Engineering Stable Load Current and Voltage in a Simple MOSFET Driver Circuit

[Forcefedglas]

Homework Statement

Homework Equations

The Attempt at a Solution

I know what the transients should generally look like, the only part that's throwing me off is how to model the intended load voltage of 18V. I'm guessing that when the switch is on (after transients) the load voltage will be close to 48V (minus the FET voltage drop) since there's nothing in place regulating it, is it safe to assume that the load current stays at 1A in this case? And if the FET is off (after transients), the flyback diode will be forward biased and the voltage across the load will be -0.46V? If that's the case, what's the effect of the 'intended' load voltage if any?

Thanks in advance.

 

[Baluncore]

I'm guessing that when the switch is on (after transients) the load voltage will be close to 48V (minus the FET voltage drop) since there's nothing in place regulating it, is it safe to assume that the load current stays at 1A in this case?

Inductor current will remain very close to 1 amp because inductance is large and frequency is high at 1MHz.

The load current will switch between the diode and the FET. Load voltage will change between two values.
While the FET is on the load current will rise slowly, while the diode is on current will fall slowly.
Relevant equation? V_L = L · di / dt
For a stable current, I_rise must equal I_fall.

What will the duty cycle be?
What will the average voltage across the load be?