• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 1762 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

bq27742-G1: Battery Management - Gas Gauge Forum

Denish Limbachiya
Intellectual 530 points
Part Number: BQ27742-G1

Hello Sir/Madam,

I have an issue with getting an output voltage of the fuel gauge.If I short once TP1 and TP2 as per attached schematic then only mosfet is initiate and fuel gauge give its output but if I o7446.SCHEMATIC1 _ PAGE1.pdfnce can't short this two test pad fuel gauge is not working.

So I want to know what happens in mosfet characteristic and What is the permanent solution for this thing if I don't want short once this two test pad according to attache schematic?

Kindly tell as if you require more information for the same.

Thanks & Regards,

Denish Limbachiya.

Embedded Hardware Engineer.

  • 0
    TI__Guru* 76230 points
    hello Denish,

    Inorder for the gauge to wake up from shutdown mode, a charger voltage has to be applied to packp pin to wake it up. So you shorting those two test points is essentially applying the battery voltage to packp pin. That is how the gauge is designed to operate to get it out of shutdown mode.

    i hope this helps.

    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Intellectual 530 points

    Hello OnyX,

    Thanks for your prompt reply it's really helpful for us.

    But there are two cases which happen with us during testing.

    1) First is if I test fuel gauge with Battery and USB, There will not require shorting this test pad and the fuel gauge is completely work proper.

    2) But if I test fuel gauge with the only battery so I need short once this two test pad so can you explain this incident in deeply because I have some confusion for the same.

    And can you suggest if there is a permanentnet solution if I don't want to short this test pad and if we can wake up fuel gauge from shut down mode?

    Thanks,

    Denish Limbachiya

  • 0 in reply to Denish Limbachiya
    TI__Guru* 76230 points
    Hello Denish,
    The gauge is designed to be powered on all the time once it has been woken from shutdown as long as the battery is attached. This is a pack side gauge and the battery is supposed to be attached all the time. So the waking from shut down mode is a one time effort.
    The reasoning for having the shutdown functionality is if for example your battery drains to empty and although your system gets turned off, the self discharge of the battery and the leakage of the boards components eg the gauge would cause the battery battery to drain further and get damaged. Hence the need for the device to enter shutdown to further prevent draining the battery. Now the device will wake from shut down once a charger voltage has been applied and the cell voltage is high enough to keep the device powered on.

    I hope this helps.

    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Intellectual 530 points

    Dear Onyx,

    Thanks for your inputs for the same.

    It is really helpful for us for understanding behavior of fuel gauge.

    Now there are no query for the same.

    Thanks,

    Denish Limbachiya