[SOLVED] P-mosfet driving a load

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jameslee

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Hi guys, i have one question in mind regarding P-mosfet,

I want to provide reverse polarity of input supply such as the simply schematic i attached.
However the datasheet usually specified Id current that is flowing from source to drain.
But my case is from drain to source instead. I did experiment on a breadboard and it work to provide reverse polarity of input supply, but my worry is whether it can carry high current without damage.

:smile: the question in my mind is, does P-mosfet able to carry the same maximum current(0.75A @ 25C) in reverse direction?
Thanks in advance.
 

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When the drain has a higher voltage compared to the source then the internal diode of the mosfet is constantly on and the current flows through it, you can't use it this way.

Alex
 

Yes indeed, it is meant to be on all time when the polarity of Vin is correct, and off when Vin is reversed.

But if i operate the mosfet in this fashion, can it still take 0.75A?
 

The parameter is described in the datasheet in the REVERSE DIODE LIMITING VALUES AND CHARACTERISTICS section

IDR Continuous reverse drain current Ta = 25 ˚C -0.75A
 
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Thanks Alexan, I miss out that parameter in datasheet
 

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