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Topic: driving an IRF630 from Arduino digital output pin (Read 2 times) previous topic - next topic

marv

@ dc42: Thanks for your reply. That's it, with 5V the IRF630 is just ON, so I'm trying to save every mV of gate drive :-)
I am not using PWM or any fast switching. Just switching the LED array ON and OFF with seconds or minutes in between, so switching speed is not an issue here, but the 1kOhm series resistor can even go down to 470Ohms and still have the Arduino channel protected for transient currents due to the parasitic gate-drain capacitance. Of course, using a buffer IC would solve all these issues, but why complicate the circuit and
incur extra costs when this simple gate-drive works well for the current application? @all: Any comments?

dc42

Exactly. You only need to use a driver IC if you are switching the mosfet at high frequency, so for your application just drive the gate from the Arduino. That is what I do. For switching low voltages at low speeds, you can even do away with the series resistor.
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retrolefty


Exactly. You only need to use a driver IC if you are switching the mosfet at high frequency, so for your application just drive the gate from the Arduino. That is what I do. For switching low voltages at low speeds, you can even do away with the series resistor.


One might also need to use mosfet gate driver IC for high power mosfets that are switching higher current loads even at slower PWM rates. The larger mosfets have significant gate capacitance so high current drivers can help the mosfets charge and discharge the gate capacitance faster, thus keeping the switching transition time shorter, which helps with the heat/power dissapation of the mosfet. The pretty high output pin current ratings of an arduino output pin works pretty well with most mosfet switching applications, however when talking really large current switching loads using large mosfets or mosfets wired in parallel, the purpose designed gate driver IC are almost always recommended.

Lefty

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