Yep, I'm still working on that flyback project..
I settled on using a 555 timer to drive the flyback, as a ZVS driver will destroy my rectified flyback.
My problem here is that in order to fire the MOSFET, the grounds of the 12 volt supply (To the 555) and the DC output of my variac (The voltage that is actually driving the flyback) have to be common. This introduces another problem though: the drive voltage cannot exceed the Vgs limit (30 volts in this case) of the MOSFET, which is incredibly low on most MOSFETS (Care to show me any that have higher Vgs limits?).
I heard that you can use two Zener Diodes, with the cathodes paired, between the gate and source of the MOSFET, to shunt excess voltage. I need to know if this will work, and, are there Zener Diodes that can handle what I am trying to use them for?
I settled on using a 555 timer to drive the flyback, as a ZVS driver will destroy my rectified flyback.
My problem here is that in order to fire the MOSFET, the grounds of the 12 volt supply (To the 555) and the DC output of my variac (The voltage that is actually driving the flyback) have to be common. This introduces another problem though: the drive voltage cannot exceed the Vgs limit (30 volts in this case) of the MOSFET, which is incredibly low on most MOSFETS (Care to show me any that have higher Vgs limits?).
I heard that you can use two Zener Diodes, with the cathodes paired, between the gate and source of the MOSFET, to shunt excess voltage. I need to know if this will work, and, are there Zener Diodes that can handle what I am trying to use them for?