WS3252
WS3252 High Precision CC/CV Primary-Side PWM Controller
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
General Description
WS3252 is a high-integrated offline PWM controller,
optemized for high poformance low power AC/DC charger
and adapter adapter application.
WS3252 operates in primary-side sensing and regulation.
Consequently, opto-coupler 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.
V o
5 %
Applications
Low power AC/DC offline SMPS for
■ Cell Phone Charger
■ Digital Cameras Charger
■ Small Power Adapter
■ Auxiliary Power for PC, TV etc.
■ Linear Regulator/RCC Replacement
I o
WS3252 offers power on soft start control and protection
coverage
with
auto-recovery
features
including
Cycle-by-Cycle current limiting, VCC OVP,VCC clamp and
UVLO. The gate-driven output is clamped to maximum 12V
to protect the internal MOSFET. Excellent EMI performance
is achieved by using the soft-switching and frequency jittering
at the totem-pole-gate-drive output. The WS3252 is the ideal
substitute of the linear power supply or the RCC-mod e
power, for a better performance of the whole switch power
system and a lower cost.
WS3252 is available in SOT23-6 package.
Icc
Typical Application Circuit
Rev.A Sep.2011
WINSEMI [ SHENZHEN WINSEMI MICROELECTRONICS CO., LTD ]
