The main simplification was using a constant PWM signal. The result is that ... Here’s an online simulation of the circuit. If you probe the output of U1 you’ll see a nice square wave.

Of course, the inductor and capacitor also form a resonant circuit which can interact with the PWM frequency, but for now, I am literally just “junk boxing” the circuit so we’ll skip the math.

This design idea reprises another “1A, 20V, PWM controlled current source.” Like the earlier circuit, this design integrates an LM3x7 adjustable regulator with a PWM DAC to make a programmable 20 V, 1 ...