The Quasi-Resonant, ICE5QSAG is the 5th generation of quasiresonant controller optimized for off-line switch power supply in cascode configuration. The improved digital frequency reduction with proprietary novel Quasi-Resonant operation offers lower EMI and higher efficiency for wide AC range by reducing the switching frequency difference between low and high line. The enhanced active burst mode enables flexibility in standby power range selection. The product has a wide operating range (10~25.5 V) of IC power supply and lower power consumption. The numerous protection functions including the robust line protection (both input OVP and brownout) to support the protections of the power supply system in failure situations. All of these make the ICE5QSAG an outstanding controller for Quasi-Resonant flyback converter in the market.