This reference design includes a complete power management solution for a standalone emergency call (eCall) system in an automotive environment. The circuit is supplied directly from the car battery rail. It also manages a backup battery to power the eCall system while the car battery rail is not available. It includes power path management which routes the available power rail directly to four DC/DC converters which are supplying the required functional blocks of the eCall system. The solution is optimized to operate at maximum efficiency while powered from the backup battery.