igbt driver

Discussion in 'The Projects Forum' started by Tate, Nov 1, 2010.

  1. Tate

    Thread Starter New Member

    Mar 8, 2010
    11
    0
    I am looking at using an IGBT transistor for a project I am working on. The datasheet states that the Gate Voltage is +/- 20volts.

    I am trying to use this to amplify the 40kHz, +6/-6volt signal from a 555 timer.

    The question is, can I use a voltage amplifier to get the signal up to 20 volts to provide the positive and negative bias for the IGBT or do I need to use an IGBT driver chip?

    I have built a couple audio style amplifiers but this is the first time I have used an IGBT.
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    What is the part number of your IGBT?

    It's starting to sound like you want to build a Class D amplifier. Is that correct?

    IGBT's are a cross between a transistor and an enhanced MOSFET. They have a collector, an emitter, and a gate.

    With an N-channel IGBT, generally the collector is in cutoff (not sinking current) when Vge = 0v, and the collector is sinking maximum current when Vge is 10v to 15v.

    The +20v/-20v you're seeing is likely the absolute maximum Vge. You really don't want to get too close to the maximums, unless you like replacing your IGBT's frequently.
     
  3. Tate

    Thread Starter New Member

    Mar 8, 2010
    11
    0
    I will have to look for the part number when I get back home from work.

    I am pretty much building a class D amp. I am wanting to use it to power a ultrasonic transducer that has a frequency of 40kHz. The transducer has a harmonic resistance of 50Ω.

    I was told to try to use a IGBT transducer because it handles the impedience of the load better. Is this correct?
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Well, IGBTs are easier to drive than transistors, because transistors require a good bit of base current, whereas IGBTs are a hybrid of a MOSFET and standard bipolar junction transistors - you charge and discharge the gate instead of supplying current to a base.

    I don't know that you'd get any benefit in using a IGBT over a power MOSFET at low voltages. Usually, you'd want to use a MOSFET for switching DC at low to moderate voltages (say up to 200v or so), and then IGBT's over that. For switching low frequency AC, you'd want to use a thyristor; an SCR or TRIAC. Thyristors, once switched on, stay on until the current through them falls to near-zero.
     
Loading...