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Original question:

DRV8662: DRV8662 IC OVER HEATING

DRV8662: DRV8662 IC OVER HEATING?

Kyle Bradley
Prodigy 30 points
Part Number: DRV8662

Hi, 

I am having a similar issue to Dinesh in terms of my IC overheating within my circuit. It seems as though my resistance in my circuit from Vboost to GND is around ~775kΩ before power up. As soon as I power up, the current draw increases to almost 700mA with no load. When checking the same resistance again it has ranged anywhere from 16Ω to 1kΩ depending on the board I've checked on. Either way it is considerably shorter.

The weirdest part is this is the second iteration of the board, and in the first case I had screwed up the resistive divider, but when I modified it and cut traces, I was able to pull my 105V as expected. (Actually running slightly above but still did not see any issues).  The only change between the board was correcting the resistor divider and making the board slightly more compact. I'm not sure how this would cause issues though as the board was already compact. 

Do you have any idea how this could be occuring?


Thanks,

Kyle

  • 0
    TI__Expert 8832 points
    Hi Kyle,

    This points towards some sort of short in your circuit. Are you able to share your schematic/layout? Do you need me to send you an email?
    Can you measure the voltages at the FB pin and SW pin? What value for REXT are you using? What inductor are you using?
  • 0 in reply to Kelly Griffin
    Prodigy 30 points
    I can send you my schematic and layout if you email me directly. (kbradley5393 @gmail actually works better than the attached.)

    The SW pin was just under the supplied 5V. FB I would need to double check.

    REXT= 7.5k
    Inductor is a 4.7uH, NRS8030T4R7MJGJ.

    Feel free to email either location directly and I can send the schematic files and images
  • 0 in reply to Kyle Bradley
    TI__Expert 8832 points
    Hi Kyle,

    Thank you for replying via email and letting us review your schematic. After reviewing this, I believe we found the issue was the resistive divider needs to be set so that the boost voltage is <105V. Setting the boost voltage above 105V can cause the internal FETs to breakdown and the part may overheat/pull a lot of current.