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PF status SOTD, SOTC, AFE_C........ bq20z75 V.1.60

Kjell Ramberg
Expert 1375 points

Anybody having an opinion of the following issue are welcome to comment.......

Recently we have experienced for some of our batteries that the PF flag SOTD and SOTC been set and the temperature have been reported to around 125 deg C. For some batteries we have also noticed that PF status AFE_C been set. AFE Fail limit parameter is set to 20. SOT Chg is set to +65deg C and SOT Dsg is set to +80 deg C. 

We have an extra temperature indicator (temp strip) added to the battery showing no temperature increase above ambient. We are sure that the very high temperature indicated is not correct.

The battery is supplying a transmitter drawing high current pulses and we are thinking that the PF status bit being set is caused by interference. If so - we had expected that the temperature might be set to totally different values from time to time - not centered around 125 deg C. Is there a reason why it seems like the reported temperature is around 125 deg C when interference is causin a PF? 

As a part of the diagnose - I wondered if monitoring ResetData (0x57) and WDResetData (0x58) could give info of how "bad" the current spikes interfere with the Data flash/RAM and that the results could give a pointer if there would be any help increasing the AFE Fail limit above 20. For a normal application with no noise etc - what  is regarded as OK values for ResetData - or is this a silly question ?

When the ResetData reach Max value will it then start all over again ?

Any help will be very much appreciated

Regards

Kjell

  • 0
    TI__Guru* 76230 points
    hi Kjell,
    the reset data will give an indication of how many resets occurred on the chip. it is possible that the interference could have cause the temperature to read a wrong value , but that interference might have not cause a reset to occur so that might not be a good indication on how bad the spikes are. You might also want to check the solder joint connection of your thermistor to ensure that it isn't having partial contact. Also try shielding your communication lines before running a test to see if this problem happens again

    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Expert 1375 points

    Hi Onyx

    Thank for valuable info. I will follow Your advice and also check the solder joint Connection to the thermistor.

    Best regards

    Kjell