[SOLVED] P-mosfet driving a load

[jameslee]

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.

 

[alexan_e]

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

 

[jameslee]

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?

 

[alexan_e]

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

 

[jameslee]

Thanks Alexan, I miss out that parameter in datasheet