Hello,
I have a circuit that works off of 3V. I get the 3V in two different ways, one is through a 9V battery that plugs into a DC power barrel receptacle that goes to a 3V regulator, and the other is from a 3V pin that is available on the circuit. I'm wondering if there is a way the circuit could automatically use the 3V pin if there's no battery plugged into the DC barrel receptacle, and if there is a battery plugged in it would switch and use the 3V coming out of the 3V regulator.
At first I was thinking about OR'ing the power sources through some diodes... but since I'm working with 3V, I really don't want to give up a diode voltage drop on my power. Next I started looking at the DC barrel receptacles that have built in switches (I've never used these before) and seems like this would be a good option if I was working with the same voltages, but since one of my voltage is 9V and the other is 3V, I need the 3V pin to bypass the voltage regulator, and the 9V to go to the voltage regulator... so they are going to different places on my circuit (different sides of the regulator essentially).
any suggestions would be appreciated, much thanks!