I need to control few 5V 2-5A devices by rpi GPIOs, which has the 3.3V logic level. I come up with a simple circuit, but I'll appreciate any ideas, corrections, suggestions. The LOAD is something like a powerful LED flashlight (pure real load, without reactive elements). It won't turn on/off often (once in a few minutes), so it shouldn't be a big problem with frequencies. All LOADs have common ground wire: they are parts of one device and all connected to the ground wire and chassis.

Is the circuit correct? Is it possible to improve it? MOSFET is 100V, is there any better choice?


UPDATE After @brhans comment, I'm considering also Mosfet IRF9540 (it can work with 3A at 5V) or several FDN340P, but they are in SOT23 package (hard to assemble with my equipment). Is IRF9540 a better choice?

  • \$\begingroup\$ Do your loads need common ground or just use it. In the second case you might be able to go with low-side switches and reduce number of components. \$\endgroup\$ – Maple Jun 19 '18 at 20:57
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    \$\begingroup\$ Please ask a question so it can be answered, we don't do suggestions. Specific questions get good answers. This is a Q&A site, not a general fourm \$\endgroup\$ – Voltage Spike Jun 19 '18 at 20:58
  • \$\begingroup\$ @Maple They are physically wired, that is why I have to use P-MOSFET \$\endgroup\$ – rth Jun 19 '18 at 20:59
  • \$\begingroup\$ That may not be the best choice of MOSFET to use with a 5V supply. it really wants >6V to turn on properly (7-8V would be better). \$\endgroup\$ – brhans Jun 19 '18 at 21:18
  • \$\begingroup\$ @brhans Thank you for the comment. Very useful. Can you suggest something better? I tried to find low-threshold p-MOSFET, but all of them SOIC. :( \$\endgroup\$ – rth Jun 19 '18 at 21:23

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