LED Dimming Control

OK, it is possible it is a fixed current regulator, in which case the current sense resistor is the only component that controls the current. But, on a number of these chips, there is another resistor in a signal-level reference circuit that also sets the current. But, if it is a 4-pin or so chip, then you are probably right.

Jon

Interesting. I was trying to figure out what is "special" about the Y capacitor and it seems they are rated for safety since a short can be dangerous. On illustration shows the use of metallized film caps melting the area around a short eliminating the short. But where does the metal go? It's sealed inside the cap. Does it pool up and form a bead around the hole? It certainly doesn't just disappear.

This is a *very* cheap unit from eBay. It's good to know they would include a part like this for EMI. I would have expect it to be a bare bones design with no regard to standards.

even the cheapest death trap china special USB chargers usually have them though you ever know if they are floor weepings with fake markings ..

-Lasse

I was just nosing around the bpsemi site and they have what would appear to be the same identical chip with two unused pins wired, one for a dimmer function! So I should be able to replace the chip on the board and add a dimming control very easily. Awesome!