OB2211H is an offline PWM Power switch for low
power AC/DC charger and adaptor applications. It
operates in primary-side sensing and regulation.
Consequently, opto-coupler 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, multi-mode operations are
utilized to achieve high performance and high
efficiency. Device operates in fixed frequency mode
at large load conditions, frequency reduction mode at
light/medium load and ‘Extended burst mode’ at
No/light load conditions.
OB2211H offers power on soft start control and
protection coverage with auto-recovery features
including Cycle-by-Cycle current limiting, VDD
clamp and UVLO. Excellent EMI performance is
achieved with On-Bright proprietary frequency
shuffling technique together with soft switching
control at the totem pole gate drive output.
OB2211H achieves better CC control accuracy and
higher system efficiency through PWM control than
its sibling part OB2211.