Check out this link for On Semiconductor’s datasheet for a line of “Zero-Cross Optocoupled Triac Drivers.” The ability to zero-cross when turning on AC line voltage to some loads may be advantageous.
Non-insulated power supplies are often required when a power semiconductor, which has to be controlled using this supply, has its drive reference connected to the mains (line or neutral terminal).
The LM3445 from National Semiconductor enables a full 100:1 range of offline, uniform, flicker-free dimming for high-brightness LEDs with a conventional TRIAC forward or reverse phase-control wall ...