GENERAL DESCRIPTION
OB3398Ex is a primary side regulation off-line LED lighting power switch 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 CS pin.
OB3398Ex offers comprehensive protection coverage with auto-recovery features including Cycle-by-Cycle current limiting, VDD clamp and UVLO.
OB3398Ex is offered in DIP8/SOP7 package.
Fig.1. Typical CC/CV Curve
FEATURES
High Precise Constant Current Regulation at Universal AC input
Primary-side Sensing and Regulation Without TL431 and Opto-coupler
HV MOSFET integrated
Floating PSR control scheme with two transformer windings
Adjustable Constant Current and Output Power Setting
Built-in Primary winding inductance compensation
Built-in Leading Edge Blanking (LEB)
Cycle-by-Cycle Current Limiting
VDD Under Voltage Lockout with Hysteresis (UVLO)
Latched over temperature protection (OTP)
VDD Clamp
APPLICATIONS
Low Power AC/DC offline SMPS for
LED applications