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UCC28251: PRE BIAS

Ramakrishnam Raju
Prodigy 10 points
Part Number: UCC28251

HI,  got confused, what is pre bias and pre biased start up with respect to UCC28251.

  • 0
    TI__Mastermind 34465 points

    Hello 

    Pre bias startup is a condition where there is a voltage on the output capacitors before the power supply starts up.
    This may be due to a slow discharge of the output before the DC input is restored to the system.
    With a synchronous rectifier output this can be an issue because during startup the output is delivering power to the input.
    If the forward rectifier turns off during this interval the load current has no path to flow and you may see an excessive voltage on the forward rectifier.
    This may destroy the part.
    Therefore it is important that the UCC28251 has the ability to operate during a pre bias condition.
    This feature is described in detail in the data sheet.
    Regards
    John