HIGH Current H-bridge

Is this Circuit a good Design.

  • Yes

    Votes: 0 0.0%
  • No

    Votes: 0 0.0%

  • Total voters
    1

Thread Starter

Ashkar

Joined Feb 7, 2011
71
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.
 

retched

Joined Dec 5, 2009
5,208
Those are only 49 amp FETs. Why do you want to avoid driver IC's?
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.
 

Thread Starter

Ashkar

Joined Feb 7, 2011
71
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:

ifixit

Joined Nov 20, 2008
650
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?
 

Thread Starter

Ashkar

Joined Feb 7, 2011
71
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)
 

kubeek

Joined Sep 20, 2005
5,647
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.
 

Thread Starter

Ashkar

Joined Feb 7, 2011
71
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:

retched

Joined Dec 5, 2009
5,208
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
 

retched

Joined Dec 5, 2009
5,208
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.
 

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