GENERAL DESCRIPTION

OB339F is a primary side regulation off-line LED

lighting controller which can achieve accurate LED

current. It significantly simplifies LED lighting

system design by eliminating the secondary side

feedback circuitry. Proprietary Constant Voltage

(CV) and Constant Current (CC) control is

integrated as shown in the figure below.

The LED current (CC control) can be adjusted

externally by the resistor Rs at SOURCE pin.

OB339F offers comprehensive protection

coverage with auto-recovery features including

Cycle-by-Cycle current limiting, VDD OVP, VDD

clamp and UVLO. Excellent EMI performance is

achieved with On-Bright proprietary frequency

shuffling technique.

OB339F is offered in DIP8 package.

FEATURES

 High Precise Constant Current Regulation at

Universal AC input

 Primary-side Sensing and Regulation Without

TL431 and Opto-coupler

 Programmable CC Regulation

 Adjustable Constant Current and Output

Power Setting

 Built-in Secondary Constant Current Control

with Primary Side Feedback

 Built-in Adaptive Current Peak Regulation

 Built-in Primary winding inductance

compensation

 Power on Soft-start

 Built-in Leading Edge Blanking (LEB)

 Cycle-by-Cycle Current Limiting

 VDD Under Voltage Lockout with Hysteresis

(UVLO)

 VDD OVP

 VDD Clamp

APPLICATIONS

Low Power AC/DC offline SMPS for

 LED applications