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UCC28180: Not getting PWM pulse on 8th pin of UC28180

Balakrishna Marripati
Prodigy 85 points
Part Number: UCC28180

Hi Team,

I am not able to see pwm pulses at 8th pin of UC28180, I was applied 14.5Vcc at 7th pin.

Thanks and Regards,

Balakrishna

  • 0
    TI__Mastermind 30860 points

    Hello Balakrishna, 

    Thank you for your interest in the UCC28180 PFC controller. 

    PWM pulses at the GATE output (pin 7) depend on the conditions at the other pins of the controller. 
    For example, if the VSENSE input is open-circuit, an internal pull-down source (100nA) will trigger the open-loop fault protection function (OLP) and GATE output will be held off.
    Or some other fault condition may be detected, with the same consequence of no GATE pulses. 

    Can you please provide information about how your UCC28180 device is being tested?  Is it in a PFC circuit or in an open-loop test circuit? 
    In either case, please provide all of the input and output test conditions applied to your circuit when the symptom is observed. 

    Regards,
    Ulrich

  • 0 in reply to Ulrich Goerke
    Prodigy 85 points

    Yes, Thanks for your answer, now I am able to see PWMs.  can you please confirm my design in ok or not, based on your confirmation I will power up.

  • 0 in reply to Balakrishna Marripati
    TI__Mastermind 30860 points

    Hello Balakrishna, 

    I'm glad that you observed the PWM pulses. 

    I cannot review your schematic (it looks like 2 copies of the same thing) because the images are too fuzzy (low resolution). 

    I also saw that you posted the same request in a new E2E post, and I replied to that one. 
    I will close this thread, and we will pursue the PFC review request in your new E2E post. 

    Regards,
    Ulrich