BQ76952: Can BQ76952 identify disconnection faults?

Part Number: BQ76952

Tool/software:

If my AFE is not connected to the battery cell and the temperature NTC, at this time, if the overvoltage fault, undervoltage fault, overtemperature protection, and undertemperature protection are correctly configured and enabled, will the above faults be reported instead of correctly identifying the disconnection situation?

For example, if a battery cell is not connected, the undervoltage protection is triggered, but it cannot be recognized as a disconnection.

over 1 year ago

0 Thomas Rainey over 1 year ago

TI__Expert 4320 points

Hello,

There is no open wire detection bit or fault to monitor. You will only see COV and CUV faults trigger. This is explained in more detail in this E2E: https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1205904/bq76952-how-to-check-cells-is-disconnected-with-bq76952

Best regards,

Thomas Rainey

0 L over 1 year ago in reply to Thomas Rainey

Prodigy 220 points

So is it the same with temperature short circuit and disconnection?

0 Thomas Rainey over 1 year ago in reply to L

TI__Expert 4320 points

Hello,

The BQ76952 device includes an on-chip temperature measurement and can also support up to nine external thermistors on multifunction pins for temperature protections. For more information on temperature measurements you can refer to section 10.5 Internal Temperature Measurement and 10.6 Thermistor Temperature Measurement of the BQ76952 Technical Reference Manual (Rev. B)

Short circuit protection uses the voltage measurement across a sense resistor to determine if a short circuit has occurred. For more information on the short circuit protection you can refer to the 5.2.6 Short Circuit in Discharge Protection of the BQ76952 Technical Reference Manual (Rev. B)

Disconnection is as discussed above.

Best regards,

Thomas Rainey

0 L over 1 year ago in reply to Thomas Rainey

Prodigy 220 points

OK, thanks for your answer.
I think you misunderstood my question.
The question I raised was not about current short circuit, but about external NTC short circuit or disconnection (temperature sampling abnormality). Will the low temperature protection or high temperature protection be triggered by mistake at this time?

+1 Thomas Rainey over 1 year ago in reply to L

TI__Expert 4320 points

Hello,

Sorry for misunderstanding your question.

Since the thermistor is a NTC a short circuit could cause the overtemperature protection to trigger because the would mean ~0Ω resistance. Disconnecting the NTC thermistor would cause the ADC to read the REG18 voltage, this may cause a temperature protection to trigger.

Best regards,

Thomas Rainey

0 L over 1 year ago in reply to Thomas Rainey

Prodigy 220 points

Thanks, I understand.

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BQ76952: Can BQ76952 identify disconnection faults?