Tool/software:
Dear TI Support Team,
I am currently conducting functional validation of the BQ76952 protection features, specifically focusing on the Over-Temperature during Charge (OTC) protection behavior.
Based on the [Technical Reference Manual], the OTC protection is designed to trigger an alert when the cell temperature reaches or exceeds the programmable TOTC threshold. After a delay (OTC_DLY), it is expected to raise a fault and, if autonomous FET control is enabled, turn off the CHG FET accordingly.
However, during testing, I observed the following:
Regardless of whether the battery is idle, discharging, or charging, as long as the cell temperature exceeds the configured OTC threshold, the device triggers the OTC protection (first alert, then fault after delay).
This behavior led to my confusion, as I initially understood that OTC would only be active and considered valid when the battery is under a charging condition (i.e., charging current present), and similarly, OTD protection would only be relevant during discharging.
My key questions are:
- Is this observed behavior expected and correct — that OTC can trigger even when the battery is not in a charging state (e.g., idle or discharging)?
- Does the BQ76952 internally check the battery current direction/state (i.e., charge vs discharge) when determining whether to apply OTC or OTD protections?
- Or are the OTC and OTD protections purely based on temperature thresholds, and independently trigger faults regardless of actual system operation state?
In our current configuration:
- TOTC is set to 40°C
- OTC_DLY is set to 2 seconds
- Recovery is configured at 35°C
Additionally, we ensured that CHG FET protection is enabled for OTC in Settings:Protection:CHG FET Protections B[OTC].
I would appreciate it if you could confirm whether the protection logic as currently implemented is operating as intended, and clarify whether current flow direction plays any role in the OTC/OTD evaluation.
Thank you in advance for your support.
Best regards,
DRALUU
