IR21844 based amp?

[mbates14]

100to 150khz or so

 

[mbates14]

Well according to those schematics, your using FETs that are 4600 to 5300PF gate capacitance. (IRF4115/4227)

the IRF3415 is only 2400. So when you speak of miller charge, I have no idea what your discussing.

 

[Dimonis]

There is gate charge and miller charge , they may differ much . And total charge : for 3415 total is 200nC , for 4115 - only 120nC . Compare for yourself:

 

[Dimonis]

By using IRFB4115 at 150-200kHz , my IR2184S (soic-8) heats up to 80degree C , if I use 3415 with the total charge as twice of 4115 , I think the chip might overheat .
But you have IR21844 and it has larger Package power dissipation

 

[mbates14]

ah ok. I knew there was something I wasnt looking at. Usually when I selected MOSFETs, i always looked at the gate capacitance. Just glad now I know to look at other properties.

Anyway, I guess i will use the IRFB4115 and IRFP4227 to replace the IRF3415s in amplifiers.

 

[Dimonis]

Here some simulations made in Microcap , feel the difference :

 

[doctormord]

Very nice build!

 

[mbates14]

Ok, sorry it took so long.

I did up a quick circuit and PCB layout in eagle.

Take a look and see if its ok, or if something is majorily screwed up and needs fixed.

thanks.

P.S. This is just the oscillator/output card. The filter, power supply, etc is on the main board.

 

[mbates14]

bump