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UCC2895 has some problems

Part Number: UCC2895
Other Parts Discussed in Thread: UCC27714,


We have some problems with power supply using UCC2895.

  1.  UCC2895 is short-circuited and damaged between VDD and GND .
  2.  Full bridge circuit MOSFETs may be damaged.

The symptom does not occur on the power board alone, and problems occur when it is connected to the device.

The device is a 400W rated dot printer.

Even if I observe VCC of UCC2895, no surge voltage etc. is observed.

The combination of UCC2895D and a third-party gate driver (FAD7191) does not cause damage to the full-bridge MOS FET.

I have a problem with the combination of UCC2895 and UCC27714.

  1.  Why do we reach such a FET destruction mode?
  2.  What is the optimal method for GND connection on a single-sided board?

It is possible to submit a schematic.

Please help check it and provide the way how to solve.

Thank you.

  • Hello,

    If the FETs are being damaged in the HBridge it is most likely do to one of the following excessive current, excessive voltage or excessive teampature.

    Double check this in your design with a current probe and voltage probe and thermal camera.

    If VDD of the UCC2895 is shorted ground generally this means that one of the pins of the UCC2895 was exposed to an excessive over voltage or any of the UCC2895 pins were pulled more than -300 mV below ground.  The UCC2895 is most likely getting damaged due to electrical overstress.

    I noticed that your design is for 400 W  do you know there is a 600 W EVM using the UCC28950 and the UCC27714 available for evaluation that may fit your needs.  You can find it at the following link.