Magnetics for Quasi-Resonant Primary Side Current-Mode Controllers

Custom magnetics from Wurth Electronics Midcom are intended for use with ON Semiconductor's NCL30080 series of quasi-resonant primary-side current mode controllers.

The magnetics developed include custom-wound transformers for isolated applications and a custom-wound inductor for non-isolated applications, including flyback transformers in the 4 and 10W power range for isolated LED lighting applications and a less than 1mH inductor with an auxiliary winding for non-isolated buck-boost applications. Standard drum core inductors are used for the input filtering and EMI reduction.

The high-performing, low-leakage inductance transformers are designed to meet reinforced insulation requirements defined by IEC61347 and can withstand a dielectric voltage of 3000VRMS for one minute for a primary circuit at a working voltage of 400VDC. The operating temperature of these custom magnetics is -40°C to +125°C.

The NCL30080 series - including NCL30080, NCL30081, NCL30082, and NCL30083 - incorporate a novel control method to precisely regulate a constant LED current from the primary side, removing the need for secondary side feedback circuitry The family includes versions with thermal foldback, 5-step log-dimming, analog/digital dimming, and soft-start.