I recently bought the S18V20AHV regulator, visible here. I used it to generate a 24V output given a 12V 2.1 A regulated input. The 24V would then go to a H bridge that would drive an old bell mechanism composed of two 500 ohms coils commutating at about 30 hz during operations.
First, and as I had only that at my disposal, I used a 9V cell. I was able to generate the 24V. I then removed the cell, plugged the 12V regulated source and rotated the screw a bit to obtain the same 24V. The chip then got really hot (but it seems that is normal) and started to produce a little noise, very high pitch. I assumed it was coming from the the coil inside the circuit, nothing serious. After that it seems that no matter how high I would rotate the screw I would still get 12V in the output, but somehow the system was still working fine for a 9V input. After many swaps and different configuration, it seems the system got even weirder as when the 12V was on the measured voltage of the source would drop to 3V only ...
What is seems is that somehow I fried the component by touching it too much (there were a lot of wires, and possibly a few arcs when I was measuring voltages), and that for some reason it kept on working for 9V input, but was in short for 12V, causing it to draw maximum current and leading my regulated source to go under and generate only 3V.
Can someone please confirm that behaviour, or at least what I thought possibly happened ?
Also, has anyone used this component and identified case scenario that are to be avoided, or very sensitive points on that chip? Any help would be much appreciated, I will order one more and start over again in two weeks and I just need to confirm that my burnt chip is only my fault and the the thing is robust enough to survive, but with careful hands