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PMIC TP65217BRSLR SYS Pin operation

Fabio Rofino
Intellectual 600 points
Other Parts Discussed in Thread: TPS65217, AM3352

"In case AC or USB is not present or blocked by the power path control logic (e.g. in OFF state), the battery
voltage always supplies the system (SYS pin)" This is a operacional statement of PMIC datasheet.

I want to know with there is some procedure or even a specific family where the SYS pin remain without voltage applied from battery on PMIC OFF state.

regards,

ROFINO

  • 0
    TI__Genius 10885 points
    Hi Fabio,

    Can you use the sleep state by pulling PWR_EN low?
  • 0 in reply to Richard Solarski
    Intellectual 600 points
    Today I have PWR_EN (pin 9 TPS65217) routed direct to processor AM3352 pin PMIC_POWER_EN (pin C6). The process to use this pin is controled by RTC during de use of POWER OFF functionality.

    I can make some modifications on schematic and layout to provide a GPIO acess to this pin and create an low level signal on PWR_EN controlled by software.

    This sugestions mean that, on SLEEP mode, the PMIC doesn´t route the battery to VSYS pin?
    Do you sugest another arrangement to acess the PWR_EN pin?

    NOTE: our schematics are with TI team. We sent by e-mail because of confidentiality.

    Regards,

    ROFINO
  • 0 in reply to Fabio Rofino
    TI__Genius 10885 points
    Hi Rofino,

    If AC is actively supplied it should not revert to the battery during sleep mode. The PMIC has to have some source for the SYS rail, so AC or USB would have to be present if you cannot run off the battery.

    I don't have another suggestion for accessing the pin, as this really depends on your application and how you would want to bring the PMIC back from SLEEP to ACTIVE.
  • 0 in reply to Richard Solarski
    Intellectual 600 points
    Hello Richard,

    Just to clarify the operation on sleep mode: if we remove AC and USB fromPMIC during the SLEEP state, what will be the voltage on SYS pin?
  • 0 in reply to Fabio Rofino
    TI__Genius 10885 points
    If the AC and USB supplies are disconnected, the SYS pin will revert to the BAT pin and the PMIC will likely transition to the OFF state.

    The voltage on the SYS pin in the off state will always be battery voltage. The sleep state will allow the PMIC to act like it would in off state (regulators disabled), but still supplying SYS from the AC or USB.
  • 0 in reply to Richard Solarski
    Intellectual 600 points

    My main situation is: I have loads connected to VSYS pin all the time. During the OFF state, my battery power few circuits and discharge itself.

    Can I make some arrangement to cut the energy of the battery to PMIC during the OFF state and reconect the battery again in ACTIVE state?

    Sounds like a not usual workaround but we need to make some arrangements to make possible to operate with this topologie, of course without create an spurious behaviour of PMIC.

  • 0 in reply to Fabio Rofino
    TI__Genius 10885 points
    Hi Fabio,

    Would a load switch from VSYS to the external loads be acceptable? Then it could be enabled by a regulator in the ACTIVE state, which should disconnect the loads from the battery during the OFF state. Would this work for your application?
  • 0 in reply to Richard Solarski
    Intellectual 600 points

    Hi,

    Over the weekend we thought something in this direction. So we will control the load instead the battery connection.
    We are creating a prototype to validate this circuit.

    Regards.

  • 0 in reply to Fabio Rofino
    Intellectual 600 points

    We used a load switch controlled by one ot the PMIC´s LDO to power on/off  our loads attached to VSYS pin.

    With this approach, we was able to turn-off the load during PMIC OFF state. Now, we have near to 7uA of battery discharge during OFF State.

    Regards.