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Original question:

Using LM324 As a buffer

LM324: Buffer/Voltage Follower

Nishan Withana
Prodigy 90 points
Part Number: LM324
Other Parts Discussed in Thread: TLV9004

I want to use a buffer ic for the outputs generated by the Arduino Due microcontroller. Can I use LM324 for this application? Is there any application circuit to use LM324 as a buffer? I have generated PWM outputs from the MCU and need to provide them for the igbt gate driver. Need to use the buffer between the MCU and the igbt gate driver.

  • 0
    TI__Mastermind 30600 points
    Hi Nishan,

    How much current do you need for the IGBT gate driver? That spec will drive your choice of amplifier. While the LM324 is a good amplifier, there are many better and more modern amplifiers that might be better starting points. I recommend looking at the TLV9004. However, both devices are unity gain stable and can be used in a buffer with some cap load. If the IGBT gate driver has a large input capacitance, you may need to compensate the circuit.

    Best,
    Paul
  • 0 in reply to Paul Goedeke
    Prodigy 90 points
    I am not sure about the exact current that is required by the IGBT gate driver. The datasheet of the gate driver indicates that the maximum input bias current should be 300 micro amperes. What current range does the LM324 ic can be used as a buffer? Sir can you please expalin what you meant by "compensating the circuit"
  • 0 in reply to Nishan Withana
    TI__Mastermind 30600 points
    If the driver only needs 300uA, then there are many op-amps will work. Is there a particular reason why you'd like to use the LM324? It has some quirks that can make it a little more difficult to use. The TLV9004 is a better choice.

    As far as compensating, that's a reference to the stability of the circuit. I recommend taking a look at TI Precision Labs and watching the videos on stability: training.ti.com/ti-precision-labs-op-amps. If you can find what the input capacitance of the IGBT gate driver is, that will help you make some circuit design decisions. If it's a low capacitance, then a simple unity gain buffer circuit like this one should work. www.ti.com/.../getliterature.tsp

    Let me know if you have any more questions.
    -Paul
  • 0
    Guru 140200 points
    Hi Nishan,

    can you give us a schematic of your planned circuit?

    Kai