I wish to drive a MOSFET using a 555. I dont have a driver handy, will it be fine to use a transistor instead?
So the output of a 555, could activate a transistor(as swtich), which allows a source to drive the FET?
Electronic – 555 to drive a MOSFET
555mosfet
Related Solutions
You should use a logic level gate MOSFET, not the IRFZ44N, which is not guaranteed to work. Rds(on) is specified at Vgs = 10V not 5V. Vgs(th) is for 250uA. I think your motor needs more than 250uA. It would probably sort-of work badly if you try it.
Connection is correct, however you must put a diode across the motor to keep the MOSFET from avalanching when it turns off.
A 20K or 50K pull-down is a good idea- it keeps the transistor from turning on partially if the GPIO is high-impedance.
A series 1K to the GPIO makes it a bit more foolproof. No other parts needed.
I would use the following circuit. It cuts down on parts from the given schematic. This is probably as tight as it gets in terms of board space. R1, R2 can be as small as you care to solder.
simulate this circuit – Schematic created using CircuitLab
Related Topic
- Electronic – (schematic) Using a micro controller to drive Opto-coupler > 555 timer > MOSFET
- Electronic – 555 and transistors: using a transistor to ground the reset pin of a 555 and how to drive a MOSFET with a 555
- Electronic – 555 Timer to drive IRFP460
- Electronic – Why doesn’t the 555 + MOSFET setup drive the motor
- Electronic – Why does this Mosfet get Hot
Best Answer
The 555 output can Source or Sink 200 mA so unless you want to drive the mosfet in high frequencies it will be more than enough. A single transistor is probably going to drive the mosfet worse than the 555 itself
If you are need to use a driver between the mosfet and 555 then you are better off with a push-pull (totem pole) driver configuration that can sink/source current equally strong in order to turn on/off the mosfet quickly (again only if needed)
or even better with a dedicated mosfet driver like TC4426/27/28