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UCC27511A: UCC27511 damaged

Part Number: UCC27511A
Other Parts Discussed in Thread: UCC27511, UCC28070

HI TI team

I design 1200W that using PFC (ucc28070) and drive ic (ucc27511)
I found that when the load is between 0 and 300W, AC instantly switches from 90Vac to 264Vac or from 264Vac to 85Vac
In this case, the GDB pin driver IC will occasionally be damaged
I want to know if the operation of switching AC instantly is allowed?
When UCC27511 is damaged, pin 3 is a short to ground.

PFC section for 1200W PSU.pdf

  • Hi,

    Our office is closed for the US Memorial Day holiday. My colleague will get back to you mid week. Thanks for your patience!

  • Hello,

    Thanks for reaching out.

    I can comment on UCC27511 section of your schematic. The UCC28070 is supported by a different team that you can reach out with different title thread.

    The UCC27511 operation should be OK so long as the signals around the IC are within the recommended operating conditions. 

    You want to check you gate signals, should be <18V. GDB signal should also be <18V and VDD signal should also fall within the same range.

    If IDS current somehow ends up at the gate, due to high dv/dt across the FETs, or MOSFET failure, the driver may also get damaged with failure mode typically output short to GND.

    You may add clamps at the driver's output to protect the IC against transients at the gate.



  • HI sir

    Please refer to the attached file

    1200W issue.docx

  • Hello,

    Output pins shorted to GND is consistent with damage of the internal pullup and pulldown transistors likely indicating some overshoot at the gate and/or the VDD pin. 

    Transients beyond the driver's ratings on the VDD and/or OUT pins are likely to create an EOS event. Clamp diodes directly on the OUT pins will help protect the output stage of the driver.

    Can you please clarify the image on the .docx file, are you sharing any signals around the driver IC?