Tool/software:
Dear Expert,
We want to control contactors with DDSG and DCHG pins and we also have predischarge functionality (predischarge contactor).
We configured DDSG and DCHG to mirror the state of the DSG and CHG pin so if there is a fault they are low (no contactor drive)
and when they high they enable the contactors.
The problem comes when the fault is cleared because since we have predischarge contactor the BQ enables PDSG contactor but at the same
time unfortunately it enables DDSG as well I think mistakenly because based on their functionalities the should be in opposite logic state all the time
(no main drive till predischarge finishes charging up the pack voltage). Also the TRM states the same:
I found another post that has the same problem:
My question is is there any possibility to update the firmware of the BQ76952 to correct this problem? I think it would be beneficial for many IC users.
Other possibilities could include:
(1) No solution but maybe you can tell me something: When we detect the fault the use DFETOFF to block DSG fet till PDSG is on. -> Problem: also PDSG is blocked
(2) We can put AND gates to DDSG and DCHG that are inverter ANDed with DPDSG bit so DDSG and DCHG is only enabled if PDSG is low again (finishes predischarge) -> Drawback: Raises hw complexity and requires new hw
Is there any other real options? I hope we can have some firmware update to solve this problem.
Please let me know and thanks,
Andras Magyar
