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UCC28070: GDX OUTPUT SIGNALS OSCILLATE BETWEEN 89KhZ TO 115KHz

Eddie Loy
Intellectual 850 points
Part Number: UCC28070

IN TESTING THE PFC CONTROLL BOARD I COULDN'T HELP BUT NOTICE THAT THE GDX OUTPUT SIGNALS WERE OSCILLATING BETWEEN 89KhZ TO 115KHz.  THE WAY I SEE THIS IS THAT THE GDX SIGNALS COMING FROM THE UCC28070 (Pin #14 & Pin #17) ARE UNSTABLE AND WILL MOST LIKELY DESTROY THE POWER SWITCHES. 

NOTE : I AM TESTING ONLY THE SIGNAL PORTION OF THE PFC CONTROL BOARD.

Question #1: IS THIS NORMAL FOR THE UCC28070 IC?

Question #2: IF THIS NOT NORMAL, WHICH IC PINS MIGHT BE CAUSING THE GDX SIGNALS TO SWING BETWEEN  89KhZ TO 115KHz

Question #3 : DO YOU HAVE ANY POSSIBLE SOLUTIONS TO THIS PROBLEM, IF IT IS A PROBLEM?

THANK YOU

EDDIE LOY

  • 0
    TI__Mastermind 34465 points

    Hello

    The UCC28070 is a fixed frequency pfc controller.

    If the frequency is jumping between values then your application has errors in its implementation.

    I suggest you review your schematic design or post the schematic with gate drive signals if you require further help.

    Regards