OB2279 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 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 OB2279. A large value resistor could thus be used in the startup circuit for reduced power loss. 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 input removes the signal glitch due to snubber circuit diode reverse recovery and greatly reduces the external component count and system cost in the design. OB2279 offers comprehensive protection coverage including Cycle-by-Cycle current limiting(OCP), VDD Under Voltage Lockout(UVLO), VDD Over Voltage Protection(OVP), VDD Clamp, Gate Clamp, Over Load protection(OLP) and Over Temperature protection (OTP). OB2279 offers 3 different version with selective protections set as latch shutdown mode. V version OB2279 has OVP Latch shutdown only. T version OB2279 supports both OVP and OTP latch shutdown. L version OB2279 provides all OVP, OTP and OLP latch shutdown control. Excellent EMI performance is achieved with On- Bright proprietary frequency shuffling technique together with soft switching control at the totem pole gate drive output.