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BQ21061: At Low Power Mode, can Battery supply power to host system by PMID pin.

Daniel Chen95
Prodigy 60 points
Part Number: BQ21061
Other Parts Discussed in Thread: BQ21062

I will plan to design in BQ21061 as IOT device with chargeable battery. 

Because Battery quiescent current in Low-power is ~ 0.46uA, it's important parameter for us. Normally, this device keeps working by chargeable battery.

I have some questions as below. Kindly advise it, thanks.

1. BQ21061 is working at Low Power Mode, can Battery supply power to host system by PMID pin. 

2. In table 9-5, why don't  BATOCP function be enable without BATOCP function ?

3. in section 9.4.3 active battery, it describes the battery discharge FET is turned on connecting PMID to the battery. What is the difference of battery supply behaviors between Low Power Mode and Active Battery Mode?

Daniel

 

  • 0
    TI__Genius 12485 points

    Hi Daniel,

    I have replied with tag GR below- let us know if you have any questions. 

    1. BQ21061 is working at Low Power Mode, can Battery supply power to host system by PMID pin. 

    GR: Yes the transition from adapter to battery for powering PMID pin is automatic. So yes, the battery will supply the PMID in low power mode. 

    2. In table 9-5, why don't  BATOCP function be enable without BATOCP function ?

    GR: Can you clarify a bit more on this question? 

    3. in section 9.4.3 active battery, it describes the battery discharge FET is turned on connecting PMID to the battery. What is the difference of battery supply behaviors between Low Power Mode and Active Battery Mode?

    GR: The device has to be in Active mode if you plan to write any I2C transactions or change the LDO voltage etc., The system on PMID is supported by the battery regardless of Low Power Mode or Active Battery Mode. 

    Regards,

    Gautham

  • 0 in reply to Gautham
    Prodigy 60 points

    Hi Gautham,

    Thank you for  prompt support.

    Sorry for typo. Let me clarify Q2.

    2. In table Table 9-5. Function Availability Based on Primary Mode of Operation, why don't  BATOCP function be enable during low power mode ? It should protect battery because the system on PMID is supported by the battery.

    Except that, In section 9.3.2.4 Battery Short and Over Current Protection, It mentions that to protect the device from over current and prevent excessive battery discharge current, the BQ21062

    detects if the current on the battery FET exceeds IBAT_OCP.

    Daniel

  • 0 in reply to Daniel Chen95
    Prodigy 60 points

    Hi Gautham,

    Another question is about BQ21061-LDO output voltage configuration.

    What voltage is the default voltage of BQ21061-LDO supply?  If this LDO is configured as 3.0V output by I2C, is it reset to default voltage in low power mode or ship mode? What conditions can BQ21061-LDO reset to default output voltage? 

    Thanks.

    Daniel

    Daniel Chen95 said:

    Hi Gautham,

    Thank you for  prompt support.

    Sorry for typo. Let me clarify Q2.

    2. In table Table 9-5. Function Availability Based on Primary Mode of Operation, why don't  BATOCP function be enable during low power mode ? It should protect battery because the system on PMID is supported by the battery.

    Except that, In section 9.3.2.4 Battery Short and Over Current Protection, It mentions that to protect the device from over current and prevent excessive battery discharge current, the BQ21062

    detects if the current on the battery FET exceeds IBAT_OCP.

    Daniel

  • 0 in reply to Daniel Chen95
    TI__Mastermind 23410 points

    Hi Daniel,

    OCP is not available in low battery mode is that low power mode is the lowest quiescent current state where PMID is still active. This means that all other circuits outside of VDD, PMID, and /MR are turned off or in a low power state. This includes the OCP comparator that is used. This is enabled in the active battery mode.

     

    Daniel Chen95 said:
    What voltage is the default voltage of BQ21061-LDO supply?  If this LDO is configured as 3.0V output by I2C, is it reset to default voltage in low power mode or ship mode? What conditions can BQ21061-LDO reset to default output voltage? 

    By default, the BQ21061 is 1.8V. It will reset to this if the watchdog timer expires.