Here's an interesting circuit problem, make a precision 1.5kV 1500V/us ramp, good to 1%.
It features a HV MOSFET current source with a feedback circuit to maintain a constant output slew rate. Related to the thread, "op-amp-controlled MOSFET cucrrent-source", the circuit uses a BUF634 gate driver, but without any "R2 C2" loop feedback elements.