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TPS65910 power consumption on VBACKUP

Frank S.
Prodigy 90 points
Other Parts Discussed in Thread: AM3715, TPS65910

Hi,

what is the typical power consumption on VBACKUP in "Device BACKUP state"? We use the TPS65910A1RSL with a AM3715.

The device if OFF - that means VCC/VBAT=0V and VBACKUP is connected to a 3V back-up battery (not rechargeable). The internal RTC is enabled and works well. The backup registers are not really used and all back-up battery charging settings are default values.

The expected value according to data sheet was typical 6uA (datatsheet page 10) or better. We measure 12,33uA battery current...!?

Is a backup battery capacitor Cbb required?

Thanks

FS

  • 0
    Prodigy 90 points

    Hi,

    i checked the VRTC mode for the TPS65910 according to this thread http://e2e.ti.com/support/power_management/pmu/f/43/t/162324.aspx

    The  VRTC_OFFMASK Bit in "VRTC internal regulator control register/VRTC_Reg (0x1E) is by default 0. I also tested with VRTC_OFFMASK = 1. The result during the device is OFF (VCC/VBAT=0V) is the same:

    VRTC_OFFMASK=0 (low-power mode during device OFFstate) -> 12,3uA

    VRTC_OFFMASK=1 (full-load capability during device OFFstate) -> 12,3uA

    What is the expected difference between these two modes?


    FS

  • 0 in reply to Frank S.
    TI__Intellectual 2090 points

    When VRTC_OFFMASK = 1, VRTC LDO is kept enabled in full load mode in OFF state -> it consumes more current (additional ~ 15uA).
    But here we speak about backup state with regards to TPS65910 (VBAT = 0).

    This bit has no effect in backup, VRTC LDO is always in low power mode in backupWhen VRTC_OFFMASK = 1, VRTC LDO is kept enabled in full load mode in OFF state -> it consumes more current (additional ~ 15uA).

    But here we speak about backup state with regards to TPS65910 (VBAT = 0). This bit has no effect in backup, VRTC LDO is always in low power mode in backup