The load in this case is a resistive wire used to heat a small sample of fluid to a precise temperature. A temperature PID control loop will modulate a 128Hz PWM output to keep the temperature on target.
My isssue:
> An ESP32 has no problem switching the IRL540 MOSFET on and off by means of setting a GPIO pin to 1/0 --- this with R1 10kOhm and R2 1kOhm
> If I set the GPIO pin (12 or 13) to PWM with frequency of 128Hz, and any duty cycle is selected, the heater appears to remain fully switched on
- My suspicion is that the MOSFET is not being effectively turned off
Would an expert kindly assist me with selecting values for R1 and R2 which would reliably allow the MOSFET to function with the given load at PWM frequencies as high as 512Hz? A few lines on motivation for the values chosen would also go a long way to helping others who may have similar problems.
Many thanks.
My isssue:
> An ESP32 has no problem switching the IRL540 MOSFET on and off by means of setting a GPIO pin to 1/0 --- this with R1 10kOhm and R2 1kOhm
> If I set the GPIO pin (12 or 13) to PWM with frequency of 128Hz, and any duty cycle is selected, the heater appears to remain fully switched on
- My suspicion is that the MOSFET is not being effectively turned off
Would an expert kindly assist me with selecting values for R1 and R2 which would reliably allow the MOSFET to function with the given load at PWM frequencies as high as 512Hz? A few lines on motivation for the values chosen would also go a long way to helping others who may have similar problems.
Many thanks.