HIGH Current H-bridge

Discussion in 'The Projects Forum' started by Ashkar, May 2, 2011.

Is this Circuit a good Design.

  1. Yes

    0 vote(s)
    0.0%
  2. No

    0 vote(s)
    0.0%
  3. IMPROVEMENT REQUIRED------LIST THEM

    100.0%
Multiple votes are allowed.
  1. Ashkar

    Thread Starter Member

    Feb 7, 2011
    71
    0
    Hi,
    I am planning to build a 150amp 12v N-Channel H-Bridge controller by using irfz44n mosfets.so Please help me.i dont want to use market ics to drive high and low side.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Those are only 49 amp FETs. Why do you want to avoid driver IC's?
     
  3. retched

    AAC Fanatic!

    Dec 5, 2009
    5,201
    312
    I think it has something to do with self-torture, because those little driver ICs's make this a SIMPLE task.

    Many dont require any support components. You only need the driver and the FET.
     
  4. ifixit

    Distinguished Member

    Nov 20, 2008
    639
    108
    What supply voltages are available besides 12V?
     
  5. Ashkar

    Thread Starter Member

    Feb 7, 2011
    71
    0
    Thank you all for you replay.
    I always like to create my own circuit,I am into self Developing type so,I would like to parallel irfz44n mosfet for high current since i want to drive a motor into both direction and control its speed using pwm circuit.
    I only have 12v to drive my motor but i would make a separate power supply for logic circuit.i.e only 12v power for my motors and separate power supply for logic circuit if needed.
     
    Last edited: May 11, 2011
  6. Ashkar

    Thread Starter Member

    Feb 7, 2011
    71
    0
    Please Reply soon......
     
  7. ifixit

    Distinguished Member

    Nov 20, 2008
    639
    108
    Do you have any p-ch mosfets to use for the high side? Without special circuits you don't have enough voltage to turn on high side n-ch mosfets.

    Sounds like you need 3 or 4 mosfets in parallel, thats 16 mosfets, do you have that many?
     
  8. Ashkar

    Thread Starter Member

    Feb 7, 2011
    71
    0
    I Got 25 Of them ,so I am emphasizing to go with the N-Channel Type ,Please direct me how to built it.
    I am using this circuit with a IC555 for PWM Purpose and allow it to work in 3 way(CCW CW And stop)
     
  9. Ashkar

    Thread Starter Member

    Feb 7, 2011
    71
    0
  10. Ashkar

    Thread Starter Member

    Feb 7, 2011
    71
    0
    what changes and circuit do i have to implement in the above circuit.
     
  11. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,670
    804
    What frequency do you expect your pwm to be?
    You will need some kind of SMPS or charge pump to get enough voltage to drive the upper FETs. Also some current sharing resistors in series with the FETs wouldn´t hurt.
     
  12. Ashkar

    Thread Starter Member

    Feb 7, 2011
    71
    0
    thanks for your valuable suggestions ,I would be using frequency of about >3kHz,please guide me how to built this type of H-bridge.
    reply soon..
     
    Last edited: May 5, 2011
  13. Ashkar

    Thread Starter Member

    Feb 7, 2011
    71
    0
    Last edited: May 5, 2011
  14. retched

    AAC Fanatic!

    Dec 5, 2009
    5,201
    312
    No. it has only 100ma of output current. This is no-where near enough current to switch the 16 MOSFETS fast enough.

    The MOSFETs will spend most of their time in their triode region, producing heat.

    Even if you used 1 on each MOSFET, it would not switch fast enough to keep them from destroying eachother.

    You need to switch the MOSFETs in the tens of nanoseconds (or less) when you are dealing with that much current.

    ALSO, the more current you can supply to the MOSFET gate, the faster they switch out of the triode region and into saturation.

    Saturation is where the MOSFET is at its lowest resistance point (between source and drain) The lower the resistance, the lower the temperature.

    MOSFET gate drivers are so cheap these days, that you would be doing yourself a disservice by not using them.

    Find a friend who will mail them to you. This is the internet for goodness sake.. You can find someone to help. Also, there are companies that do ship internationally.

    Take a look around. Many drivers support more than 1 MOSFET per chip.

    I use a lot of Claire drivers. They have built in opto-isolation that helps reduce space needed and part count.

    http://www.clare.com/Products/MOSFET.htm
     
  15. Ashkar

    Thread Starter Member

    Feb 7, 2011
    71
    0
    thanks a lot
     
  16. retched

    AAC Fanatic!

    Dec 5, 2009
    5,201
    312
    Just to add to what I was saying, without making the wall-of-text bigger.

    Here is an APP-NOTE that will explain what I was talking about.

    It has schematics for MANY different gate drivers. SO if you cannot get an IC, you can build your own.

    I reccomend reading the ENTIRE paper. It will educate you about the inner workings and the WHY behind it.

    It will also teach you how to build the drivers and WHY they function the way they do.
     
  17. Ashkar

    Thread Starter Member

    Feb 7, 2011
    71
    0
    Please suggest any other charge pump for high side
     
  18. Ashkar

    Thread Starter Member

    Feb 7, 2011
    71
    0
    please help me to calculate the heatsink counter part for 16 mosfets
     
  19. retched

    AAC Fanatic!

    Dec 5, 2009
    5,201
    312
    Do you have the data sheet for your MOSFETs?
     
  20. Ashkar

    Thread Starter Member

    Feb 7, 2011
    71
    0
Loading...