The NCL30388 is a power factor corrected flyback controller targeting isolated constant current LED drivers. The controller operates in a quasi-resonant mode to provide high efficiency. Thanks to a novel control method, the device is able to tightly regulate a constant LED current from the primary side. This removes the need for secondary side feedback circuitry, its biasing and for 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.