SSC1S311A is the controll IC of a quasi-resonant mode for a switching power supplies. The IC incorporates a startup circuit and a standby function to reduce a power consumption and standby power. In normal operation, the quasi-resonant mode operation achieves high efficiency and low noise. In addition, in medium to low load conditions, the operation mode is automatically changed from the quasi-resonant mode to the bottom-skip mode to improve efficiency. The IC is provided in the SOIC8 package. The power supply that is a low component counts and a high performance-to-cost can be achieved by the rich set of protection features.