Gate Driver for MOSFET Problem

Discussion in 'The Projects Forum' started by FardinBiper, Sep 26, 2012.

  1. FardinBiper

    Thread Starter New Member

    Aug 21, 2012

    I am having trouble with the following circuit in the image. I have read the datasheets and did everything they said in the circuit.
    The Driver is UCC37322:
    The MOSFET is IRLB3036GPbF:
    The controller I am using is Arduino.
    They all have a shared GND as stated in the gate driver datasheet.
    Keep in mind that there is about 30A going through the mosfet. No problem here cause the mosfet is made to handle this.
    I tested this circuit and unfortunately, the driver blows up. I don't know what I am doing wrong.
    I thought of current limiting resistor before the gate of the mosfet, however the Driver datasheet does not say anything about it. It actually says to position the mosfet very close to the output pins.

    Please Help!
  2. DickCappels


    Aug 21, 2008
    A resistor in series with the gate is a good idea; it reduces the Q of the gate circuit and reduces the chance of damaging oscillation.

    Your circuit looks fine as far as the schematic goes (I would add 100 ohms in series with the gate), but when you draw that 30 amps through the resistor and MOSFET, the voltages in the circuit might be significantly different from what the schematic shows. I am talking about resistance in the circuit and in particular in the ground connections -a small amount of resistance in a ground loop could affect the driver circuit and cause the destruction of MOSFET. Read up on ground loops.

    Additionally, is there a chance that the power to the controller is being affected? You might want to add some immense (low ESR) capacitors between the +12V and the source of the MOSFET.

    By the way, I would not start out with the full 30 amps. I would start with something more modest, like 500 ma to debug the circuit and the grounding. That way, you won't spend so much money replacing transistors or replacing other burned parts.
    FardinBiper likes this.
  3. shortbus

    AAC Fanatic!

    Sep 30, 2009
    Also did you follow the "layout" needs in the application sheet you linked to? The part about a ground plane under the driver was stressed as important to the working of the chip.
  4. praondevou

    AAC Fanatic!

    Jul 9, 2011
    Post a picture of your layout.
  5. help_mum

    New Member

    Sep 13, 2012
    I'm only a beginner at this but it looks like you have a direct short between the driver and fet. If the gate is opened by the gate driver and which is a variable driver I would say shouldn't the source be V+ the main power supply to pin D out is the driver 12v'

    Control is G (gate) main power is S (source) and output is D (drain)

    Unless it is a V- driver.

  6. shortbus

    AAC Fanatic!

    Sep 30, 2009
    Huh? Never heard of a "variable" gate driver. Gate drivers are a glorified switch or electronic relay that changes voltage and amperage levels from the logic signal to the mosfet gate.

    And what you are explaining about drain and source only applies to a P channel mosfet. The schematic shows a N channel mosfet.
  7. FardinBiper

    Thread Starter New Member

    Aug 21, 2012
    Thank you Dick Cappels,
    I added a 50 Ohm resistor before the gate of the mosfet in series. It does not blow up anymore :))
    I have looked at ground loops and I am using some very low gauge wire (thick) for the drain and source of the mosfet. Thanks for that.
    I found out the problem with the gate driver: The datasheet says that it can provide maximum 9 amps on the first page, but when I went deeper in it, I found out that it can only provide 9 amps for "several hundred nanoseconds". I was running this thing for 300 ms :)) Thats why it blew up.
    I am not worried about the mosfet. If you look at the datasheet, it has some impressive characteristics. When I run 30 amps through it, it is just warm to the touch. Does not even get hot.