The STEVAL-ISA121V1 demonstration board implements a 15 W single-output wide range mains power supply to be used as an auxiliary adapter in applications such as LCD, plasma or LED TVs, desktop computers, etc., when the main power supply is OFF or in standby mode and the auxiliary power supply must provide energy only to some specific parts of the equipment such as USB ports, remote receiver, etc. The board uses the new VIPER37LE, an offline high voltage converter from the VIPerPlus family, specifically designed for fixed frequency flyback converters, which combines a high-performance low voltage PWM controller chip and a max. 4.5 Ω RDS(on), 800 V BV(DSS), avalanche-rugged power MOSFET in the same package. The application is optimized for less than 30 mW standby consumption and meets EPA 2.0 limits, thereby helping to meet the most stringent energy-saving requirements. The board implements several protection features that considerably increase end-product safety and reliability: overload protection, overvoltage protection, brownout protection, hysteretic thermal protection, shorted secondary rectifier detection, and transformer saturation protection, all of which are in auto-restart mode.