OB5283

GENERAL DESCRIPTION

OB5283 is a highly integrated current mode PWM control IC with high voltage startup, optimized for high performance, low standby power consumption and cost effective offline flyback converter applications. The controller‘s HV pin  is used for high voltage startup, AC off detection, and X-cap Voltage discharge , this structure allows the brownout detection as well.

At full loading, the IC operates in fixed frequency (65KHz) mode. When the loading goes low, it operates in Green mode with valley switching for high power conversion efficiency. When the load is very small, the IC operates in ‘Extended Burst Mode’ to minimize the standby power loss. As a result, high conversion efficiency can be achieved in the whole loading range.

High voltage startup is implemented in OB5283, which features with short startup time and low standby power loss.

OB5283 offers complete protection coverage  including cycle-by-cycle current limiting (OCP), over load protection (OLP), over temperature protection (OTP), output short(SCP), output and VDD over voltage protection.  Excellent EMI performance is achieved with On-Bright proprietary frequency shuffling technique.

The tone energy at below 25KHz is minimized to avoid audio noise during operation.

OB5283 is offered in SOP8 package.

 

FEATURES

• High voltage startup

• Power on soft start reducing MOSFET Vds stress

• Frequency shuffling for EMI

• Multi-Mode Operation

  125KHz max frequency mode @ Peak Load

  65KHz fix  frequency mode @ Full Load

  Valley switching operation @ Green mode

    Burst Mode @ Light Load & No Load

• Audio noise free operation

• Peak power delivery for peak load

• Tighten and programmable output over current protection

• Comprehensive protection coverage

  • VDD under voltage lockout with hysteresis (UVLO)       

  • Cycle-by-cycle over current protection (OCP) with auto-recovery

  • Overload protection (OLP) with auto-recovery

  • Over temperature protection (OTP) with latch shut down

  • VDD over voltage protection with latch shut down

  • Output over voltage protection with latch shut down

  • Output short protection (SCP) with auto-recovery

  • Brownout protection with auto-recovery

  • Output diode short protection with latch shut down

• Intelligent AC off detection with X-CAP discharge function

    

  APPLICATIONS

  Offline AC/DC flyback converter for

• Power adaptor

• Open-frame SMPS

• PK Load Application

   

  TYPICAL APPLICATION