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ucc27531

Xiaoming Kong
Prodigy 90 points
Other Parts Discussed in Thread: UCC28180, UCC27531

Hello Sir

I use UCC27531 in a 1.5kW PFC circuit as  MOSFET drive working together with UCC28180, The IN pin connects to the Gate pin of 28180 via a 100ohm resistor, while the gate of MOSFET is connected to the OUTH pin via a 10ohm resistor, and  to the OUTL pin via a diode & 3ohm resistor. However, PFC can only output a power of about 400W.  UCC27531 damaged (no output) when the power was going over 400W. The UCC27531 is biased with the same 15V power supply as UCC28180, and shares the same control ground with UCC28180. What might be the renson of the failure ?

best regards

xiaoming

  • 0
    TI__Expert 3200 points
    Hi Xiaoming,

    There could be many reasons for the failure. Please confirm only the UCC27531 fails in your circuit. Are you willing to share the schematic and some component information privately? There may also be the need for some oscilloscope captures on a couple of your circuit nodes. Let me know if you can share this information or not, we can set up a discussion outside of this E2E thread for privacy.
  • 0 in reply to Brian Johnson96
    Prodigy 90 points
    Hi Brian

    Thanks for your quick reply.

    The failure just occurred on 27531 only. I tested several times, and every time showed the same result.

    It would be quite nice you can have a review on the schematic and pcb, but how can i send the files or pictures to you ?

    best regards
    xiaoming
  • 0 in reply to Xiaoming Kong
    TI__Mastermind 25570 points
    Hello Xiaoming

    Can you send the files to me at colingillmor@ti.com. A .pdf of the schematic is fine. If you can send me the PCB Gerber files that would be ideal (much easier to follow than .pdf)

    It's hard to say for sure but my initial suspicion is that there is an overvoltage condition happening on the driver - maybe a transient voltage on VDD or ground - I've seen that kind of thing happen in other applications.

    Regards
    Colin
  • 0 in reply to Colin Gillmor
    TI__Mastermind 25570 points
    Hello Xiaoming

    Thanks for sending me the files.
    My main finding on the layout was - 'The return path from the driver ground pin to the source of the power MOSFET is very long and I would expect that there are very significant voltages generated in it during PFC switching action, especially as the Power MOSFET is turned off. This is the first place I would look to investigate the failures. You should put a ‘scope probe ground at the driver GND pin and probe the source terminal of the MOSFET – this is a high speed event so you need to minimise the length of the ‘scope ground lead or use a ‘tip and barrel’ measurement.'
    I'm glad that you were able to update the layout and thanks for the email confirming that you can now run the PSU up to full power.

    I'm marking this thread as 'answered' but please don't hesitate to re-post if something else pops up.

    Regards
    Colin