I need to drive a MOSFET (IRFZ44N) with a microcontroller (dsPIC33FJ64MC202). The problem is, the PIC runs at 3.3V and the FET's Vgs(th) lies between 2V and 4V, so there will be times my PIC won't turn it on. But, the PIC has some 5V tolerant pins. How can I use them?
The datasheet says:
Up to 5.5V output with open drain configuration on 5V tolerant pins with external pull-up.
11.2 Open-Drain Configuration
In addition to the PORT, LAT and TRIS registers for data control, some port pins can also be individually configured for either digital or open-drain output. This is controlled by the Open-Drain Control register, ODCx, associated with each port. Setting any of the bits configures the corresponding pin to act as an open-drain output. The open-drain feature allows the generation of outputs higher than VDD (e.g., 5V) on any desired 5V tolerant pins by using external pull-up resistors. The maximum open-drain voltage allowed is the same as the maximum VIH specification.
It seems so obvious but I still don't get it... How do I wire this circuit? What code do I need to make this work?
Note: I can't change either of those components. That's what I've got to work with.