p-channel MOSFET switch

Components & Accessories Power
1

I want to use a MOSFET as a switch driven by my microcomputer.

aqDwX.png842×599 6.45 KB
https://i.stack.imgur.com/aqDwX.png

The original circuit using N-channel MOSFET is on the left side. Honestly, I do not understand the choice of the IRLZ44. The circuit is designed for Arduino, which has 5V logic. Which means that for GPIO=True=5V, MOSFET opens and lets the current into the load.

However I have two problems:

I am using Raspberry Pi, which has 3.3V logic. According to available information, 3.3V is not enough to fully open MOSFET.

I want my load to be connected to the ground (I had to do some voltage measurements).

I know enough electronics to assume that using P-channel MOSFET, as shown on the right side, might solve both of my problems at one stroke. For GPIO=False=0V MOSFET will be fully open, while GPIO=True=3.3V puts -1.7V on the MOSFET gate and practically close it down. If that does not suffice, I could also put GPIO into the listening mode and therefore pull the MOSFET gate to 5V.

Could you please tell me if the idea will work? And what IRLZ44-equivalent [ P-channel MOSFET should I use?](https://www.kynix.com/Blog/The-Best-Tutorial-for-P-Channel-MOSFET.html)

2

According to available information, 3.3V is not enough to fully open MOSFET.

For practical applications, that depends on the load.

The IRLZ44 will typically conduct 2 Amperes with 2.3V on the gate. There are other logic level, N-channel MOSFETS that are fully on with lower gate voltages, and Sparkfun sells a couple of examples.

What, exactly, is the load?