This series of PWM-type DC/DC converters for AC/DC supplies the optimum system for all products in which an outlet is present. It is compatible with both insulated and non-insulated, and various types of low-power consumption converters can be easily designed. The built-in 730V startup circuit contributes to low power dissipation. A highly flexible power supply design is achieved by externally installing a current detection resistor for switching. Because of the use of current mode control, the current is limited every cycle, providing excellent performance in bandwidth and excessive response. The switching frequency is fixed at 100kHz. When turned light load, the frequency is reduced to achieve high efficiency. Built-in frequency hopping function contributes to low EMI. Built-in 730V switching MOSFET enables easy designing.