I am looking for economical ready-made MOSFET modules that can be properly driven by a 3.3V PWM pin. I dont think I care if P or N type.
I want to be able to drive strings (say 5/6) of LEDs up to long 12V strips of LEDs but would be happy with a maximum current of 1A. Opto-isolation would be nice to have.
I see lots available and many claim to be driven by 3.3V but then you read reviews that say 3.3V does not trigger heaver loads properly.
What products have people found to work reliably at 3.3V? Please don't guess, I am looking for recommendations based on actual positive experience.
I don't mind if they are singles, 2, 3 or 4 channel modules but don't want to have to add 3.3 to 5V converters. Not looking for relays as I am producing lighting effects that call for dimming.
I am based in the USA but am happy to order direct from China for price advantage.
Edit: other solutions (such as constant current regulators) that would do the job are also OK
I'm just learning MOSFETS but I think they have a 4.5V or 10V trigger threshold. I'd use a 5V module and stick a logic level converter in front of it, or you can make a logic-level converter from an N-MOS:
I think that's right.
In this case the 5V_D_Pin would be the module and the 3.3V_D_Pin would be your 3.3V PWM pin.
and yes there are MOSFETS with lower trigger voltages (I have built such circuits) and as I said I do not want to use converters and I need to use 3.3 V
I understand that you don't want to add level converters, but
this module has an opto-coupler to isolate the power part of the arduino and nothing needs to be added to your circuit
right, I ordered three like that in September and they arrived yesterday. All three don't work at all, even with 11V on input. Different seller, who may just be selling rejects.
Hi @DaleSchultz
You can post pictures of those who purchased top and bottom views.
over the top so I can identify which opto coupler and which MOSFET is being used?
Hi @DaleSchultz
This is the schematic of your module.
Which board (arduino or other controller) are you using to control the MOSFET?
Can you post a schematic of your project?
Probably if using 3.3V, the 1K resistor R1 should be modified and LED1 short-circuited.
EL817 V Typical Forward = 1.4V
Typical LED1 V Forward 1.4 V.
EL817 Forward current IF 60 ma.
3.3V -1.4v - 1.4V = 0.5V
0.5V /1K = 0.5 mA --- >> Not enough to light the LED on the
EL 817.
Short circuiting LED1
3.3V -1.4v = 1.9V
1.9V /1K = 19 mA --- >> It may be enough to light the LED of the EL 817.
We can exclude anything to do with the processor and its pins, I applied 11V to the trigger connections and the outputs still produced nothing. Same LED and resistor works fine when connected to the main power supply connectors and trigger connections.
When looking at another wiring schematic I also wondered about shorting out a resistor and LED to improve signal.
I am trying to find modules that work off the shelf so I can recommend them to people using my stuff hence my endeavor to find a working one that people can just buy with confidence.
I tested that the LED and 1k resistor works by applying voltage between the + driver and the pin of the optocoupler. But they never light up with the proper ground pin.
