I'd like to make a 4 pin pwm fan control using 3v3 uC. Fan is 12v powered and I have a 12v to 3v3 converter to power uC (VCC gate is 3v3 uC power). I want to isolate 3v3 VCC and 12v as much as possible, but without using optocouplers, just with FETs. This fan has a PWM input that shall be used to control it's speed. I need to make some kind of "repeater" for uC 3v3 logical level PWM signal. The output level shall not exceed 5V, so I made the following schematics:
The "highlighted" part is the "repeater". My questions are:
- Is it ok to use such a repeater?
- Is it possible to simplify it, for example to make it using just one FET?