The NCP1343AMDCDBD1R2G from ON Semiconductor is a high frequency quasi-resonant flyback controller designed to offer users flexibility, energy efficiency, and high power density. It is an integrated circuit which contains an external MOSFET gate driver which provides an efficient, cost effective, and extremely compact solution for flyback and quasi-resonant topologies. The flyback switching controllers are optimized for light load efficiency by using a sloped-valley off-time control that provides highly accurate constant off-time control throughout light and heavy load conditions. The device also features a low drop-out ramp voltage, an adjustable on-time control, and an active valley-fill that improves light load efficiency with a decrease in EMI. It also has an integrated soft start and a leader-follower soft start phase-shift PWM control for increased EMI performance. The NCP1343AMDCDBD1R2G is ideal for high power density applications, such as SMPS/power adaptors, remote switches, ballasts, and set-top boxes.