600W Class D amp

[luka]

you are damn close to VDS (Avalanche), which you don't want to reach

 

[manojtm]

you are damn close to VDS (Avalanche)

Hi,

Yes.

VDS max 200 V
VDS (Avalanche) typ. 240 V
RDS(ON) typ. @ 10V 21 m ohm
***Safe run VDS= +/-80V go up to +/-90v(for class D)***
for High volt application use 500v MOSFET

Regards
MANOJ

 

[manojtm]

Hi

Use IRFP23N50L for up to +/-150v class D design

Regards
MANOJ

 

[badboy6120]

Hi

Use IRFP23N50L for up to +/-150v class D design

Regards
MANOJ

Isn't the RDS on way high on this one??

and also what will happen if I use IXFK64N50P with 9700 nF input capacitance? I test it with 1000W rms and with current schematic and there was no problem

 

[badboy6120]

Hi

Use IRFP23N50L for up to +/-150v class D design

Regards
MANOJ

Also
How about IRFP460 or IRFP470??

 

[badboy6120]

Hey guys
Can chaging mosfet increase the freqency?
tthe last time I measure the frequency with IRFP4227 and it was about 250Khz but now with IXFK64N50P the frequncy is about 400Khz!!??

 

[MorbidFractal]

Yes. It is a self oscillating design. The nominal operating frequency is set by cumulative phase shifts and time delays through the circuit. Guess that it is the difference between Crss in the mosfets. Reverse transfer capacitance also known as Miller Capacitance giving rise to the Miller Effect. Bigger values result in slower turn on... read as greater turn on delay giving lower frequency operation.

 

[manojtm]

now with IXFK64N50P the frequncy is about 400Khz!!??

Hi,

Gate resistor value=???

Regards
MANOJ

 

[badboy6120]

Hi,

Gate resistor value=???

Regards
MANOJ

Hello sir manoj
seems like I made a mistake in reading and the frequency was the same

so is there a problem with using this mosfet with this much input capacitance?
could it damage the IR driver chip
or should I replace it with IRFP460 or even IRFP470???

 

[manojtm]

Hi,

use STW56N60 for very high volt(+/-180v) and use for below +/-150v FDA59N30 OR IRF300P227

so is there a problem with using this mosfet with this much input capacitance?

Yes, use RG=4.7 ohm ~ 15ohm Or use totem pole to drive MOSFET and set fsw to 250KHz

Regards
MANOJ

 

[badboy6120]

Hi,

use STW56N60 for very high volt(+/-180v) and use for below +/-150v FDA59N30 OR IRF300P227

Yes, use RG=4.7 ohm ~ 15ohm Or use totem pole to drive MOSFET and set fsw to 250KHz

Regards
MANOJ

I only could find FDA59N30 here and I think all of its specs are good except for its turn on @ off delay:
Td on = 290 ns
Tr = 1.16 us
Td off = 250 ns
Tf = 410 ns

If I could solve my problem on IXFK64N50P with only changing the gate resistor, I'll would rather use that one because it's much faster mosfet
what do you think?

Thank you again for all your help

 

[badboy6120]

Here's a list of my options if those aren't good:
APT5020BVR
IPW60R160C6
IRFP470
IRFPS40N50L
K39N60W
SPW47N60C3
FDA59N30

 

[badboy6120]

Also
IXFX32N50
IRFP264N

 

[badboy6120]

Sir monaj
Isn't this amp with your power supply short circuit protected? because as I decrease the load impedance to 2 ohms at high power the protection kicked in but when I shorted the output, the mosfets failed
I'm using Irfp4229

 

[manojtm]

Isn't this amp with your power supply short circuit protected?

Hi,

still now i could not provide short circuit protect,if you manage to drive 8R load with below 60v rail OC=11A peak OC= 18A may be it will work.{ may work some times may not}

Regards
MANOJ

 

[badboy6120]

Hi,

still now i could not provide short circuit protect,if you manage to drive 8R load with below 60v rail OC=11A peak OC= 18A may be it will work.{ may work some times may not}

Regards
MANOJ

thanks for your answer
I build my own version of short circuit protection and it's working pretty damn good

as I mentioned before I'm having a slight noise (hiss on twitter and a bit buzz on my midranges) on my amp output
is there any way to put amp into standby (no switching)if there is no signal in input, just like when I fire up amp for first time without any input?? as my speaker are dead silence there