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UCD9244 - VTRACK Pin

Richard Marsh
Intellectual 760 points
Other Parts Discussed in Thread: UCD9244, UCD9222

Hi,

 

I would like to control one of my UCD9244 rails by reference to an external rail that is not part of my UCD9244 design.

I was expecting to use the VTRACK pin, but I cannot find it in the UCD9244 datasheet.

Fusion allows me to select the "Track the external vtrack pin" option for a UCD9244 design.

On the UCD9222 the Vtrack pin is combined with one the AUXADC pins, is that the case with the UCD9244?

 

Cheers,

 

Richard

  • 0
    Intellectual 760 points

    As an alternative to the VTRACK pin, does the UCD9244 support the GPIO/Sequencing Pins to enable rails.

    The doc "Using the UCD92xx Digital Point of Load Controller - Design Guide" does not list the sequencing pins for the UCD9244 in table 4-2 (page 63).

    Neither do I get a GPIO tab in the Configure section of the Fusion Tool.

     

    Cheers,

     

    Richard.

     

  • 0
    TI__Genius 13700 points

    Due to limitations in pin configuration when implementing the VID capability for four rails, the External Vtrack pin was not included in the feature set for the UCD9244.

    I've asked the Fusion Digital Power Designer GUI developer to gray out the ability to choose Track the external vtrack pin as an option, the controller does still have the capability to track an internal rail.

  • 0 in reply to Richard Marsh
    TI__Genius 13700 points

    The GPIO/Sequencing capability was also sacrificed to implement VID on four rails, the only option for sequencing into the UCD9244 is the PMBus_CNTRL pin.

    Maybe the UCD9222 is a viable option for your design, it can support two VID rails and it has individual Enable pins for each rail which follow the active state set for the PMBus_CNTRL pin configuration.

  • 0 in reply to Brad
    Intellectual 760 points

    Hi Brad,

    Space limitations mean I have to use the UCD9244, rather than two UCD9222.

     

    I have one external rail I have to sequence in the middle of the 4 internal rails.  It sounds like my only option is the PMBus_CNTRL pin.  Also sounds like I don't have the option of individual Power Goods either.

     

    If I use the PMBus_CNTRL pin to control the rail sequencing, does that mean connecting Fusion via USB_to_GPIO pod will cause my rails to shut down? i.e. does Fusion waggle the PMBus_CNTRL pin??

     

    Cheers,

     

    Richard 

  • 0 in reply to Brad
    Intellectual 760 points

    Hi Brad,

    I now don't need to sequence an external rail with the UCD9244 rails.  However I am using the UCD9244 to provide the rails for the C6678 and this device needs to sequence the rails in order.  Time based sequencing is not sufficient, because rail #2 should not be turned on if there is a problem with rail #1.

    When you say "The GPIO/Sequencing capability was also sacrificed to implement VID on four rails" you don't mean that the internal rail sequencing was sacrificed do you?  i.e. can you set up the UCD9244 to turn on rail #2 only once rail #1 has turned on and is stable?

    In fusion I can only see sequencing based on time, not a dependency on an internal rail.

     

     

    Richard