Hello,
I have a few questions regarding the TPS54821 that we’re considering using in a high-current battery charger circuit. Questions are in bold.
1. The output of the TPS54821 will be connected to a large battery.
a. When input power is removed, will there be a reverse leakage path through the TPS54821? If so, what would be the impedance of the leakage path? Any potential for a latchup condition to occur here
2. With regard to the error amplifier, we spec the COMP to Iswitch gm as 21 A/V.
b. 
a. Would it be possible to get min/max values for this?
3. The TPS54821 has a voltage offset on the COMP pin. It looks like it is one diode drop but could also be derived from the temp compensated 0.6V reference. I’m guessing the offset is so the rest of the circuits can be built without a negative power supply rail.
a. Is the COMP pin offset from ground is in fact one diode drop or is it derived from a temperature compensated source?
b. We tried to measure the temp coefficient; however, it looks like the value is substantially less than a diode drop but more than what we would expect if the signal is derived from the stable reference.
c. If the offset is derived from a simple diode drop, would you be able to tell us if the power stage has a similar offset built in which tracks with temp?
i. We’re asking because we need to know the slope to build into the temp comp for an external active clamp. The goal is to have relatively stable current limits over temperature after an initial adjustment at room temp in manufacturing.
Many thanks in advance for your help.
