WS2273
2273 Current Mode PWM Controller
Features
■ Burst Mode Control
■ 5uA ultra-low startup current
■ 1.8mA Low operating current
■ Built-in Leading-edge blanking
■ Built-in synchronous slope compensation circuit
■ Built-in Soft-Start
■ 65kHz fixed swith frequency
■ Cycle by cycle over current protection (OCP)
■ VCC over voltage clamp & under voltage lockout( UVLO)
■ Over load protection (OLP)
■ OTP and OVP shut down latch
■ Maximum Gate output voltage clamped at 12V
■ Frequency jittering
■ Adjustable OVP through external Zener
General Description
2273 is a high performance current mode PWM controller,
optimized for low power power switch equipment.
For lower the standby power and higher RoHS compliant,
the IC offers a Burst Mode control feature and ultra-low
start-up current and operating current, that is, at the
condition of no load or light load, 2273 can reduce the
switch frequency linearly which minimize the switching
power loss; the ultra-low startup current and operating
current make a reliable power for startup design, and also
large resistor can be used in the startup circuit to improve
switching efficiency. The internal synchronous slope
compensation circuit reduces the possible subharmonic
oscillation at high PWM duty cycle output. Leading-edge
blanking on current sense(CS) input removes the signal
glitch due to snubber diode circuit reverse recovery and
thus greatly reduces the external component count and
system cost in the design. 2273 offers comprehensive
protection coverage with automatic self-recovery feature,
including cycle by cycle over current protection (OCP),
over load protection (OLP),VCC Clamp, under voltage
lockout (UVLO), OTP and OVP shut down latch. 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 tone energy at below
20KHZ is minimized in the design and audio noise is
eliminat- ed during operation. The 2273 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.
2273 is available in SOT23-6 package.
Applications
Universal switch power supply equipment and offline
AC/DC flyback power converter
■ Power Adapter
■ Set-Top Box Power Supplies
■ Open-frame SMPS
■ Battery Charger
Typical Application Circuit
Rev.A Oct.2011
WINSEMI [ SHENZHEN WINSEMI MICROELECTRONICS CO., LTD ]
