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TPS659037: Battery backuped RTC

Johan Bendz
Prodigy 50 points
Part Number: TPS659037
Other Parts Discussed in Thread: AM5718, AM5728

Hi,

I want to have a battery to backup the RTC in TPS659037. Is that possible and how can that be done?

BR

Johan Bendz 

  • 0
    TI__Genius 10000 points
    Johan,

    Welcome to E2E! The RTC in the TPS659037 is powered by VCC1 (main input supply). Because it doesn't have another power supply option internally, a backup battery cannot be used to back up the RTC without an external solution.

    In order to implement a backup, you could switch on the backup supply on when the main supply dropped too low.

    Please let me now if you have any other questions.

    Thanks,
    Nastasha
  • 0 in reply to Nastasha
    Prodigy 50 points

    I have a system with TPS659037 and AM5718 and I could use the RTC in any of these.

    I will control the power on/off with the GPIO7 pin of  TPS659037, could I configure a mode to just feed the PMIC RTC in this condition or could I configure to enable only LDO9 and use the RTC in AM5728 instead?

    What would be the easiest way if I want to backup the RTC with a coin cell?

    BR

    Johan Bendz

  • 0 in reply to Johan Bendz
    TI__Genius 10000 points

    Johan,

    There is not a mode with just the PMIC RTC or just LDO9. The only way to use a back up battery would be to add a supervisor on VCC1 and turn on the backup when the main supply is too low. Unfortunately, this would not work well for a coin cell battery since the current consumption would drain the battery pretty fast.

    Thanks,

    Nastasha