onsemi Non-Isolated Evaluation Board Flyback Converter for MMSZ5229BT1G, NCP1075STBT3G, NST45011MW6T1G for 8W Dual

This evaluation board features an 8 watt, off-line, dual output, flyback power supply intended for powering white goods or industrial equipment circuitry which does not require output isolation from the AC mains. The flyback converter is designed around ON Semiconductor's 100 kHz NCP1075 monolithic switching controller. A simple voltage sensing and feedback scheme utilizing a current mirror transistor pair (Q1), and zener diode (Z1) is utilized for low cost yet effective output regulation for most typical applications.

Schottky diodes (D6, D7) on both outputs for high efficiency
Dual sensing options depending on desired regulation accuracy
Input EMI filter for conducted emission compliance
Input fuse and inrush limiting resistor (R1)
Good load and cross regulation on 8.5Vout due to secondary winding technique on transformer