The ON Semiconductor NCL37733 is a compact driver for power−factor corrected flyback and non−isolated buck−boost and SEPIC converter. The controller operates in a quasi−resonant mode to provide optimal efficiency, and embeds a proprietary control method which allows the LED current to be tightly regulated from the primary side, thus eliminating the need for a secondary−side feedback circuitry and for an optocoupler.

Near−unity power factor (>0.95 typically)
Optimized for line wide−range application
Line feed forward for enhanced regulation accuracy
Low start−up current (10 A typ.)
Wide VCC range