The NCL30186 is an AC-DC power factor corrected flyback controller targeting isolated and non−isolated “Smart−dimmable” constant current LED drivers. The controller operates in a quasi−resonant mode to provide optimal efficiency. The current control algorithm supports flyback, buck−boost, and SEPIC topologies. Thanks to a novel control method, the device is able to tightly regulate a constant LED currentfrom the primary side. This removes the need for secondary side feedback circuitry, biasing and an optocoupler.The device is highly integrated with a minimum number of external components. A robust suite of safety protection is built in to simplify the design. This device is specifically intended for very compact space efficient designs and supports analog and PWM dimming with a dedicated dimming input intended to control the average LED current. To ensure reliable operation at elevated temperatures, a user configurable current foldback circuit is also provided. The NCL30086 is housed inthe SOIC10 which has the same body size as a standard SOIC8.