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IR2184 gate driver questions

Discussion in 'RE Projects' started by MatheusLPS, Feb 4, 2012.

  1. MatheusLPS

    MatheusLPS New Member

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    Hello people.

    I am designing an power inverter.

    My idea is transform 12VDC in 120VAC@60Hz.

    I will make a signal PWM at 25Khz comparing a triangle wave and a sini wave. OK.

    But, to make things simpler in the beginning, I am testing with an static root wave at 25Khz provided by a 555 IC.

    I threw this signal on a IR2481 gate driver to switch my two IRFP460 mosfets.

    So I started with a basic circuit:

    [​IMG]

    This one is working very well. I am using a single power supply with 12VDC. Look the all the power lines and grounds are the same.

    The signal at my gate is ~12V. Nice:

    [​IMG]

    And measuring the voltage across the resistor I came with this:

    [​IMG]

    12Vp.p. It looks that is working. :D.

    BUT.....

    Lets say that I need to work with to separated power supply. One will be my power supply for the control circuit (12V).

    Lets consider that I will use another power supply with 12VDC to power the mosfets and capacitors....

    So now I have to power that has different ground lines......

    My problem is the COM PIN of the IR2184. Accordingly to the datasheet, I need to connect it to the ground of the "HIGH" power supply. When I say "HIGH" I am referring to the power supply that feeds the mosfets.

    In this example, the power supply is 12V, but it can be 24V, 100VDC..... I do not know yet.....

    I connect the COM PIN to there and what happened? My IR2184's burned... twice........

    What is the correct way to connect the two power supply's and my control circuit?

    bye
     
  2. MatheusLPS

    MatheusLPS New Member

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    Renewable Energy section?

    The topic was moved........ but it is a question about electronics....

    bye
     
  3. alec_t

    alec_t Well-Known Member Most Helpful Member

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    Did you have the COMs of both supplies connected together?
     
  4. dave

    Dave New Member

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  5. ronsimpson

    ronsimpson Well-Known Member Most Helpful Member

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    I modified you drawing.
    100V on the MOSFETS.
    12V on the IR2184.
    Removed +5V on /SD pin. left it open.

    See data sheet.

    The two power supplies have a common ground.
     
  6. MatheusLPS

    MatheusLPS New Member

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    I do not know if helps....

    Well, I changed the output from 555IC to 5V, providing 5V at VCC of teh 555 IC....

    Now, my third IR2184 did not burn... but when I turn ON the mosfet's power supply, only the upper one become very very hot..... and I turn it off....

    I connected the circuit with two ATX power supply, like this:

    P.S: I forgot to add the resistor on the gate, but on my circuit, I added two 22 ohms resistors. Each one to each gate.

    http://img.photobucket.com/albums/v222/ahhh/circ-1.jpg

    OK. I just burnt the third IR2184.... I need to buy more tomorrow.......

    Well, accordingly to the datasheet , the SD PIN must be connect to 5V?

    I will try your circuit... This one is different of all I have already tried.....

    In a few days i will update everyone....

    Thanks......
     
  7. ronsimpson

    ronsimpson Well-Known Member Most Helpful Member

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    It has a resistor inside the IC that pulls the pin to +5V if you do not connect it. You could connect to VCC.

    VCC should be between 10 and 20 volts. Not 5 volts.
    I think you were driving the IR2184 with a 555IC and now you drive it with 5V. You much have a AC input like from a 555. You can connect the input to ground but you can not connect it to a + level for more than a short time.
     

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