I have a few lcd open panel screens I've modified with higher powered led strips instead of ccfl. In doing this I needed to add led drivers for voltage and current regulation. When utilizing the same power source there is so much noise and static and interference that the screen shuts down. When not changing anything except running the power to the drivers via a seperste power source (even non-grounded AC/dc) I get no interference at all. I built an LC filter which helped a bit but these are still unusable. I need to use them off the same power source because they are portable. I can't seem to figure out how to reduce the interference. Any ideas?
Ok - figured this out (but I don't understand how the solution works). It is a grounding issue that causes the interference (static on the LCD). If I run two separate power and ground cables to the same battery source, static appears (tried everything, LC filter, twisted wires, inductors, caps. No difference). To solve the issue I needed to run the ground (and vcc) cable from the power source and attach it to the LCD controller. I then run a long ground cable from each component to the actual back of the LCD (which is metal as it is open frame). I stripped and exposed a couple inches of wire from each cable and put them on opposite corners, the further the better. Attached them by wedging them on the corners - couldn't solder as it is aluminum back panel. This was the only way to remove the static on the screen, having ground go through the panel. Issue solved - why this works I don't know.