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DC input problem of UCC28070A for VINAC pin

Satoshi
Guru 19645 points
Other Parts Discussed in Thread: UCC28070A

Customer want to know the case of DC input for UCC28070A.

（DC input to VINAC）

①If DC input to UCC28070A's VINAC pin, what is the thought for unusual move?

　　Is it possible to affect PWM output?

②I think that DC input is not have possibility of damage, is it correct?

We understand DC input is not recommended, but we want to know operating principles.

Best regards,

Satoshi

  • 0
    TI__Mastermind 31580 points
    Hi Satoshi-san,

    The UCC28070A uses the zero crossing of the AC mains supply to trigger an update to the Vff value in the multiplier. If the controller is run from DC then the Vff value will not be updated and it is difficult to determine what Vff value it will use.

    Can you tell me more about the application and maybe we can recommend another PFC controller that may be more suitable to run from a DC bus.

    Regards

    Peter