Help me as my Mosfet is burning!

Mosfet burning

Mosfet is burning.What can ı do?Please help me.

Re: Mosfet burning

Hi,

Try to put a reverse diode in the mosfet. It avoids the spikes of the inductive load.

Mosfet burning

Brunofunchas
please show with schematic.Because ı dont understand.
İs the diod 1N4001 or else?

Re: Mosfet burning

Q2 and Q3 should to be capable of switching at least 1A of current, so using BC547/557 is out of question ..
Instead, try BD135/136, BC639/640 , ZTXnnn/yyy and so on ..

This MOSFET has built-in "body diode", so just add a (kick-back)diode in parallel with the load, as shown on the attached picture ..
For 10A load I'd use a 3A diode such as 1N5404 or similar ..

IanP
:|

Mosfet burning

IANP
is the resistor of gates 10R or 10K?

Re: Mosfet burning

is the resistor of gates 10R or 10K?

Click to expand...

10R=10Ω

Re: Mosfet burning

Thanks
ı will try

Mosfet burning

The above suggestions are good. Up to medium PWM frequencies (several 10 kHz), BC5xx and 22 ohm gate resistor would be sufficient, I think. The missing free-wheeling diode is the key point, assuming the load is actually inductive, as the "L1" designator says.

Mosfet burning

Drain to Source On Resistance Rds(on)=0,017ohm
If 10 AMper; 11,7watt
May be this is a another problem?

Mosfet burning

No,no!
If you have 10 Amper (DC?) & 0,017 Ohm (17milli Ohm), than is Pd= 1,17W to calculate!
K.

Added after 11 minutes:

Heyyy! :-( :-(
I did found only IRF9540N, but PLEASE learn WRITE EXACT requirements!
Its Rdson=0.117Ohm, so it will dissipate 11.7Watt, the package has Rθja max=62Cels/Watt; pls calculate the rest...
If you dont have extra heat sink or sufficient coopers on both (or more) PCB layers = > you will kill with the produced heat (theoretically > 700 Celsius) your MOSFET...
BTW; you can select betzter FETs in same package & voltage class at i.e. ca 15 milliOhms, what means only 93Celsius plus environmet=some at assumable 150 Celsius, junction temp., but it will be usable with so such quadrate cm cooper on both PCB-sides (or a little SMD heat sink over that) ...
K.

Mosfet burning

A bit of a separate issue, but why did you use a PMOS rather than connecting the load to 12V and using an NMOS with low side switching? NMOS generally have a lower RdsON.

Keith.

Re: Mosfet burning

MOSFET is too small for the job. Use lower R-DS device and good heatsink. As it is now you can drop about 17% of your source voltage over the device so your load is only receiving 10V.