one is controller chip and other is HV MOSFET chips. The IC can achieve lower EMI and higher efficiency with improved digital frequency reduction through the proprietary novel Quasi-Resonant operation. The enhanced Active Burst Mode enables flexibility in standby power range selection. The product has a wide operation range of IC power supply and lower power consumption. The numerous protection functions including the robust line protection to support the protections of the power supply system in failure situations. All of these make the CoolSET series an outstanding integrated power device in Quasi-resonant fly back converter in the market.