The Vgs limit is +-20V and Vds is -30V. The datasheet of the PMOS is in the attachment, i hope it helps get closer to a solution.perhaps you exceeded the Vgs, or the Vds of the mosfet, perhaps you static damaged it ? there are a myriad ways you could have ruined it - over zealous with a soldering iron ... the list goes on ...
Drain Current-Continuous is -4.3A, Yes i agree with you on the reliable power electronics design and learning part.the Id max could be too small for the inrush current and you turned it into a resistor - there are many things to consider for a properly reliable power electronics design .... as you are finding out - slowly ....
Yes, i could use a parallel but then i would have to change the fuse right ?hi nishant,
The internal diode is under rated for your application.
You could consider a parallel shottky diode.
Okay i see!! fuse is just for battery protection and series diode or parallel diode or P MOS is for the project circuit ? If i understand correctly?hi,
You have to decide under what conditions do you want the fuse to blow.?
By the time it has blown , some other part of the circuit that is causing the high current will be damaged.
So what is the fuse protecting.? usually the power source , not the project circuit.
You could use a higher power P MOS.
Oh but if there's no current to the project in case of reverse polarity then why are my ICs getting blown?hi,
Okay i see!! fuse is just for battery protection and series diode or parallel diode or P MOS is for the project circuit ? If i understand correctly?
The PMOS is for power supply reverse polarity protection only, if incorrect polarity then the PMOS is not conducting, no current to the project.
The PMOS internal diode is forward biassed, if the polarity is correct, so current will flow into the project circuitry, via the diode.
Most likely cause is that the internal diode had blown short circuit due to excess high current when the polarity was correct.! The internal diode is unrated for the project current.
added: being a short circuit it would not give reverse protection
In the dead one, the measured resistance between gate and source is 12.1Ω, whereas in the new one (unused) it's 9.1 MΩ
And then the PMOS conducts as gate more -ve than source, although its 'upside-down' it still conducts well enough to reduce the voltage drop to a few mV and the losses to a few tens of mW (here approx 120mW) compared to a diode alone (approx 2W). When I first saw a PMOS used backwards like this I couldn't see the point - why just not use a diode? But then I found an article from Infineon explaining why/how and it all made sense. But you do need a device big enough to cope... most TO220 devices with no heatsink will handle 2W easily, so 120mW is a non-issue. But SMD parts need a little more thought.The PMOS internal diode is forward biassed, if the polarity is correct, so current will flow into the project circuitry, via the diode.
|Thread starter||Similar threads||Forum||Replies||Date|
|D||Can someone help me on this simple circuit. please ?||General Electronics Chat||7|
|S||Can someone help me please!!!? IRFZ44n MOSFET heats up driving TEC Peltier||Microcontrollers||13|
|Z||Could someone please help me with (choosing a radio receiver)||Wireless & RF Design||2|
|Can someone please help me identify this LED of my TV?||Datasheets, Manuals & Parts Identification||0|
|B||Can someone help me with the identification of a component please.||Datasheets, Manuals & Parts Identification||7|
|Can someone help me on this simple circuit. please ?|
|Can someone help me please!!!? IRFZ44n MOSFET heats up driving TEC Peltier|
|Could someone please help me with (choosing a radio receiver)|
|Can someone please help me identify this LED of my TV?|
|Can someone help me with the identification of a component please.|
by Aaron Carman
by Jake Hertz
by Aaron Carman
by Jeff Child