High Performance Current Mode PWM Controller
OB2273A is a highly integrated current mode
PWM control IC optimized for high performance,
low standby power and cost effective offline
flyback converter applications.
PWM switching frequency at normal operation is
internally fixed and is trimmed to tight range. At no
load or light load condition, the IC operates in
extended ‘burst mode’ to minimize switching loss.
Lower standby power and higher conversion
efficiency is thus achieved.
VDD low startup current and low operating current
contribute to a reliable power on startup and low
standby design with OB2273A.
OB2273A offers complete protection coverage
with auto-recovery including Cycle-by-Cycle
current limiting (OCP), over load protection (OLP),
VDD under voltage lockout (UVLO), over
temperature protection (OTP), and over voltage
(fixed or adjustable) protection (OVP). Excellent
EMI performance is achieved with On-Bright
proprietary frequency shuffling technique.
The tone energy at below 20KHZ is minimized in
the design and audio noise is eliminated during
OB2273A is offered in SOT23-6 package.
■ Level 5 compliance with <100mW standby
power at universal AC input.
■ Power on Soft Start Reducing MOSFET Vds
■ Frequency shuffling for EMI
■ Extended Burst Mode Control For Improved
Efficiency and Minimum Standby Power
■ Audio Noise Free Operation
■ Fixed 65KHZ Switching Frequency
■ Comprehensive Protection Coverage
o VDD Under Voltage Lockout with
o Cycle-by-cycle over current threshold
setting for constant output power limiting
over universal input voltage range
o Overload Protection (OLP) with auto-
o Over Temperature Protection (OTP) with
o VDD Over voltage Protection(OVP) with
o Adjustable OVP through external Zener
Offline AC/DC flyback converter for
■ Battery Charger
■ Power Adaptor
■ Set-Top Box Power Supplies
■ Open-frame SMPS