OB5225 is a highly integrated current mode PWM power combo IC. It is designed with HV startup, optimized for high efficiency, ultra low standby power consumption and cost effective offline flyback converter applications.

PWM switching frequency at normal operation is internally fixed and is trimmed to a tight range. At no load or light load condition, the IC operates in extended ‘burst mode’ to minimize switching loss. Very low standby power consumption and very high conversion efficiency is thus achieved.

High voltage startup is implemented in OB5225, which features with short startup time and low standby current.

OB5225 offers complete protection coverage with auto-recovery including Cycle-by-Cycle current limiting (OCP), over load protection (OLP), brownout protection and VDD under voltage lockout (UVLO) ,over temperature protection (OTP).  It also provides the protection with latched shut down including VDD over voltage protection. Excellent EMI performance is achieved with On-Bright proprietary frequency shuffling technique.

The tone energy at below 22KHZ is minimized to avoid audio noise during operation.

OB5225 is offered in DIP8 package.


  • Built-in High Voltage Startup

  • Integrated with HV MOSFET

  • Power on Soft Start Reducing MOSFET Vds Stress

  • Frequency shuffling for EMI

  • Extended Burst Mode Control For Improved Efficiency and Minimum Standby Power

  • Audio Noise Free Operation

  • Fixed 65KHZ Switching Frequency

  • Comprehensive Protection Coverage

    • VDD Under Voltage Lockout with Hysteresis (UVLO)       

    • Cycle-by-cycle over current protection (OCP)

    • Overload Protection (OLP) with auto-recovery

    • Brownout Protection with auto-recovery

    • Over Temperature Protection (OTP) with auto-recovery

    • VDD Over voltage Protection(OVP) with latch shut down

  • Intelligent AC off Detect with X-cap discharge  function (On-Bright patent)



    Offline AC/DC flyback converter for

  • AC/DC Adapter

  • PDA Power Supplies

  • Digital Cameras and Camcorder Adapter


  • Set-Top Box Power

  • Auxiliary Power Supply for PC and Server

  • Open-frame SMPS