So Here is an update.
I removed all of my gate drivers and to my surprise they are NOT the issue. With them out of circuit, I still had the short between 15V and GND. After some more digging around, I found out that it was due to my buck converter.
I am using the LM2576HVSX-ADJ. I Bought it from mouser, so it must be a genuine part right?
I am using it to drive 15V. The interesting thing is that once I removed the regulator it is shorted between Pin 2 (Output) and GND. It is not shorted between Pin 1 (Input) and GND. This leads me to believe that something went wrong on the 15V rail not the input.
So here is my schematic.
This is the recommended schematic by TI. The differences I have, are the diode the inductor and the output capacitance.
Diode - My diode is a Schottkey diode I think it is fine.
Inductor - I used a 100uH ias reccomened on the diagram. In figure 31 of the data sheet, it shows that for a 100uh inductor at roughly 50V, it can supply a max current of 1.75A. I do not suspect this to be an issue.
Capacitor - O the output, my capacitor is much smaller I am using a 220uF instad of the 1000uF (for the fixed) and 2000uF for the adjustable on one diagram and 1000uF on the other diagram. however I don't think this is the cause, I shouldn't be drawing large amounts of currents for this application, since I am only driving an mcu, lcd, and the fets. Or is such a large CAP required for stability?
Another issue that I am suspecting is the layout that I have used. I placed the regulator and all other components on the bottom while placing the inductor at the top due to space issues. Could this be causing some kind of issue?
Could there be some kind of ringing when I switch the FETS that is causing an issue?
This is a really surprising issue for me. I have those cheap Chinese version of this regulator which I could unsolder and test again however I'd like to see what is the underlying issue before I blow it up again.