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ISO7220A: Digital isolator is failing when ever driver fails

hema danda
Prodigy 160 points
Part Number: ISO7220A

ISO7220A is used to drive LLC PWM pulses of 100khz- 250khz to PWM driver ucc27714DR. whenever pulses come into mosfets by sensing 400V at the input at that time both driver and Digital isolator is failing. 

For your reference, I am attaching some images of schematics.

  • 0
    TI__Mastermind 21110 points

    Hello,

    Thank you for reaching out. Could you explain what you mean by the driver and digital isolator failing? Are you seeing incorrect outputs on the digital isolator or do you mean the isolation barrier is failing?

    Regards,
    Darrah

  • 0 in reply to Darrah Merillat
    Prodigy 160 points

    Isolator IC is damaging. IC is consuming more current when given VDD externally after failing. 

  • 0 in reply to hema danda
    TI__Mastermind 21110 points

    Hello,

    Thanks for clarifying. Could you answer the below questions about your set up and the device's status after being damaged?

    • What voltages are being applied to the isolator input pins?
    • Is an increase in current consumption the only indicator of damage?
      • Is there any physical damage visible on the isolator?
      • Are the correct signals being seen on the output pins? If not what is being seen (ex: output stuck high/low)?
    • Can you measure the resistance between the pins on each side and their respective grounds, for example VCC2 to GND2 and VCC1 to GND1?
      • Please remove the device from the PCB before measuring
    • Can you measure the resistance between pins GND1 and GND2?
      • Please remove the device from the PCB before measuring
    • How far from the device are C20, C22, and C19 from the isolator in your layout? Decoupling capacitors should be placed no more than 2mm from their respective supply pins.

    This information will help us determine how the device has been damaged as well as potential causes of the damage.

  • 0 in reply to hema danda
    TI__Guru 54815 points

    Hi Hema,

    I am following up to check if you will be able to provide the information requested by Darrah in her previous post. Please do help us with the requested information so that we can help debug the issue. Thanks.


    Regards,
    Koteshwar Rao