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UCC28083: UCC28083' issue

Hope Chen
Expert 1030 points
Part Number: UCC28083
Other Parts Discussed in Thread: LM2596,

1，SPEC:INPUT:DC 110V；OUTPUT: 36V/6.5A、90V/0.5A、24V/2A( transfer through the LM2596 form 36V)

2，Question description

a,The startup cannot be started (no output), and the power with normal output when replace the new UCC28083

b,After running 5-10 minutes with normal output , the power  is no output. but the power with normal output when replace the new UCC28083

c,We found the NG's UCC28083 can work normally when INPUT: DC 60V（ VDD: 10V）.but when the input voltage is higher than 80V（ VDD: 14V），the output will fall to zero.

 in this case we try to test OUTA waveform, found UCC28083 at the instant of the start will be a normal square wave (as shown in the figure below), try to start the chip

the waveform and SCH is as below

3,

    

  • 0
    TI__Mastermind 27105 points
    Hi Hope,

    Thanks for your interest in UCC28083. I suggest installing a decoupling cap from the VDD pin to ground, ideally close to the controller itself. Are any other components getting damaged at 80Vin? WIll the controller start up when Vin is changed back to 60V?

    Best Regards,
    Ben Lough
  • 0 in reply to Benjamin Lough
    Expert 1030 points
    Dear Ben，
    After testing with installing a decoupling cap from the VDD pin to ground and，the issue persists . The ucc28083 cann't satrt up when Vin is changed back to 60V from 80V .
    There has no a significant difference between the good and the NG' ucc28083 form the IV curve also
    Thanks a lot