OB25143
GENERAL DESCRIPTION
OB2514x is a high performance offline PSR power switch for low power AC/DC charger and adapter applications. It operates in primary-side sensing and regulation. Consequently, opto-coupler，VDD diode and TL431 could be eliminated. Proprietary Constant Voltage (CV) and Constant Current (CC) control is integrated as shown in the figure below.
In CC control, the current and output power setting can be adjusted externally by the sense resistor Rs at CS pin. In CV control, device operates in PFM. The chip consumes very low operation current, it can achieve less than 75mW standby power.
OB2514x offers comprehensive protection coverage with auto-recovery features including Cycle-by-Cycle current limiting, VDD over voltage protection, short circuit protection, built-in leading edge blanking, VDD under voltage lockout (UVLO), OTP etc.
OB2514x is offered in CDFN8-7package.
Figure.1. Typical CC/CV Curve
FEATURES
n Primary-side sensing and regulation without VDD diode, TL431 and opto-coupler
n High precision constant voltage and current regulation at universal AC input
n Programmable CV and CC regulation
n Programmable CC line compensation
n Built-in cable compensation and primary winding inductance compensation
n No need for control loop compensation
n Support dual winding transformer application
n Internal BJT switch
n Built-in leading edge blanking (LEB)
n Comprehensive protection coverage with auto-recovery
l VDD over voltage protection
l VDD under voltage lockout with hysteresis (UVLO)
l Cycle-by-cycle current limiting
l Output short circuit protection
l Output under voltage protection(UVP)
l Over temperature protection (OTP)
APPLICATIONS
Low Power AC/DC offline SMPS for
n Cell Phone Charger
n Digital Cameras Charger
n Small Power Adapter
n Auxiliary Power for PC, TV etc.
n Linear Regulator/RCC Replacement
TYPICAL APPLICATION
Figure.2. Dual winding transformer typical application schematic
Figure.3. Three winding transformer typical application schematic