I'm working on a product that will run off of either a solar/battery input or a power supply. I would like to make the circuit boards all the same, and they will include a built in MP1584 buck converter as a voltage regulator. The issue is that when hooked up to solar the input voltage is high enough the regulator operates fine but when hooked up to the power supply at ~6.2v, the input voltage drops to under 5v after it passes through the converter which isn't enough to even power up the Atmega328. The regulator's only purpose is as a charge controller for the battery. There is an on-board 5V linear regulator for the board electronics.
I'm trying to come up with a way to design a automatic switch, either using analog components or an IC that will detect the input voltage and if it is lower than 7V, bypass the buck converter and go straight to the circuit board/battery. If higher than 7V, pass through the converter.
I'm looking for a solution that is going to be relatively simple and very inexpensive, >$1 per board on a 500 unit order. The simple, cheap, and failsafe workaround would be to put a DIP switch on the board that manually selects the solar or AC input before they ship. If there was a cleaner solution though, I would like to find it. My knowledge base is not deep within EE so I don't know if perhaps there are some basic ICs or components that I'm not aware of that would make this a simple design.
I'm trying to come up with a way to design a automatic switch, either using analog components or an IC that will detect the input voltage and if it is lower than 7V, bypass the buck converter and go straight to the circuit board/battery. If higher than 7V, pass through the converter.
I'm looking for a solution that is going to be relatively simple and very inexpensive, >$1 per board on a 500 unit order. The simple, cheap, and failsafe workaround would be to put a DIP switch on the board that manually selects the solar or AC input before they ship. If there was a cleaner solution though, I would like to find it. My knowledge base is not deep within EE so I don't know if perhaps there are some basic ICs or components that I'm not aware of that would make this a simple design.