The resonant flyback controller integrates a high-side 650V / 4A 1.2 Ω MOSFET in the package. The system’s power switches, high-side MOSFET and low-side MOSFETs are almost always zero voltage switching (ZVS). Therefore, the switching loss of the power switches can be minimized, and the efficiency can be optimized. This resonant flyback controller can also be used in conjunction with GaN or SiC to meet higher frequency power system design requirements. With the outstanding capabilities, the flyback controller can support power supply applications from 30W to under 200W.