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Li-Ion Battery management with TPS65070

kartik gandhi
Prodigy 250 points
Other Parts Discussed in Thread: AM1808, TPS65070, BQ27200

Dear Experts,

We are using AM1808 which consists TPS65070 as power management in our custom design.  We have provided USB supply as input to TPS65070 and connected Li-Ion battery pack to it.  There is an I2C interface between AM1808. 

How can I know that my battery is getting charged when USB source connected but AM1808 is in deep sleep mode?  Is there any way to know charging status using TPS6570.  Please note that we are using BQ27200 as a battery monitor but since AM1808 is in deep sleep mode we are not able to communicate with BQ27200.

Your prompt reply will be appreciated here.

Regards,

Kartik Gandhi

  • 0
    TI__Intellectual 880 points

    Kartik Gandhi,

                             Please send the schematics of your custom design board.

    --- Abhijit

  • 0
    Expert 1950 points

    Hello,

    If you only want to know if battery is charging for debugging purposes, the most direct way is to measure the voltage on the shunt resistor (typ. 20 milli-ohms) used by the BQ27200 to monitor current battery.

    Regards

  • 0 in reply to Jakez
    Prodigy 250 points

    Hello Jakez,

    I could not read BQ27200 since my AM1808 is in deep sleep mode.   Is it possible that we can access BQ's register using AM1808's I2C lines while am1808 is in deep sleep mode?

    Basically, I want to provide an LED indication using GPIO by reading BQ's registers about battery's charging status an all while AM1808 is in deep sleep mode.

    Regards,

    Kartik Gandhi

  • 0 in reply to kartik gandhi
    Expert 1950 points

    Hello again,

    Ok, some misunderstanding, it's not for debugging, forget the multimeter.

    The battery charge is controlled by the TPS65070, which is not able to output its charging state by itself, nor even generate interrupts about it.

    While in deep sleep mode, the AM1808 is of course totally inactive (no clocks) and unable to wake-up by itself if DEEPSLEEP is externally controlled.

    My suggestions for a simple LED charging indication without additional hardware are (external DEEPSLEEP assumed in your application):

    - Connect external DEEPSLEEP request to a GPIO interrupt, and use periodic wake-up by the RTC (1 s) for refreshing the charging status and check for external DEEPSLEEP request exit.

    Inconvenients: few ms of processing each second (not full deep sleep), up to 1s delay for deep sleep exit, little hardware modification.

    - Forget deep sleep mode and prefer standard sleep mode (IDLE) with only core enabled at minimal clock frequency, periodic TPS65070 state reading via timer interrupt, DEEPSLEEP pin configurated as interrupt via GP0(8)

    - ...?