High Voltage Input (184Vac…707Vac) to 12V@1A: 3.3V@100mA Non-isolated Flyback Reference Design
The UCC28720 is a quasi resonant controller and is specialized to drive high voltage BJTs. When the drain voltage is higher than 1KV: BJTs are the best choice for low to mid power flyback converters. In this case two voltages are supplied: 12V@1A and 3.3V@100mA.
Over 84% efficiency at full loadOver 70% efficiency at 10% loadProvides 12V and 3.3V outputsWorks continuously up to 440Vac input and survives 1KVpeak surge