i'm on a project where it would be very useful to control when sensors and actuators which works at 3v3 are ON/OFF, the idea to use of this is to make it possibly to control remotely. For example my idea is to control the gate of a MOSFET at 3v3 and let the other 3v3 source coming from a regulator, feed the sensors/actuator i need to.
My question: Is it possible to do? Which ones are the best MOSFET options to do this or where i can look correctly to choose the best ones?
The idea comes from a 3v3 to 5v level shifter, but i want to just control 3v3 to 3v3. And also thought it could be okay to do with relays controlled 3v3 and feeded 5v, but looking for better options.
Can you work with surface mount, or SMD parts on thru adapters?
Look at
DMP2045UQ-7, P-MOSFET, ~0.05 ohm on resistance
and FDN327N, N-MOSFET
This circuit allows a High signal to turn a 3.3V Source on and off to other devices.
(The 3V3_EN_LOW was just a signal name added to aid in manual routing, vs an autogenerated name like N$27)
Yep, the project will based on SMD, Surface Components mostly so i will be able to use them. I'm still learning on electronic designs, so to confirm my thoughts, the FDN327N will be able to drive the gate of the DMP, and the DMP2045UQ-7 will support up to a drain current of 3~4 A depending on gate voltage right? Still missing the 100K resistor function.
Btw, really thanks for the response it will really help me to continue to develop more ideas to implement for the project :D.
The 100K keeps the FDN327 off when the line is not driven, or when the IO lines are indeterminate, such as a '328P or 2560 when it is in reset state and IO lines become Input lines.
You may have to hunt around for a similar P-channel MOSFET, DMP2045UQ-7 is out of stock at many distributors at the moment.
Yep DMP looks out stock in many places, i will try to investigate viable options and will put a list here tomorrow for someone who is interested on this too and can confirm if its nice for the application.
And about the 100K resistor, i wouldn't get it on my own that's a 'smart' way to protect on indeterminated IO lines.
This last one is the one i liked more just simply because is recommended for power applications, but the world of electronic components is so wide. So if i can get a clue if some of these are valids options would we awesome as a substitute of DMP2045UQ-7, and i saw in mouser that FDN327N will go out of stock soon :///.
Some of those look good.
I would not select Si2347 or PMV100, they do not turn on full at lower gate levels (Vgs).
I would select MCH3383 last as it appears to have a higher Rds.
Hmmm that's true MCH3383 have up to 250~500mohs at very low Vgs, and Si2347 or PMV100 looks like only turn on full starting at 5V. I will keep looking with that caracteristics.
@CrossRoads i know the post was kinda solved, but i was thinking today about the MOSFET driver in this case. Isn't the P-Mosfet able to turn of with just the microcontroller signal? I think i'm just missing something.
But wasn't both at the same level? I mean if i use alone the P-Mosfet sourcing the gate with 3.3v from the MCU i wouldn't be able to do drive it right? I think im getting confused about the High signal vs Low signal.
3V3-EN-LOW could be driven low by a microprocessor pin to turn the P-MOSFET on and allow several amps of 3V3 current to flow out to SWITCH-3V3. The 1K pullup resistor might be changed to 5K so the micro doesn't need 3.3mA to turn the P-mosfet on, 3.3V/5000 ohm = 0.66mA.
Or:
ENABLE-HIGH could be driven high by a microprocessor pin to turn the P-MOSFET on and allow several amps of 3V3 current to flow out to SWITCH-3V3.
Ohhhh, now i understand the LOW ENABLE (Tag) u put in the scheme which was confusing me a little bit (totally my fault).
So the 3V3-EN-LOW works as (inverse logic switch) if i put high on it i get low on P-MOSFET and if i put low on it i get high on P-MOSFET. And the E-High is just simple as it is.
And more about the circuit, i think i have to avoid to put both pins into the MCU right? because if i put 3v3-en-low to low and 3v3-en-high to high, both are trying to make to put the P-MOSFET to give 3v3.
So N-Mosfet in this case its just for only to give the possibility to drive the P-MOSFET with high and low signals right?.
so I can't take any credit for it.