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BQ769142: BQ769142 wake up issue in sleep mode

Sherman Xin
Prodigy 350 points
Part Number: BQ769142

Hi Team,

Have a good day! My customer meets a technical issue about BQ769142. The project is 48V BMS in E-Bike.

When we set both MCU and BQ769142 in sleep mode, it happens that the BQ769142 will wake up several times in one minute, the power loss is about 600uA. You can see it in below figure. Could you help explain why and how to resolve it?

      

Many thanks!

BRs, Sherman

  • 0
    TI__Expert 8451 points

    Hi Sherman,

    For the BQ769142, the default sleep settings are not recommended, as they can cause the issue you are observing now.  Please see table 7.2 in the TRM (BQ769142 Technical Reference Manual (Rev. C) (ti.com)) to see the recommended settings. 

    Best,

    Andria

  • 0 in reply to Andria McIntyre
    TI__Prodigy 350 points

    Hi Andria,

    They always set the recommended option as below, are there any other possibility? Thank!

    BRs, Sherman

  • 0 in reply to Sherman Xin
    TI__Expert 8451 points

    Hi Sherman,

    SLEEP mode is designed to reduce current consumption, but it also allows the device to perform measurements, calculations, and data updates in adjustable time intervals, with battery protections still enabled.  Seeing the device "waking up" to take these measurements in the specified intervals is simply a feature of SLEEP mode.

    If you would like to configure how the device operates in SLEEP mode, you can change how often the device wakes to measure voltages and temperatures while in SLEEP mode.  Please refer to 13.4.2.2 Power:Sleep:Voltage Time in the TRM for more information.  The default voltage time value is 5 seconds.

    If you have concerns about current levels in sleep mode, section 13.4.2 Power:Sleep in the TRM includes more information about the measurements you are seeing.  Even NORMAL mode has a power mode of 286 µA.  The power mode indicates the average value for its respective mode.

    Best,

    Andria