Transformer Selection Calculation for the design of Flyback Switching Power Supply

Pulse-width modulating (PWM) is one of the most popular methods to design the switching power supply. The framework to design a novel flyback switching power supply with a PWM integrated circuit is described in this paper. In order to meet the design demand, the significant step of transformer selection calculation is discussed in details. AP method is used in the transformer calculation. Then some other parameters of the transformer, such as the transformer ratio, Primary current of transformer, the primary inductance of transformer, the transformer turn and air gap and the wire diameter of the winding, are computed step by step. With the selected transformer, the proposed switching power supply has simpler circuit and higher accuracy. Different input voltage ranges and output voltages required by different electric appliances can be well satisfied.