How can I make a circuit that outputs a negative voltage of -12V if I input a positive voltage?
I don't have a part called LM2575-12BT here, can you recommend it as one of the parts on mouser.kr ?
I've seen but never used those parts made to look like 7812 but with switcher guts in the classic TO-220 form. Seems to me that an inverting version of those could be made same-same. Whether the vendor or the market ever saw traction, no idea.
The full data sheet covers this quite well - how to organise the feedback etc - also the need for a delayed start - as the device will otherwise draw a lot of current from the source.