I am trying to control a load switch from the GPIO pins of an STM32 which outputs 3.3V. They need to be isolated using the optocoupler shown.
The problem is that the isolated voltage supplied is 24V, but 5V maximum is needed to drive the load switch enable.
Will the voltage divider work the way I am intending to at the output? What is throwing me off is the pullup resistor in parallel. How does this look?
Lower current for little power dissipation is also of interest
My calculations so far:
Ic = (3.3V - 1.2V) / 1200ohm = 1.7mA Opto CTR = 50%, Ic = 0.85mA
This is a safety switch, high switching speeds are not necessary.