ASA to ALL
i am working on a car security circuit .... my ciruit works on 5volt i need internal battry backup in case some one cut car battery ....... anyone here want to share battery backup and its charging circuit, idea or any web link pls share.
You can use LTC4412 IC from linear tech. for ORing internal bat with external battery
if power consumption is important - if it is not important you can use 2 diode..