Please help - Tc4429 blowing

Discussion in 'The Projects Forum' started by woerr, Apr 5, 2015.

  1. woerr

    Thread Starter New Member

    Apr 5, 2015
    21
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    I need some help, I am blowing my inverting mosfet driver.

    The circuit is a motor driver to run a 12v motor.
    uno32 - H11L1 opto coupler - tc4429 mosfet driver - irlb3034. - 30amp dc motor

    My problem is that the tc4429 chip keeps breaking, first it gets hot but still works and eventually stops working at all.

    When looking at the signals with a oscilloscope i see what looks line a sine wave the distance between peaks is about 5mV

    I suspect that the might be the fact that the battery powering the circuit is not connected well enough. I will test tomorrow to check. But I would like ideas what else the issue could be.

    [​IMG]

    Link to the circuit.
    https://drive.google.com/file/d/0B-S6XnCqN9GQRUxYdlc2MzVwMlk/view?usp=sharing

    Thanks
     
  2. AfdhalAtiffTan

    Active Member

    Nov 20, 2010
    117
    11
    How far is the driver from the mosfet? Do you use any gate resistor? Is the driver properly powered? Any chance of looking at scopeshots at all related nodes?
     
  3. woerr

    Thread Starter New Member

    Apr 5, 2015
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    0
    - Driver is about 10cm from the mosfets
    - there is a 120Ohm resistor on the mosfet gate and 20k resistor on the tc4429 gate
    - Driver is powered directly from 12v battery
    - I will upload some scope shots as soon as I can

    https://drive.google.com/folderview?id=0B-S6XnCqN9GQdlpGX1F1VTNpQkE&usp=sharing

    Any ideas? I am getting desperate.
     
    Last edited by a moderator: Apr 6, 2015
  4. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
    2,795
    831
    I can't see your pictures clear enough to see anything Google Drive has an interface that's difficult on a mobile device. That's why I dislike externally hosted pictures. Can you upload them here? Here are some tips.
     
  5. woerr

    Thread Starter New Member

    Apr 5, 2015
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    uploaded images

    Also note that the chips blow only when a motor is connected to the mosfet

    uploaded diagram
     
    Last edited by a moderator: Apr 6, 2015
  6. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
    2,795
    831
    If I'm reading you schematic correctly, I see a problem.

    What is the significance of the grey labels?

    Your Gnd and Vcc appear to be between -15VDC and +9VDC. This is a supply of 24VDC; the maximum rating for the TC4429 is 18VDC. You're way over specs.

    This is a sure recipe for magic smoke. Let us know if my interpretation is wrong.

    Capture.png
     
    Last edited: Apr 6, 2015
  7. woerr

    Thread Starter New Member

    Apr 5, 2015
    21
    0
    labels are wrong. it is 12v.

    I seem to have fixed it by running separate wires to the battery instead of all on a single rail, System is running off a battery and alternator. the problem must be motor noise. please suggest a method to filter unwanted noise and voltage drop.

    also a way to deal with back voltage from the motor, apart from a diode.
     
  8. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    Do you have a snubbing diode across your motor?
     
  9. woerr

    Thread Starter New Member

    Apr 5, 2015
    21
    0
    yes I do, 25us 60 amp
     
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