The LTC4419 has two auxiliary comparators with open drain outputs that provide flexible voltage monitoring. The V2ON output indicates if V2 is powering OUT. Freshness seal mode prevents V2 battery discharge during storage or shipment.