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UCC28019A: Inquire UCC28019A Brown in and Input OVP reference circuit

user4773172
Intellectual 1410 points
Part Number: UCC28019A

Hi Sir,

May I learn from you if UCC28019A have Brown in and Input OVP reference circuit can provide to my customer?

Please feel free to contact me via mail.

Thank you.

Edward Chen

  • 0
    TI__Mastermind 34465 points

    Hello Edward,

    The UCC28019A has a VINS input which senses the AC line signal. At startup the pfc is disabled until VINS exceeds a threshold of 1.5V.
    This is the brown in function.

    It is unusual to require an OVP function on the pfc.
    This is because even if you shut off the pfc your output voltage will continue to rise because the boost diode will be forward biased and so the
    high voltage output will continue to rise. This is a particular characteristic of the boost circuit.

    However if you still require an OVP shutdown you can measure the VINS signal with an external opamp and when it exceeds your threshold value
    you can pull down on VSENSE pin with an open collector output.

    Pulling VSENSE below 0.8V stops the pwm . This is the so called open loop protection feature (OLP)  on VSENSE

    Regards

    John

  • 0 in reply to John Griffin1
    TI__Intellectual 1410 points

    Hi John,

    Hope everything doing well.

    Thank you for your suggestion, I will discuss with customer to see their feedback.

    Thank you.

    Edward Chen