High Performance， Combined Driver， Controller， Switch The LYTSwitch-4 family enables off-line LED drivers with high power factor which easily meet international requirements for THD and harmonics. Output current is tightly regulated with better than ±5% CC tolerance1 。 Efficiency of up to 92% is easily achieved in typical applications. Supports a Wide Selection of TRIAC Dimmers The LYTSwitch-4 family provides excellent turn-on characteristics for leading-edge and trailing-edge TRIAC dimming applications. This results in drivers with a wide dimming range and fast start-up， even when turning on from a low conduction angle – large dimming ratio and low “pop-on” current. Low Solution Cost and Long Lifetime LYTSwitch-4 ICs are highly integrated and employ a primary-side control technique that eliminates the optoisolator and reduces component count. This allows the use of low-cost single-sided printed circuit boards. Combining PFC and CC functions into a single-stage also helps reduce cost and increase efficiency. The 132 kHz switching frequency permits the use of small， low-cost magnetics. LED drivers using the LYTSwitch-4 family do not use primaryside aluminum electrolytic bulk capacitors. This means greatly extended driver lifetime， especially in bulb and other high temperature applications.