I'm working on a couple of projects where we've had a very hard time obtaining LED lighting and dimming that will smoothly dim to zero. We've gotten some that dim to about 20, then slam off; slam back on again when raising the dimming.

Only one approach has worked: A lutron dimming module intended for a magnetic load; near the LEDs a 230V to 12V transformer (AC is 230V here), a full wave rectifier, and a capacitor. And even then, the transformer and capacitor have to be chosen carefully because have too much current available messes up the dimming, and there's a sweet spot of capacitance which filters well enough but doesn't store so much energy that it slows the dimming.

If you've got 12V or other low voltage lighting, how are you dimming it?

I've come to believe that smooth dimming is beyond the state of the art, at least for high voltage LED bulbs, like 120V or 230V. They do not seem to be capable of being dimmed as we'd like because the internal drivers require a certain minimum voltage to operate.