IRF3708 mosfet - gate resistor
Posted: Mon Nov 26, 2018 10:13 amHey there,
I want to drive some mid power 24V LED modules from my ESP8266. In order to use PWM dimming I want to use an IRF3708 mosfet without a separate driver from a gpio pin.
Now the question that pops up every time when some noob wants to use a mosfet. Do I need a resistor at the gate?
I understand that gate resistors are used to limit the current coming from a microcontroller (hence protecting the microcontroller frome conducting too much current) when charging the gate capacity of a mosfet.
So the esp gpios are ratet 12mA, So 3.3V x 0.012A makes 270 Ohm. That value is needed to ensure that the current will not exceed 12mA.
But I also read that using a gate rather high value capacitor (on most 5V controllers only 100Ohm are used) will make the mosfet 'slower', because it will take more time to charge the capacity. And I also read, that some Microcontrollers already have some form of current limitation build-in, is this the case with esp8266?
So, what should I do?
I want to drive some mid power 24V LED modules from my ESP8266. In order to use PWM dimming I want to use an IRF3708 mosfet without a separate driver from a gpio pin.
Now the question that pops up every time when some noob wants to use a mosfet. Do I need a resistor at the gate?
I understand that gate resistors are used to limit the current coming from a microcontroller (hence protecting the microcontroller frome conducting too much current) when charging the gate capacity of a mosfet.
So the esp gpios are ratet 12mA, So 3.3V x 0.012A makes 270 Ohm. That value is needed to ensure that the current will not exceed 12mA.
But I also read that using a gate rather high value capacitor (on most 5V controllers only 100Ohm are used) will make the mosfet 'slower', because it will take more time to charge the capacity. And I also read, that some Microcontrollers already have some form of current limitation build-in, is this the case with esp8266?
So, what should I do?