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TPS65218D0: DOUBT REGARDING PB PIN

Anasur Rahman
Prodigy 30 points
Part Number: TPS65218D0

Actually I have a doubt regarding the pin PB.

Scenario:

I have given pullup to the PB pin and i also not provided any switch to the PB pin.

In above mentioned condition, Does DCDC6 will turn on ? Because DCDC6 is connected to the VDDS_RTC of the microprocessor.Once VDDS_RTC gets ON only, Processor can drive the PWR_EN as high and then power up sequence will get initiated in the PMIC. Please reply ASAP.

  • 0
    TI__Mastermind 18290 points

    Hi Anasur,

    The DCDC6 (and DCDC5) status actually depends on the FSEAL bit (REG05[7]) which is reset to 0b after a power cycle.

    If the FSEAL bit = 0b, DCDC6 will be controlled by the sequencer and the DCDC6 Enable bit. When DCDC6 is controlled by the sequencer, the rail should not power up until a WAKEUP event is triggered. The PB only triggers a WAKEUP event when the pin is pulled LOW so if PB remains pulled HIGH you will need to use one of the other WAKEUP conditions to start the power up sequence (See Section 5.3.1 in the datasheet).

    Once you trigger the WAKEUP event, DCDC6 should power up at STROBE1 in the sequence as long as you have input power at IN_BU or CC pin and DCDC6 enable bit is asserted.

    If the FSEAL bit = 1b, DCDC6 will remain on even in the OFF state. Under this condition, the PB status doesn't affect DCDC6 output. DCDC6 will be active if there is valid power at IN_BU or at the CC input (Coin Cell battery). If main power is removed from the device to cause a full reset, DCDC6 will shutdown due to lack of power and the FSEAL bit will return to 0b.

    Regards,

    James