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Synchronizing and Phase Distribution using the UCD9248

Lukas Holm
Prodigy 110 points
Other Parts Discussed in Thread: UCD9248, UCD9246, UCD9224

My design uses two UCD9248. Together they control eight voltage rails with a total of 12 phases. Is there a way to synchronize and distribute all the phases? When I try to use the Sync-Out and Sync-In pins, the automatic phase distribution gets lost.

  • 0
    TI__Genius 13700 points

    You can configure one of the UCD9248 controllers as a master, set the Sync_Out pin to Rail#1.  Route Sync-Out signal from first controller to second controller's Sync_In pin.

    The Master will distribute its own phases accordingly.

    Then configure the second UCD9248 as a slave, define all configured rails as to accept Sync-In signal.

    At this point, all configured rails in the second controller would occur coincident with the sync signal, use the Sync_Offset command to adjust the phasing among the rails in the second controller with respect to the first controller.

    Information about Synchronizing capabilities can be found in the Using the UCD92xx Digital POL Controller Design Guide (SLUU490) which can be found at Help --> Documentation & Help Center, when the help window pops up, click the UCD92xx tab

    NOTE: The numbering in the PIN DESCRIPTION table of the UCD9248 datasheet has an error, the pin numbers for Sync_In and Sync-Out are revesred in the table.

    NOTE: Using a host other than the Fusion Digital Power GUI to perform the read command for SYNC_OFFSET will return a negative number for offset values greater than 1023.  The controller interpretes the value correctly internally, it is only the PMBus read command that is affected.

    This imformation applies to the UCD9224, UCD9246 and UCD9248.