Half Bridge and full Bridge driver with LSTTL input

Discussion in 'General Electronics Chat' started by timlauer01, Nov 22, 2012.

  1. timlauer01

    Thread Starter New Member

    Nov 22, 2012
    2
    0
    Hello all,

    I am stuck on problem to drive these IRS 184 and IRS21844 driver for my IGBT/MOSFET. I tried using comparator and OPTOcoupler and the signal from my function generator without success. The LSTTL is lower powered then the TTL output. I read some articles how the circuit would look around this output but I found no device to convert the signal off the shelve. To drive direct is causing shortage issues on the MOSFET/IGBT because both channels for inverted and non-inverted are on or off at the same time and very low performance at higher frequencies around 800 KHz and higher. I want the amplifier stage to use for higher frequencies rather then motor control. If all fails I will use two signal generators with delayed pulse output for both driver (TC4420 and TC4429). Ideally the correct signal would be perfect. Any advice?
     
  2. shortbus

    AAC Fanatic!

    Sep 30, 2009
    4,019
    1,542
    Don't quite understand your question? If your using a signal generator, why are you also using a comparator and optocoupler? And where does the LSTTL output come in to play?

    The IRS21844 is LSTTL compatible so that is answered. The nice thing about the IRF drivers like the IRS21844 is they don't need a optocoupler if the mosfet voltage is under the 600V rating for the driver. What about the "boot strap" circuit for the high side switch? Do you have one?

    A driver like the IRS21834, will also give you the benefit of only needing one input for both the inverting and non-inverting switching, and "dead timing" so high and low switches won't be on at the same time.

    A schematic of what your trying to do will get you better and more answers.
     
    timlauer01 likes this.
  3. timlauer01

    Thread Starter New Member

    Nov 22, 2012
    2
    0
    My signal generator with CMOS and TTL output seams not directly be able to drive the half bridge driver. I simulated it for my viewers with two independent input sources where I could change the pulse width and timing between high and low side. Using TC4420 and TC4429. I will buy some of these chips and try again. Thanks.
     
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