Jiyuan provides MOSFET integrated flyback converters to simplify circuit design for 30W and below applications, and also provides flyback controller solutions for higher power applications. Our product family is divided into 2 sub-families: primary side regulation flyback and secondary side regulation flyback. Primary side regulation flyback can save the opto-coupler and secondary feedback unit, which largely reduces the components number and solution size. Secondary side regulation flyback provides higher regulation accuracy and faster transient response, which is important for chargers and other applications.

Primary regulation flybacks use the transformer winding to sense output voltage, so it does not need optocoupler and a secondary voltage sense circuit, largely reducing the component number and shrinking the solution size. But the drawback is regulation will not be as good as secondary regulation due to the transformer coupling, and secondary diode dropout voltage leading to the difference of output voltage and sense voltage. Primary regulation dynamic performance is also worse than secondary regulation. Usually primary regulation is used in low power(<40W) application without high accuracy requirement; for higher power applications, usually secondary regulation is more popular.