VIPER25 is an off-line converter with an 800 V rugged power section, a PWM control, double levels of overcurrent protection, overvoltage and overload protections, hysteretic thermal protection, soft-start and safe auto-restart after any fault condition removal. Burst mode operation and device very low consumption helps to meet the standby energy saving regulations. The quasiresonant feature reduces EMI filter cost. Brownout and brown-in function protects the switch mode power supply when the rectified input voltage level is below the normal minimum level specified for the system. The high voltage start-up circuit is embedded in the device.