Analog Devices LTC4419 | Demoboard DC2160A

Description

Demonstration circuit 2160A uses the LTC®4419 toprovide backup switchover, keeping the output loadpowered during brown out or power loss conditions.Priority is assigned by supply connection to the V1 andV2 inputs. The power source connected to V1 has a higherpriority and is monitored by undervoltage switchoverthreshold comparator CADJ (pin ADJ). If V1 exceeds1.55VandADJ is above 1.097Vfor 64ms, V1 is consideredvalid, and the LTC4419 connects V1 to the load. If V1drops below 1.52V, or ADJ drops below 1.047V, V1 isconsidered invalid, and the LTC4419 powers the loadfromV2. TheDC2160A is populated to provide switchoverwhen V1 drops below 10.19V ±0.33V. The upper limit forV1 is the maximum operating voltage, 18V; however, therecommendedV1 voltage is 12V. The resistivedivider (R1-R2) of the first auxiliary comparator CMP1 is adjusted totrigger the comparator when VCMP1_TOP’s voltage is inthe 9.92V to 10.74V range. Practically, any voltage fromthe operating range can be selected for V2, however, 5Vis recommended to have a standard voltage level. L, LT, LTC, LTM, Linear Technology, and the Linear logo are registered trademarks andPowerPath is a trademark of Linear Technology Corporation. All other trademarks are theproperty of their respective owners.PERFORMANCE SUMMARYThe second auxiliary comparator CMP2 divider (R8-R7) isadjusted to trigger the comparator when VCMP2_TOP’svoltage is in the 3.26V to 3.53V range. Overcurrent (0.5Ato 1.6A) and thermal protection inherent to the LTC4419allows safe prioritization. Overtemperature protection isactivated when the junction temperature exceeds 125ºC.Another inherent feature – reverse supply protection –protects the prioritizer and load when a negative voltage(up to –15V) is applied to any input – V1 or V2.The LTC4419’s “break-before-make” switching methodprevents cross conduction between input channels. TheLTC4419 does not connect any input source to the loaduntil the input voltage exceeds the output by 50mV. Thiseliminates reverse currentfromtheoutputintothe selectedinput supply.

Features

Demonstration circuit 2160A uses the LTC®4419 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 CADJ (pin ADJ). 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 DC2160A is populated to provide switchover when V1 drops below 10.19V ±0.33V. The upper limit for V1 is the maximum operating voltage, 18V; however, the recommended V1 voltage is 12V. The resistive divider (R1-R2) of the first auxiliary comparator CMP1 is adjusted to trigger the comparator when VCMP1_TOP’s voltage is in the 9.92V to 10.74V range. Practically, any voltage from the operating range can be selected for V2, however, 5V is recommended to have a standard voltage level.

More information

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