Tool/software:
We have a problem with the BQ25606 charger when there are no batteries in the system. When we turn on either 1 of 2 downstream regulators (TPS552892RYQ), the SYS output of the battery charger drops to the point where either the system won't power on or the system power turns off due to low voltage. This has been observed to happen only when the battery charger is idle (not actively in a charge cycle) or when charging has been disabled. This feels like a control loop issue when not in a charging state.
If this can't be resolved, then my plan will be to design in a bypass switch between the 5VIn and the SYS output so the device can operate normally without batteries installed. The only way I've made it work so far is to hang seriously large capacitors off SYS or BATT which is both probably not recommended and not feasible in the design.
Ideally the downstream regulator(s) would have a configurable soft start to prevent this, but I can't find anything (TI or otherwise) that has that and will work for my application.
Any help would be appreciated.
Battery Charger Schematic snippet:
VSYS (top), 5V Input (bot) - system turned off when downstream regulator enabled:
VSYS (top), V Regulator (bot) - system stayed on when downstream regulator enabled:
VSYS (top), V Regulator (bot) - system turned off when downstream regulator enabled:
