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

nPrimary-side sensing and regulation without VDD diode, TL431 and opto-coupler

nHigh precision constant voltage and current regulation at universal AC input

nProgrammable CV and CC regulation

nProgrammable CC line compensation

nBuilt-in cable compensation and primary winding inductance compensation

nNo need for control loop compensation

nSupport dual winding transformer application

nInternal BJT switch

nBuilt-in leading edge blanking (LEB)

nComprehensive protection coverage with auto-recovery

lVDD over voltage protection

lVDD under voltage lockout with hysteresis (UVLO)

lCycle-by-cycle current limiting

lOutput short circuit protection

lOutput under voltage protection(UVP)

lOver temperature protection (OTP)

APPLICATIONS

Low Power AC/DC offline SMPS for

nCell Phone Charger

nDigital Cameras Charger

nSmall Power Adapter

nAuxiliary Power for PC, TV etc.

nLinear Regulator/RCC Replacement

TYPICAL APPLICATION

Figure.2. Dual winding transformer typical application schematic

Figure.3. Three winding transformer typical application schematic

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