Other Parts Discussed in Thread: TPS2115A, TPS2115
I have a few questions about the TPS2113A and the TPS2115A.
My product requires me to switch between a local supply and a backup supply to keep an IC powered. Both rails are 3.3V. I also need it to switch back to the local rail when it recovers.
has an auto switch feature that will switch between the greater of the two inputs. From the datasheet it looks like it has a hysteresis of 0.1 to 0.2V on the comparator.
A) Does this mean that the TPS2115A cannot guarantee a switch back to the local rail after it recovers, since both will be at 3.3V?
B) is the hysteresis the value I should be looking at for the initial switch or is that the amount it needs to recover by in order to switch back?
This device has a VSNS pin that can make any rail the priority. However the truth table indicates that in the case where the VSNS is less than 0.8V then it depends on the Vin2 > Vin1 relationship.
A) In this case when I lose the rail on VSNS will the worst case switch over occur at 3.3V -200mV(hysteresis) ? This is a bit better as at least it will be able to switch back once Vsns is > 0.8V trip point but I still have an issue where it needs to drop 200mV.
What I would like to see happen is that it switches over automatically to INx when pwr drops below 3.2V on InY and go back to InY when it recovers....