My bq77910A design has CHGST high, the bq77910A wakes up during cell connection and has set the open cell fault before I get all cells connected. How can I prevent this and recover from it?
How can I reset the bq77910A?
One solution to the open cell fault during connection would be to hold the CHGST signal low until after cells are connected. The part would then not wake up during connection but would wake up in a normal condition at a later assembly/test step. If the system does not allow this, reset the part to bring it back to a pre-wake condition.
The bq77910A does not have a reset pin, but its power on reset function is tied to the VREG output and can be triggered by inducing a voltage at VREG below the VPOR level indicated in the datasheet. One possible way may be to apply a DC load just less than the absolute maximum VREG current. Another way would be to switch a capacitive load onto VREG to quickly discharge the output capacitor while avoiding a high DC current.
CRESET might be approximately the same size or smaller than CVREG, Rp is large to provide minimal load on the regulator but to discharge CRESET after the event, Rs ~0 or small to limit the instantaneous capacitor currents.
When CHGST is held high during reset, the regulator remains on and the device will wake up again. When CHGST is low during reset, the device will shut down.
