I was recently asked to use 2 mosfets to make a switch that turns a fan on/off via a PWM pin of an stm32 (this allows a gradual switch-on of the fan and not all at once .. here).
I cannot understand why I need two and not one mosfet.
Maybe it's because having a GPIO PWM [0 ... 3.3]V output that must drive a mosfet with Vgs(th) of 2V or more ... there is a risk of not switching the mosfet on .. and thus I need an amplification stage (to be implemented between GPIO PWM and the mosfet that switches the fan on/off).
Is this correct?
Keep in mind that I would like to use a through-hole mosfet package for better dissipation (I will mount it on a PCB) ... than perhaps other types of packages
I cannot understand why I need two and not one mosfet.
Maybe it's because having a GPIO PWM [0 ... 3.3]V output that must drive a mosfet with Vgs(th) of 2V or more ... there is a risk of not switching the mosfet on .. and thus I need an amplification stage (to be implemented between GPIO PWM and the mosfet that switches the fan on/off).
Is this correct?
Keep in mind that I would like to use a through-hole mosfet package for better dissipation (I will mount it on a PCB) ... than perhaps other types of packages