Many systems require a backup battery to provide power in the event of a power outage.  Switching between the main power and the backup battery power without incurring significant efficiency degradation or cost is a tricky challenge.   This design provides a high accuracy, low current solution for systems using a 12 V rail with a backup battery at a lower cost than existing devices.
          Features
          
          - Low current consumption in battery backup mode: 28 uA
 - High voltage threshold accuracy: 1.75% including resistors
 - Independent voltage programming on primary and secondary rails