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BQ27421-G1: Don't enter into Hibernation mode and question

Katsu Matsunaga
Expert 7730 points
Part Number: BQ27421-G1
Other Parts Discussed in Thread: EV2400, BQSTUDIO

Hello expert,

I would like to confirm a program of hibernation mode. 

Below configuration has been programed, but measurement value of current had not changed even if device was in hibernation condition. It seems that the device didn't enter to Hibernation mode.

Does any other configuration need?

Could you please give any advice us?

[Configuration]
Hibernate I：3mA
Hibernate V：4000mV
CONTROL_STATUS [HIBERNATE]=1

[test condition]
Battery voltage = 3.8V
Load current= less than 150uA

One more question:

What kind of problem does user have if  BQ27421YZFR-G1B uses for 4.2V max charge voltage instead of -G1A?

Because, customer's previous project uses -G1B, so they would like to use the same part for new project.

Best regards,

Katsu

  • 0
    TI__Genius 11535 points

    Hello Katsu,

    The fuel gauge waits to enter Hibernate mode until it has taken a valid OCV measurement and the magnitude of the average cell current and cell voltage has fallen below Hibernate Current and Hibernate Voltage, respectively. In order for this to happen, make sure the Impedance Track is enabled. Also, make sure the dashboard on bqStudio is disabled if you have the EV2400 plugged in for I2C communications to work. This is described in Section 2.4.6 of the TRM. 

    The only difference between the BQ27421YZFR-G1B and -G1A is the battery type and chemID. The maximum charge for the -G1B is 4.3-4.35V while the max charge for the -G1A is 4.2V so there shouldn't be any problem.

  • 0 in reply to Jessica H.
    TI__Expert 7730 points

    Hi Jessica-san,

    Thank you for your response.

    Could you please tell me how to confirm the enabling the impedance track and set enable?

    Best regards,

    Katsu

  • 0 in reply to Katsu Matsunaga
    TI__Genius 11535 points

    Hello Katsu-san,

    For this device, Impedance Track is always enabled.

    Also, it looks like the link in my previous post is broken. Here is the link to the TRM: www.ti.com/.../sluuac5c.pdf

  • 0 in reply to Jessica H.
    TI__Expert 7730 points

    Hi Jessica-san,

    from the TRM, my understanding is that below configuration is enough for setting of Hibernate mode.

    Hibernate I：3mA
    Hibernate V：4000mV
    CONTROL_STATUS [HIBERNATE]=1

    However, my customer can not see the current of datasheet spec.  Please give any advise.

    Thanks and best regards,

    Katsu

  • 0 in reply to Katsu Matsunaga
    TI__Mastermind 24870 points

    Hello Katsu-san,

    Please make sure you have allowed the gauge to take an OCV reading.

    Thanks!

  • 0 in reply to Kang Kang
    TI__Expert 7730 points

    Hi

    Could you tell me how to confirm the taking of OCV reading?

    Customer has checked a flag of "OCVTAKEN", but it stay in HIGH "1".

    In this case, can device enter in hibernate mode?

    Or do we need to get the flag transient from 0 to 1, for enter into hibernate.

    My customer cannot observe different current between sleep and entering hibernate mode. Is measuring current only way to see these mode?

    Best regards,

    Katsu 

  • 0 in reply to Katsu Matsunaga
    TI__Mastermind 24870 points

    Hello Katsu-san,

    1. OCV is taken on the bq27421 when dv/dt condition satisified.

    2. Yes the device will enter hibernate if you have taken an OCV and still satisfy the conditions listed in the TRM.

    3. Make sure to remove communication to the device.