I found this converter-circuit on the Internet. I will use it to power an IR2153, which contains a 15,6V zener. I chose to use it because of the large losses of a resistive dropper. The unmarked voltages are unknown. Diodes- high speed (BA159, UF4007 etc.)
Very inefficiently: The 0.22uF cap and 100 ohm resistor create an RC oscillator, periodically turning on BUX85. The 4.7mH inductor smoothes out the voltage somewhat, and the zener tries to make it a regulated 15ish volts. Altogether it's an inefficient and dangerous design. Good luck getting it to pass UL.