OB2269MM/TR-HG

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 can be programmed via an external component and precisely adjusted within a narrow range. Under no-load or light-load conditions, the IC operates in an extended "Burst Mode" to minimize switching losses, thereby achieving lower standby power consumption and higher conversion efficiency. The low VDD startup current and low operating current enable the OB2269 to achieve reliable power-on startup and low standby design. As a result, high-value resistors can be used in the startup circuit to minimize standby power dissipation. Internal slope compensation improves large-signal stability and reduces sub-harmonic oscillation that may occur at high PWM duty cycle outputs. The leading-edge blanking function on the current sense input eliminates signal glitches caused by snubber circuit diode reverse recovery, which greatly helps reduce the number of external components and system cost in the application. The OB2269 provides comprehensive protection features with automatic self-recovery, including cycle-by-cycle current limiting (OCP), overload protection (OLP), VDD under-voltage lockout (UVLO), over-temperature protection (OTP), and over-voltage 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 across the universal AC input range. Excellent EMI performance is achieved through internal frequency jitter technology and soft-switching control of the totem-pole gate drive output. The design minimizes audio-frequency energy below 22KHz and eliminates audio noise. The OB2269 is available in SOP-8, MSOP-8, and DIP-8 packages.

Applications

• Offline AC/DC flyback converter for:
• AC/DC adapters
• Set-top box power supplies
• Auxiliary power supplies
• Open-frame switching power supplies
• Battery chargers

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 synchronized slope compensation
• Low VIN/VDD startup current (6.5μA) and low operating current (2.0mA)
• Comprehensive protection with auto-recovery
• VDD UVLO with hysteresis
• Cycle-by-cycle overcurrent protection
• Overload protection (OLP)
• Over-temperature protection (OTP)
• VDD overvoltage protection (OVP)
• Available in DIP-8, SOP-8, and MSOP-8 packages