OB2353

OB2353 Low Power Off Line SMPS Switcher Freq Shuffling GENERAL DESCRIPTION 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 PWM frequency operates in the fixed and 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-byCycle 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 driv...