OB6663

OB6663L TM PFC/QR Combo Controller GENERAL DESCRIPTION FEATURES OB6663L integrates a transition mode power factor correction (TM PFC) controller and a QuasiResonant (QR) controller in one chip. The controller provides a cost effective solution for optimizing the power factor. QR provides higher efficiency and lower EMI compared to conventional PWM system. OB6663L provides high level integration and high performance than conventional PFC/PWM system. The built-in dual output control for TM PFC optimizes power conversion efficiency with reduced system cost. Separated analog ground (AGND) and power ground (PGND) provide better noise immunity. OB6663L features many built-in green functions to optimize power conversion efficiency at all power levels. This holds for QR operation at high power levels, as well as PFM operation at lower power levels, and ‘Extended Burst Mode’ operation at very low power or zero power (Standby) levels. At low power levels, OB6663L automatically turns off the PFC stage. In this way, low standby (Vth2, Figure 1), the system operates in QR mode. The frequency varies depending on the line voltage and the load conditions. Therefore, the system may actually work in DCM when 125KHz frequency clamping is reached. System design should be optimized such that the operation frequency is within the range specified at full loading conditions and in universal AC line input range. ■ At light load condition (Vth1