Reliable and Flexible Switching System

[EMJunkie]

Fault Handling! Housekeeping! What a concept....

Nearly there TK!   

You're an Electronics GURU! Feel up to posting a Circuit with Layout?

All the Best

  Chris

[MarkE]

Nearly there TK!   

You're an Electronics GURU! Feel up to posting a Circuit with Layout?

All the Best

  Chris

The application of the circuit really needs to have parameters placed around it.  One size fits all does not work well in power electronics.

[EMJunkie]

The application of the circuit really needs to have parameters placed around it.  One size fits all does not work well in power electronics.

Hi MarkE,

Yes, I hear you and agree it will not be an easy task to achieve a "One size fits all"!

But we can get close!

The Circuit I Posted, from Selfonlypath, is that! Very Close!

All the Best

  Chris

[MarkE]

Hi MarkE,

Yes, I hear you and agree it will not be an easy task to achieve a "One size fits all"!

But we can get close!

The Circuit I Posted, from Selfonlypath, is that! Very Close!

All the Best

  Chris

Chris there are a couple of things that you should look at in your circuit.

1. Critical:  The MOSFET avalanche protection is limited to the snubber network.  With a big inductive load that will either end up dissipating a lot of power or you will blow the MOSFET.  The flyback diode anode should be on the MOSFET drain, and the cathode on +DC where it is decoupled through a long inductance back to the MOSFET source.  The size of the decoupling capacitor depends on how much inductance there is back to the +DC supply.   This is particularly true given that you have a 1 Ohm gate turn-off resistor.

2. Design Improvement:  One section of the MCP1403 should be more than adequate for each MOSFET.  If you are going to drive more than 4.5A of gate current, you will have more issues with layout than driver strength.  The only reason that I would allocate by halves of that driver to one MOSFET would be if that made a big difference in the parasitic inductance in the layout.

3. Design Improvement:  You should place a 200uF capacitor in series with a 0.5 Ohm resistor across C4.  This will keep the filter L1/C4 from resonating uncontrollably when the MOSFETs are driven near 3kHz.

4. Design Improvement:  C5 should have a 47 Ohm or so resistor in series so as to limit the peak current load on the ATMEGA.  Otherwise you can kill the output pin from electromigration.

5. Design Consideration:  Z1 will only be effective if it has a very low inductance between the MOSFET gate and source.  Also, a typical zener will not act quickly enough to protect the MOSFET gate.  A TVS device rated at 16V that will trip by 20V would be a better choice.

5. Documentation Error:  The notes say D2 is for asymmetric gate drive.  It should say D3 and R4.

[Dog-One]

Found this about a year ago and saved it:
http://www.source-for-innovations.com/pgen.htm

Gunther has put a lot of effort into this design:
http://www.source-for-innovations.com/switch.htm

I have used the circuitry myself and it works quite well.


@MarkE

Jump in here Mark, make improvements and post some EAGLE files we can use to build breakout boards.  As sharp as you are in this area it shouldn't take you more than an hour or two to get us all setup.