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BQ25306: BQ25306EVM - Blinking intervals of the LED driven by the 'STAT' terminal

KC Nishio
Prodigy 10 points
Part Number: BQ25306

Greetings:

 

We have been evaluating evaluation boards of BQ25306 (BMS005 Rev. A). We realized that there are two frequencies of LED's blinking periods when the power was turn on with a 2-cell battery: 1) 1Hz,   2) About 0.5Hz

 

There is a description of the case 1) in the datasheet, which indicates "Vbus input over voltage," "TS cold/hot faults," Battery over voltage," "IC thermal shutdown," etc. However, there is no description about the case 2) in the datasheet.

 

Are there any technical documents that have descriptions of reasons about this blinking frequency range?

 

Thank you very much for your help in advance.

 

BR,

-kc

  • +1
    TI__Guru 52271 points

    Hi kc,

    Referring to Table 9-2. STAT Pin State on the d/s, the STAT pin blinks at 1Hz when some faults happen.

    When about 0.5Hz STAT blinking is observed, what are the charger operating conditions such as VBUS (voltage at VBUS pin), IVBUS, VBAT (voltage at BAT pin), IBAT, VSYS, ISYS?

    Thanks,

    Ning.

  • +1 in reply to Ning T
    Prodigy 10 points

    Hello Ning,

    Sorry for the delay to get back to you. Also, I thank you for your feedback.

    I started play with the eval. board of BQ25306 using a moderately charged battery, and I saw this fast-blinking LED behavior. The VBUS voltage was +12V, and the 10KOhm B3435 NTC of a battery was connected to the eval. board. Unfortunately, I did not have a chance to measure the current through the VBUS terminal and IBAT, etc., of the eval. board.

    Then I realized that by connecting the battery’s NTC line to the eval. board the IC enters to a hot fault condition. So, I removed 10KOhm R14 from the eval. board as the datasheet of the evaluation board stated. Since then, did not observe this symptom that is not described in the datasheet.

    Anyway, at this moment you do not need to investigate this behavior further, because this symptom won’t give any side-effects while our hardware is up & running.

    I appreciate your help on this.

    Kind regards,

    -kc Nishio

  • 0 in reply to KC Nishio
    Prodigy 10 points

    Just for your information:
    * To reproduce this 2Hz LED blinking, power on the eval. board without connecting a 2-cell battery with the setup for 1A charging current.
    * Interestingly connecting an external 10KOhm B3435 NTC to the EXT_TS terminal of the J1 connector, the LED started blinking in about 4Hz interval while applying 9V - 12V VBUS voltage.

    This issue is closed...