[Argus25]

Here is something that is very helpful in designing a flyback converter.

If the feedback which generates and sustains the oscillations originates from the transformer itself, it solves the problem of the inefficiencies that occur when the rate of change of current with time becomes non-linear and tapers off. Since the induced voltage is proportional to the rate of change of current, the feedback simply falls away as the rate of rise of current becomes non linear, and then as that happens the feedback voltage drops suddenly and abruptly cuts off the transistor.

So the circuit automatically adjusts itself to suit the inductance properties of the transformer and you don't have to worry about the transistor being turned on for too long by the driver circuit, plus it gets rid of a driver transistor. And on top of that, the circuit is intrinsically short circuit proof.

Flyback supplies are used in aircraft exciters, to get the voltage up enough to strike a GDT. Typical circuit attached.