The TOPSwitch-HX is a highly integrated monolithic off-line switcher IC designed for off-line power supplies. TOPSwitch-HX integrated circuits enable design of power supplies up to 195 W, while providing high effi ciency under all load conditions. TOPSwitch-HX also provides very good performance at low load and during standby (no load) operation. The TOPSwitch-HX family allows the designer to meet the effi ciency requirements for the new energy-effi ciency standards. Innovative and proprietary features enable design of compact and cost effective switching power supplies while reducing overall design cycle time and system cost. The TOPSwitch-HX family also enables the design of power supplies with robust functionality and provides enhanced safety features such as output overvoltage protection, overload power limiting and hysteretic thermal protection.