The FL7740 provides accurate CV regulation in the steady state with differentiated dynamic function to minimize overshoot and undershoot of output voltage in line and load transient condition. Standby power is less than 0.3 W for smart lighting application and power factor is higher than 0.9 even at half load condition when enabling PF optimizer for wide output power scalability. Startup time is less than 0.2 sec with built-in high voltage startup circuit and output voltage reaches to the target CV level by loop gain transition technique during startup. Various protections such as over load, output diode short, sensing resistor short, output short and over voltage protection guarantee high system reliability.