PMP10804, Primary Side Regulated Flyback Reference Design with 120VAC Input and 24V/4A Rated Output

PMP10804, Reference Design implements the UCC28630 PSR controller in a flyback power supply. The UCC28630 is capable of operating in both Continuous and Discontinuous Conduction Modes which enables high efficiency while reducing inductor size and cost. Safety standards such as EN60950 require that any X-capacitors in EMC filters on the AC side of the bridge rectifier quickly discharge to a safe level when AC is disconnected. Typically, this requirement is achieved by including a resistive discharge element in parallel with the X-capacitor. However, this resistance causes a continuous power dissipation that impacts the standby power performance