OB6683 integrates a transition mode power factor correction (TM PFC) controller and a Quasi-Resonant (QR) controller in one chip. The PFC controller provides a cost effective solution for optimizing the power factor. The QR controller provides higher efficiency and lower EMI compared to conventional PWM system.

OB6683 provides high level integration and high performance than conventional PFC/PWM system. The built-in TM PFC controller optimizes power conversion efficiency with reduced system cost. The intelligent PFC switching ON and OFF, zero current detection and frequency limitation mechanism enable a better efficiency under any load conditions.

OB6683 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, OB6683G can turn off the PFC stage. In this way, low standby together with low system cost can be achieved.

The device is also integrated many functions of protection, such as X-CAP discharge, Brown-in/out protection, VCC Under Voltage Lockout (UVLO), Cycle-by-Cycle Current Limiting for PFC and QR Stage (OCP), Output Over Voltage Protection for PFC and QR Stage (OVP), Open Loop Protection for PFC and QR Stage (OLP), Programmable Over Temperature Protection (OTP), Built-in Soft Start in QR Stage, VCC Over Voltage Protection, Gate Clamp , Pin Floating Protection, and External Latch Triggering,  etc.  Therefore it can protect the system from damage due to occasional failure.

OB6683 is offered in SOP-16 packages.


   Integrated PFC Controller and QR  Controller

   Transition Mode PFC Controller

   Multi-Mode Operation for QR Stage

   Line Voltage Compensation for QR Stage

   Enhanced Dynamic Response for PFC Stage

   PFC Light Load Turn Off Control

   Audio Noise Free Operation

   Valley Switching Operation with Valley lockout

   External Latch Triggering for Both Converters

   Minimum OFF time for Ringing Suppression

   Maximum ON Time Limit for QR Stage

   Built-in 4ms Soft Start for QR Stage

   Internal Leading Edge Blanking for QR Stage

   Internal Leading Edge Blanking for PFC Stage

   Built-in X-CAP Discharge



   Output Over Voltage Protection for PFC stage

   Output Over Voltage Protection for QR stage

   Output Diode Short Protection for QR stage

   VCC Over Voltage Protection

   Under Voltage Lockout with Hysteresis

   Over Load Protection for QR stage

   Cycle-by-Cycle Current Limiting for PFC stage

   Cycle-by-Cycle Current Limiting for QR stage

   Brownout Protection (BOP)

   PFC Inductor Short Circuit Protection

   Programmable Over Temperature Protection

   Internal Over Temperature Protection



Offline AC/DC flyback converter for

   General LED Lighting

   LCD Monitor/TV/PC


   ACDC High Power Adapter

   Open Frame SMPS