WS3255

WS3255 Product Description High Precision Primary-Side Off-line PWM Power Switch Features � 5uA ultra-low startup current � 2mA Low operating current � ±5% Constant Voltage Regulation at Universal AC input � Primary-side Sensing and Regulation Without TL431 and Opto-coupler � Programmable CV and CC Regulation � Built-in Primary winding inductance compensation � Programmable cable drop compensation � Built-in soft start � Built-in Leading-edge blanking � Cycle by cycle over current protection (OCP) � VCC over voltage clamp & under voltage lockout( UVLO) � Maximum Gate output voltage clamped at 12V � Frequency jittering � Ultra low standby power (<100mW) WS3255 operates in primary-side sensing and regulation. Consequently, optocoupler and TL431 could be eliminated, thus reduce the cost. It can achieve ±5% constant voltage precision in full input voltage range. CC/CV Control as shown in fig.1.In CC Control, the current and output power setting can be adjusted externally by the sense resistor Rs at CS pin. In CV control, multi-mode operations are utilized to achieve high performance and high efficiency. In addition, good load regulation is achieved by the built-in cable drop compensation. Device operates in PFM in CC mode as well at large load condition and it operates in PWM with frequency reduction at light/medium load. Vo 5% Applications Low power AC/DC offline SMPS for � Cell Phone Charger � Digital Cameras Charger � Small Power Adapter � Auxiliary Power for PC, TV etc. �...