Hello,
I am having a few issues with one of my designs. I have a two separate Lithium ion batteries connected to a power mux(TPS2115APW ). There are a few other blocks before this(battery charger, health monitor, reverse polarity, push button controller), but this section of the circuit is where I am having problems. The output of the mux goes to a 5V DC-DC (TPS61200). The circuit works fine down to a battery voltage of about 3.3V at which case there seems to be a 1V drop across the mux. With this drop the input voltage of the DC-DC is 2.09V, and the regulator cannot successfully regulate at 5V(It drops to 4.09V). At battery voltages higher than 3.3V, the drop across the mux is negligible. Attached is a block diagram with the measure voltages at the different stages of the circuit:
Please let me know if you need more information or if you have anything you would like me to try.
Thanks,
Felipe Ocampo