OB2269 Datasheet | LITEON

DESCRIPTION OB2268/9 is a highly integrated current mode PWM control IC optimized for high performance, low standby power and cost effective offline flyback converter applications in above 20W power level. PWM switching frequency at normal operation is externally programmable and 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 design with OB2268/9. A large value resistor could thus be used in the startup circuit to minimize the standby power. The internal slope pensation improves system large signal stability and reduces the possible subharmonic oscillation at high PWM duty cycle output. Leading-edge blanking on current sense input removes the signal glitch due to snubber circuit diode reverse recovery. and greatly reduces the external ponent count and system cost in the design. OB2268/9 offers plete protection coverage with automatic self-recovery feature including Cycle-by Cycle current limiting (OCP), over load protection (OLP), over temperature protection (OTP), VDD over voltage protection (OVP) and under voltage lockout (UVLO). The Gate-drive output is clamped to maximum 18V to protect the power MOSFET. Excellent EMI performance is achieved with On Bright proprietary frequency shuffling technique (OB2269 only) together with soft switching control at the totem pole gate drive output. The tone energy at below 20KHZ is minimized in operation. Consequently, audio noise performance is greatly improved. TYPICAL APPLICATION OB2268 OB2269 Current Mode PWM Controller OB2268/9 is offered in SOP-8 and DIP-8 packages. FEATURES - Extended Burst Mode Control For Improved Efficiency and Minimum Standby Power Design - Audio Noise Free Operation - External Programmable PWM Switching Frequency - Internal Synchronized Slope pensation - Low...