I need a switch to control the connection between a solar panel and a buck converter; for this application a MOSFET would seem to be a good choice (let me know if that is a bad assumption!).

The solar panel puts out 44V, and I hope to use a Raspberry Pi microcomputer to control the gate (the RPi can provide 5V or 3.3V). Max amps flowing through to the load, a solar fan, would be less than 4A.

I play with some electronics but am still learning...and do not confidently understand all of the spec sheets. Looking at an FQP30N06L, for example, the Absolute Maximum Rating for Gate-Source voltage is +/- 20V. Am I thinking correctly to say that I would need at least 44V - 5V = 39V, or about twice the Rating?. For an FQP27P06 that spec is +/- 25V. I attached the spec sheets for these.

Am I reading things correctly? Can someone suggest a MOSFET that would work for this situation?

Thanks for sharing your expertise!

 

Welcome to AAC.

Probably not a good idea. The N-channel versions don't generally work well between devices. P-channel may be a different story. Show us your schematic.

 

Can you switch on low side or does it have to be high side ?

Regards, Dana.

 

Can you switch on low side or does it have to be high side ?

Regards, Dana.

Thanks, Dana and jpanhalt. I am still in the process of learning more about MOSFETs and electronics in general; its an iterative process and I'm not actually able to answer your questions yet. Perhaps I have posted my question too early. In the meantime, though, I am grateful for any guidance as to whether I am reading the spec sheets correctly.

Thanks in advance.