Topology Federmann, HQQF-55 ...

[Ultima Thule]

Originally Posted by cbdb

I took intrinsic to mean part of the FET structure (like in a JFET (drain or source to gate)), not added on. Your not actually blowing the fet but the diode.

[cbdb]

Thanks I did not know that (but only Power Mosfets, right).

[Ultima Thule]

Originally Posted by stinius

Chris

If you look at the schematics in post #1 you will see both N and P devices.
I think he explained somewhere that it was the program he used that did the mistake.

Anyway I’m concerned about the lack of a lot of resistors in the OP stage, so if Federmann could contribute about that it would be nice.

How is the weather in Canada? Here in Norway it’s soon winter.


Cheers
Stinius

It's true, Federmann changed the drawing in post #1, magnify his picture and we can see the schematics is done on 3rd of November while the post/thread started on 29th of September. PMA has the initial drawing that dates back in early September: Topology Federmann, HQQF-55 ...

We had snow here in Finland for some days ago but it's gone for now, colder than normally for the season and also my friends in Beijing reported snow already, hopefully we will get a white Christmas this year!

Cheers Michael

[anatech]

Hi Michael,
In that case, stay warm!

If it's too cold to go out, design and build something!

-Chris

[Federmann]

Originally Posted by Ultima Thule

It's true, Federmann changed the drawing in post #1, magnify his picture and we can see the schematics is done on 3rd of November while the post/thread started on 29th of September. PMA has the initial drawing that dates back in early September: Topology Federmann, HQQF-55 ...

I changed the scheme to be correct, that some confused. There is an old scheme in MC.

[PMA]

Regardless your usual manipulation with drawings, which is not so important now, please answer the technical questions :

1. Have you already tested that your output stage with paralelled Mosfets, the circuit that does not use individual gate stoppers and that does not use individual source resistors would work, and would give the declared 2 x 500W?

2. You say you care about linearity of your input stage. Have you made any distortion simulations supporting your statement? We have already seen a sort of Bode plots.

[Upupa Epops]

I had build many types mosfet amps, with lateral and vertical types...I can to predict results...but maybe my way was not fifty ears correct...

[Federmann]

Originally Posted by PMA

Regardless your usual manipulation with drawings, which is not so important now, please answer the technical questions :

1. Have you already tested that your output stage with paralelled Mosfets, the circuit that does not use individual gate stoppers and that does not use individual source resistors would work, ….

I long ago wrote that it is the same as BUZ906X4S, also has no emitter resistors and it works.

[PMA]

The Magnatec part shares same package and transistors are certainly made from the same piece of silicon. Do you expect the IRFP240 and IRFP9240 to have the same level of matching? Have you tried to operate them without source resistors?

[PMA]

I have a stock of some 150 + 150 2SK413/2SJ118 Hitachi MOSFET devices. It is impossible to find just pair of completely matched devices of the same type (let's speak only about 2SK413 for example). The IRFP device would be the same. Omitting source resistors means very different power load to individual transistors. This would result both in poor reliability and poor linearity.