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TPS53647: Power Supply Sequence

Mark Guastaferro
Genius 11645 points
Part Number: TPS53647

Does the TPS53647 have a required power supply sequence for VIN and VDD? 

The data sheet figure and the Multi-phase FAQ forum post imply that the 12V VIN is enabled before the 5V VDD voltage.  But the EVM User Guide indicates that 5V is enabled before the 12V.  

Also, does the associated power stage(CSD9549x in this case) have a power sequence requirement as well?  The respective supplies for the controller and the power stage will be tied together. 

  • 0
    TI__Expert 4060 points

    Hey Mark,

    There's isn't a 100% strict requirement on the sequencing for the TPS53647 so long as the 5V and 12V supplies to the controller and power stages are stable before turning the regulator output on. That said, we generally recommend having 5V come up first as it allows for a modicum of protection in case there's an issue with the higher power 12V rail. The power stage has some built in protections that can help save the FETs in case of a VIN supply short.

    Let me know if you need anything else!

    Cheers,

    Carmen

  • 0 in reply to Carmen Parisi
    TI__Genius 11645 points

    Thanks Carmen

    In our case, it’s possible for the 5V input to be present without the 12V input for an extended period of time (hours or days in a lab environment). Any concerns with this?

  • 0 in reply to Mark Guastaferro
    TI__Expert 4060 points

    Hey Mark

    I don't see why it would be an issue so long as you aren't enabling the output. What kind of testing are you running?

    Carmen