Bellow circuit is an uninterrupted power supply(4.7 Vout after regulator) with auto shutdown when the battery is low. I am using a 6-volt lead acid battery with 9v charger.
I am looking for an Idea to help me to avoid D4 because I would like to shut down the system when the battery is 5v and not 5.7v. since I can not find a regulator that can provide 4.7 when the input voltage is less than 5V.
if you think this is not good design, I will appreciate you provide a better way.
(The LEd symbol is meant to be a pump (150ma max))