MOSFET problem

[spitso]

Hi there

I am trying to build this flyback driver to creat audio modulation **broken link removed**

The problem is that everyone is complaining about the IRF540 MOSFET getting too hot and blowing. Im pretty sure its due to the ic only putting out 200ma max to the MOSFET and the MOSFET is getting "under run" causing it to heat up and blow.

Any ideas on how to fix this?
Some ideas were putting the mosfet and heatsink in baby oil (Mineral oil with fragrence, its non-conductive and supposively can help absorb the heat)
Or
Placing two MOSFET's in parrelle to increase the current (Not sure if it will work because ic max amp out is 200ma)
or
wondering is thier any other MOSFET with fast switching, can be run off 200ma, can withstand under 50v at couple amps and back emf?

thanks

 

[Leftyretro]

Hi there

I am trying to build this flyback driver to creat audio modulation **broken link removed**

The problem is that everyone is complaining about the IRF540 MOSFET getting too hot and blowing. Im pretty sure its due to the ic only putting out 200ma max to the MOSFET and the MOSFET is getting "under run" causing it to heat up and blow.

Any ideas on how to fix this?
Some ideas were putting the mosfet and heatsink in baby oil (Mineral oil with fragrence, its non-conductive and supposively can help absorb the heat)
Or
Placing two MOSFET's in parrelle to increase the current (Not sure if it will work because ic max amp out is 200ma)
or
wondering is thier any other MOSFET with fast switching, can be run off 200ma, can withstand under 50v at couple amps and back emf?

thanks

"wondering is thier any other MOSFET with fast switching, can be run off 200ma, can withstand under 50v at couple amps and back emf?"

MOSFET don't require any current to be drawn from driving source, except a little initially to overcome the capacitance of the gate. MOSFETS are voltage operated not current operated. As long as the gate voltage is 10vdc or higher the device will be turned on as much as is possible. Heating problems can be just inadequate heat-sinking.

Lefty

 

[audioguru]

The IRF540 Mosfet is pretty old and has a high on-resistance when compared to more modern Mosfets.
Use a better Mosfet like an IRFZ44 that has an on-resistance that is more than 15 times lower.

 

[Analog]

Go to digikey and use the parametric search to find a lower Rds MOSFET.