Topology Federmann, HQQF-55 ...

[Upupa Epops]

I have the same opinion, Ovidiu...any balast resistors, any gate stoppers, long traces to gates...all is the way to massive oscilations and result is obvious...

[PMA]

Originally Posted by Upupa Epops

I have the same opinion, Ovidiu...any balast resistors, any gate stoppers, long traces to gates...all is the way to massive oscilations and result is obvious...

Pavel Pavel, your English is horrible

no gate stoppers, not any gate stoppers. Yesterday you mystified anatech by exchanging ANY and NO

[Upupa Epops]

Mea culpa... I am mortified and I worm into the sewer....

[Upupa Epops]

But " Give peace a chance " - F. says, that most of us goes on wrong way, so let him show us correct one....

[Federmann]

Originally Posted by Federmann

Power MOSFET is made up of many cells (transistors), 100thousand and more. As the power MOSFET is heated by power dissipation, its RDS (on) increases. It is important to select the correct voltage MOSFET. I know that no one applied, but I do.
Have a nice day.

I know that you care, but the emitter resistors are important, where the temperature coefficient is negative. Here is a positive temperature coefficient resistors, and thermal stability will deteriorate.

[danhard]

I suggest you read this Federmann :
http://www.irf.com/technical-info/appnotes/an-1155.pdf
http://powerelectronics.com/704PET23.pdf

[PMA]

The temperature coefficient of Id becomes negative at very high currents, for operating currents it is positive.

[Upupa Epops]

As I see, F. never held vertical mosfet on his hands...amazing....

[Federmann]

Originally Posted by PMA

The temperature coefficient of Id becomes negative at very high currents, for operating currents it is positive.

[Federmann]

Originally Posted by Federmann

Transistors so selected to have the same characteristics, only those transistors can be used.
As transistors have the same characteristics, sweeping the input voltage, I reach the current limit.

I know that I did not say anything, so your decision is wrong, diodes D101 and D102 serve as current protection.

Have a beautiful night.