OB2353 combines a dedicated current mode PWM
controller with integrated high voltage power
MOSFET .It is optimized for high performance
low standby power and cost effective offline flyback
converter applications in sub 10W range.
OB2353 operates in the fixed PWM frequency ,the
frequency is set internal and it is accurately trimmed .
At no load or light load the frequency is internal
adjusted, 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 design with
OB2353. A large value resistor could thus be used in
the startup circuit to minimize the standby power.
The internal slope compensation improves system
large signal stability and 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 circuit diode
reverse recovery and thus greatly reduces the external
component count and system cost in the design.
OB2353 offers complete protection coverage with
automatic self-recovery feature including Cycle-by-
Cycle current limiting (OCP), over load protection
(OLP), VDD over voltage clamp and under voltage
lockout (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.