OB2269N

The OB2269 integrates a highly integrated current-mode PWM control IC, optimized for high-performance, low standby power, and cost-effective offline flyback converter applications. During normal operation, the PWM switching frequency is externally programmable and can be fine-tuned within a narrow range. Under no-load or light-load conditions, the IC operates in an extended "Burst Mode" to minimize switching losses, achieving lower standby power consumption and higher conversion efficiency. The low startup current and low operating current of VDD contribute to reliable power-on startup and low standby design. Internal slope compensation improves large-signal stability and reduces subharmonic oscillation that may occur at high PWM duty cycle outputs. Leading-edge blanking on the current sense input eliminates signal glitches caused by snubber diode reverse recovery, helping to reduce the number of external components and system cost in applications. The OB2269 provides comprehensive protection features with automatic self-recovery, including cycle-by-cycle current limiting (OCP), overload protection (OLP), VDD undervoltage lockout (UVLO), over-temperature protection (OTP), and overvoltage protection (OVP). The gate drive output is clamped at 18V to protect the power MOSFET. In the OB2269, the OCP threshold slope is internally optimized to achieve constant output power limiting over the universal AC input range. Excellent EMI performance is achieved through internal frequency dithering and soft-switching control of the totem-pole gate drive output. Tonal energy below 22KHz is minimized in the design, eliminating audio noise. The OB2269 is available in SOP-8, MSOP-8, and DIP-8 packages.

Applications

• Offline AC/DC flyback converter
• AC/DC adapter
• Set-top box power supply
• Auxiliary power supply
• Open-frame switching power supply

Key features

• Extended burst mode control for improved efficiency and minimum standby power design
• Soft-start at power-up to reduce MOSFET stress
• Audio-noise-free operation
• Externally programmable PWM switching frequency
• Low VDD startup and operating current
• Frequency dithering for minimized EMI
• Leading-edge blanking for current sensing
• Internal synchronous slope compensation
• Low VIN/VDD startup current (6.5uA) and low operating current (2.0mA)
• Comprehensive protection with auto-recovery - VDD undervoltage lockout with hysteresis (UVLO)
• Cycle-by-cycle overcurrent protection
• Overload protection (OLP)
• Over-temperature protection (OTP)
• VDD overvoltage protection (OVP)
• Available in DIP-8, SOP-8, MSOP-8 packages