GENERAL DESCRIPTION

OB6683 integrates a transition mode power factor

correction (TM PFC) controller and a QuasiResonant (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, OB6683 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, Brownin/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.

FEATURES

■ 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

■ 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

PROTECTIONS

■ 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)

■ Programmable Over Temperature Protection

■ Internal Over Temperature Protection

APPLICATIONS

Offline AC/DC flyback converter for

■ General LED Lighting

■ LCD Monitor/TV/PC

■ Notebook

■ ACDC High Power Adapter

■ Open Frame SMPS