Original fets were FQP34N20
- 200V
- 31A
- 2370 input capacitance
- 75milliOhm RDS
I replaced them with IRFB31N20D.
- 200V
- 31A
- 2400 input capacitance
- 82milliOhm RDS
Gate resistors are 47ohm.
Attached is a photo of the switching wave of the output fets. There are 2 banks with 4 mosfets in each bank.
Right now I put one mosfet in each bank to test.
The fets heat up a little bit. The switching of the fets looks good? Or do I miss something here 😀
- 200V
- 31A
- 2370 input capacitance
- 75milliOhm RDS
I replaced them with IRFB31N20D.
- 200V
- 31A
- 2400 input capacitance
- 82milliOhm RDS
Gate resistors are 47ohm.
Attached is a photo of the switching wave of the output fets. There are 2 banks with 4 mosfets in each bank.
Right now I put one mosfet in each bank to test.
The fets heat up a little bit. The switching of the fets looks good? Or do I miss something here 😀
Attachments
For me is ok, but, try connecting a 1uf 250V film cap between negative and positive rails as close as possible to the mosfets.
You should sort the little spike.
You should sort the little spike.
Thanks Mario ^^
I have put these in my shopping cart and try them out as soon as I got them in house.
Is it a problem/normal for output fets to run a little bit hot on idle?
Especially when putting only one fet per bank?
I have put these in my shopping cart and try them out as soon as I got them in house.
Is it a problem/normal for output fets to run a little bit hot on idle?
Especially when putting only one fet per bank?
Not supposed to get warm? Are you testing with no load?
Is this a switching amplifier (class-D)? Or is that wave form a square wave output? Voltage rails? What is switching frequency?
You will have switching losses, which is heat, but the driver should also get a little warm...
Is this a switching amplifier (class-D)? Or is that wave form a square wave output? Voltage rails? What is switching frequency?
You will have switching losses, which is heat, but the driver should also get a little warm...
Post a photo of the amp board.
The outputs in some class D amps run hot, likely due to too little deadtime.
I found it very difficult to predict what outputs would be good substitutes by looking at the specs.
The outputs in some class D amps run hot, likely due to too little deadtime.
I found it very difficult to predict what outputs would be good substitutes by looking at the specs.
Amp runs fine. Installing all the output fets made the little spike dissapear.
Fets run cool and happy.
Thanks guys ��
Fets run cool and happy.
Thanks guys ��