Tool/software:
Hi Team,
We are using the BQ76905 IC for battery voltage monitoring and protection applications. We are able to successfully read and write all data to/from the IC using an STM32 controller.
However, when our device enters short circuit protection (SCD), we are unable to detect the load removal from the system. Specifically, when a load is connected, the CDRAW bit in the Alarm Raw Status register returns 1, and when the load is removed, the CDRAW bit returns 0. Please correct me if I am wrong in this understanding.
When we place a 10kΩ resistor between PACK- (Pack Negative) and GND, the CDRAW bit functions correctly. But when the resistor is removed, the CDRAW bit takes a long time (from 1 minute to 5 minutes) to change its state.
The short circuit detection (SCD) is working as expected — it triggers after two retries and then latches into a fault state as per our configuration. Our FETs are set to autonomous mode.
In the reference design, there is no resistor between PACK- and GND, and the CDRAW pin functions correctly. Therefore, we would like to understand why it seems necessary to add a resistor in our case for the CDRAW bit to reflect the correct status. Additionally, we would like to know how to recover from the SCD fault in this autonomous configuration.