Power MOSFET Circuit Help

What is the purpose of using a power MOSFET in the main voltage input of a circuit? Why not just directly connect the main voltage input to a power supply? Why go through the MOSFET?

I am trying to understand a circuit that goes directly from a 12V battery to Drain of a P-channel power MOSFET. The Gate is connected to ground through a 1MOhm resistor and connected to Source through a Zener diode. The circuit is connected to the Source pin.

Reply to
eeboarder
Loading thread data ...

Accidentally reverse the battery. Repeat your circuit analysis. Illumination should follow.

--
Rob Gaddi, Highland Technology
Email address is currently out of order
Reply to
Rob Gaddi

That is a protection against the battery reversal. Mosfet has less of the voltage drop compared to a diode.

Vladimir Vassilevsky DSP and Mixed Signal Design Consultant

formatting link

Reply to
Vladimir Vassilevsky

And when analyzing, remember the 'parasitic' drain-source diode inside the MOSFET - it is an essential part of the trick...

Arie

Reply to
Arie de Muynck

battery

diode.

the

the

Thanks again for the help!

Reply to
eeboarder

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.