Hi. I want to make a constant current driver for a Xenon arc lamp. It takes 12V as input, should give out 8A at 15 - 20V, and maintain 50V idle voltage. I used a TL494 to control it, single-ended output driving a boost converter. 100KHz frequency. Schematics attached below. It basically works, but there are problems. The thing surges and whines in audible range, the input is whole 20A at 12V with output at 8A at 15V, and the current is often a few A above the setting. The symptoms are here sometimes, and not here the other times - depending on the load or voltage, or just nothing specific at all. What am i doing wrong? Tried different inductors, from 10uH to 500uH, capacitors on the current feedback input, chokes - the whine changes tone, but never goes away.