The SS1203 is a current mode PWM switching power supply controller that specifically designed for AC/DCconverter with high performance versus cost ratio. It provides continuous output power up to 12W in the broad voltage range of 85V – 265V.Its optimized and highly reasonable circuit design has made it possible to minimize the total cost of the
product. This power supply controller could be used in typical flyback circuit topology to constitute simple AC/DC converter. The internal initiating circuit of SS1203 has been designed with a unique means of current sink to complete the startup using the amplifying function of the power switching tube. This will significantly reduce the power consumption of the start-up resistor; and when the output power becomes smaller, SS1203 will automatically lower its operating frequency to enable very low standby power consumption.